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| author | Eric S. Raymond | 1993-03-22 16:57:31 +0000 |
|---|---|---|
| committer | Eric S. Raymond | 1993-03-22 16:57:31 +0000 |
| commit | eb708e87ade8035dfa454097f63a6f1bac5ef1f3 (patch) | |
| tree | a78790a36fe39675100f9a0886c8a88450516c8f | |
| parent | d9ecc911ffc5f2d961a8c96129bafbb8d16a17f7 (diff) | |
| download | emacs-eb708e87ade8035dfa454097f63a6f1bac5ef1f3.tar.gz emacs-eb708e87ade8035dfa454097f63a6f1bac5ef1f3.zip | |
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| 1 | @setfilename LNEWS | ||
| 2 | |||
| 3 | @section New Features in the Lisp Language | ||
| 4 | |||
| 5 | @end itemize | ||
| 6 | @itemize @bullet | ||
| 7 | @item | ||
| 8 | The new function @code{delete} is a traditional Lisp function. It takes | ||
| 9 | two arguments, @var{elt} and @var{list}, and deletes from @var{list} any | ||
| 10 | elements that are equal to @var{elt}. It uses the function @code{equal} | ||
| 11 | to compare elements with @var{elt}. | ||
| 12 | |||
| 13 | @item | ||
| 14 | The new function @code{member} is a traditional Lisp function. It takes | ||
| 15 | two arguments, @var{elt} and @var{list}, and finds the first element of | ||
| 16 | @var{list} that is equal to @var{elt}. It uses the function | ||
| 17 | @code{equal} to compare each list element with @var{elt}. | ||
| 18 | |||
| 19 | The value is a sublist of @var{list}, whose first element is the one | ||
| 20 | that was found. If no matching element is found, the value is | ||
| 21 | @code{nil}. | ||
| 22 | |||
| 23 | @ignore @c Seems not to be true, from looking at the code. | ||
| 24 | @item | ||
| 25 | The function @code{equal} is now more robust: it does not crash due to | ||
| 26 | circular list structure. | ||
| 27 | @end ignore | ||
| 28 | |||
| 29 | @item | ||
| 30 | The new function @code{indirect-function} finds the effective function | ||
| 31 | definition of an object called as a function. If the object is a | ||
| 32 | symbol, @code{indirect-function} looks in the function definition of the | ||
| 33 | symbol. It keeps doing this until it finds something that is not a | ||
| 34 | symbol. | ||
| 35 | |||
| 36 | @item | ||
| 37 | There are new escape sequences for use in character and string | ||
| 38 | constants. The escape sequence @samp{\a} is equivalent to @samp{\C-g}, | ||
| 39 | the @sc{ASCII} @sc{BEL} character (code 7). The escape sequence | ||
| 40 | @samp{\x} followed by a hexidecimal number represents the character | ||
| 41 | whose @sc{ASCII} code is that number. There is no limit on the number | ||
| 42 | of digits in the hexidecimal value. | ||
| 43 | |||
| 44 | @item | ||
| 45 | The function @code{read} when reading from a buffer now does not skip a | ||
| 46 | terminator character that terminates a symbol. It leaves that character | ||
| 47 | to be read (or just skipped, if it is whitespace) next time. | ||
| 48 | |||
| 49 | @item | ||
| 50 | When you use a function @var{function} as the input stream for | ||
| 51 | @code{read}, it is usually called with no arguments, and should return | ||
| 52 | the next character. In Emacs 19, sometimes @var{function} is called | ||
| 53 | with one argument (always a character). When that happens, | ||
| 54 | @var{function} should save the argument and arrange to return it when | ||
| 55 | called next time. | ||
| 56 | |||
| 57 | @item | ||
| 58 | @code{random} with integer argument @var{n} returns a random number | ||
| 59 | between 0 and @var{n}@minus{}1. | ||
| 60 | |||
| 61 | @item | ||
| 62 | The functions @code{documentation} and @code{documentation-property} now | ||
| 63 | take an additional optional argument which, if non-@code{nil}, says to | ||
| 64 | refrain from calling @code{substitute-command-keys}. This way, you get | ||
| 65 | the exact text of the documentation string as written, without the usual | ||
| 66 | substitutions. Make sure to call @code{substitute-command-keys} | ||
| 67 | yourself if you decide to display the string. | ||
| 68 | |||
| 69 | @ignore | ||
| 70 | @item | ||
| 71 | The new function @code{invocation-name} returns as a string the program | ||
| 72 | name that was used to run Emacs, with any directory names discarded. | ||
| 73 | @c ??? This hasn't been written yet. ??? | ||
| 74 | @end ignore | ||
| 75 | |||
| 76 | @item | ||
| 77 | The new function @code{map-y-or-n-p} makes it convenient to ask a series | ||
| 78 | of similar questions. The arguments are @var{prompter}, @var{actor}, | ||
| 79 | @var{list}, and optional @var{help}. | ||
| 80 | |||
| 81 | The value of @var{list} is a list of objects, or a function of no | ||
| 82 | arguments to return either the next object or @code{nil} meaning there | ||
| 83 | are no more. | ||
| 84 | |||
| 85 | The argument @var{prompter} specifies how to ask each question. If | ||
| 86 | @var{prompter} is a string, the question text is computed like this: | ||
| 87 | |||
| 88 | @example | ||
| 89 | (format @var{prompter} @var{object}) | ||
| 90 | @end example | ||
| 91 | |||
| 92 | @noindent | ||
| 93 | where @var{object} is the next object to ask about. | ||
| 94 | |||
| 95 | If not a string, @var{prompter} should be a function of one argument | ||
| 96 | (the next object to ask about) and should return the question text. | ||
| 97 | |||
| 98 | The argument @var{actor} should be a function of one argument, which is | ||
| 99 | called with each object that the user says yes for. Its argument is | ||
| 100 | always one object from @var{list}. | ||
| 101 | |||
| 102 | If @var{help} is given, it is a list @code{(@var{object} @var{objects} | ||
| 103 | @var{action})}, where @var{object} is a string containing a singular | ||
| 104 | noun that describes the objects conceptually being acted on; | ||
| 105 | @var{objects} is the corresponding plural noun and @var{action} is a | ||
| 106 | transitive verb describing @var{actor}. The default is @code{("object" | ||
| 107 | "objects" "act on")}. | ||
| 108 | |||
| 109 | Each time a question is asked, the user may enter @kbd{y}, @kbd{Y}, or | ||
| 110 | @key{SPC} to act on that object; @kbd{n}, @kbd{N}, or @key{DEL} to skip | ||
| 111 | that object; @kbd{!} to act on all following objects; @key{ESC} or | ||
| 112 | @kbd{q} to exit (skip all following objects); @kbd{.} (period) to act on | ||
| 113 | the current object and then exit; or @kbd{C-h} to get help. | ||
| 114 | |||
| 115 | @code{map-y-or-n-p} returns the number of objects acted on. | ||
| 116 | |||
| 117 | @item | ||
| 118 | You can now ``set'' environment variables with the @code{setenv} | ||
| 119 | command. This works by setting the variable @code{process-environment}, | ||
| 120 | which @code{getenv} now examines in preference to the environment Emacs | ||
| 121 | received from its parent. | ||
| 122 | @end itemize | ||
| 123 | |||
| 124 | @section New Features for Loading Libraries | ||
| 125 | |||
| 126 | You can now arrange to run a hook if a particular Lisp library is | ||
| 127 | loaded. | ||
| 128 | |||
| 129 | The variable @code{after-load-alist} is an alist of expressions to be | ||
| 130 | evalled when particular files are loaded. Each element looks like | ||
| 131 | @code{(@var{filename} @var{forms}@dots{})}. | ||
| 132 | |||
| 133 | When @code{load} is run and the file name argument equals | ||
| 134 | @var{filename}, the @var{forms} in the corresponding element are | ||
| 135 | executed at the end of loading. @var{filename} must match exactly! | ||
| 136 | Normally @var{filename} is the name of a library, with no directory | ||
| 137 | specified, since that is how @code{load} is normally called. | ||
| 138 | |||
| 139 | An error in @var{forms} does not undo the load, but does prevent | ||
| 140 | execution of the rest of the @var{forms}. | ||
| 141 | |||
| 142 | The function @code{eval-after-load} provides a convenient way to add | ||
| 143 | entries to the alist. Call it with two arguments, @var{file} and a | ||
| 144 | form to execute. | ||
| 145 | |||
| 146 | The function @code{autoload} now supports autoloading a keymap. | ||
| 147 | Use @code{keymap} as the fourth argument if the autoloaded function | ||
| 148 | will become a keymap when loaded. | ||
| 149 | |||
| 150 | There is a new feature for specifying which functions in a library should | ||
| 151 | be autoloaded by writing special ``magic'' comments in that library itself. | ||
| 152 | |||
| 153 | Write @samp{;;;###autoload} on a line by itself before a function | ||
| 154 | definition before the real definition of the function, in its | ||
| 155 | autoloadable source file; then the command @kbd{M-x | ||
| 156 | update-file-autoloads} automatically puts the @code{autoload} call into | ||
| 157 | @file{loaddefs.el}. | ||
| 158 | |||
| 159 | You can also put other kinds of forms into @file{loaddefs.el}, by | ||
| 160 | writing @samp{;;;###autoload} followed on the same line by the form. | ||
| 161 | @kbd{M-x update-file-autoloads} copies the form from that line. | ||
| 162 | |||
| 163 | @section Compilation Features | ||
| 164 | |||
| 165 | @itemize @bullet | ||
| 166 | @item | ||
| 167 | Inline functions. | ||
| 168 | |||
| 169 | You can define an @dfn{inline function} with @code{defsubst}. Use | ||
| 170 | @code{defsubst} just like @code{defun}, and it defines a function which | ||
| 171 | you can call in all the usual ways. Whenever the function thus defined | ||
| 172 | is used in compiled code, the compiler will open code it. | ||
| 173 | |||
| 174 | You can get somewhat the same effects with a macro, but a macro has the | ||
| 175 | limitation that you can use it only explicitly; a macro cannot be called | ||
| 176 | with @code{apply}, @code{mapcar} and so on. Also, it takes some work to | ||
| 177 | convert an ordinary function into a macro. To convert it into an inline | ||
| 178 | function, simply replace @code{defun} with @code{defsubst}. | ||
| 179 | |||
| 180 | Making a function inline makes explicit calls run faster. But it also | ||
| 181 | has disadvantages. For one thing, it reduces flexibility; if you change | ||
| 182 | the definition of the function, calls already inlined still use the old | ||
| 183 | definition until you recompile them. | ||
| 184 | |||
| 185 | Another disadvantage is that making a large function inline can increase | ||
| 186 | the size of compiled code both in files and in memory. Since the | ||
| 187 | advantages of inline functions are greatest for small functions, you | ||
| 188 | generally should not make large functions inline. | ||
| 189 | |||
| 190 | Inline functions can be used and open coded later on in the same file, | ||
| 191 | following the definition, just like macros. | ||
| 192 | |||
| 193 | @item | ||
| 194 | The command @code{byte-compile-file} now offers to save any buffer | ||
| 195 | visiting the file you are compiling. | ||
| 196 | |||
| 197 | @item | ||
| 198 | The new command @code{compile-defun} reads, compiles and executes the | ||
| 199 | defun containing point. If you use this on a defun that is actually a | ||
| 200 | function definition, the effect is to install a compiled version of | ||
| 201 | that function. | ||
| 202 | |||
| 203 | @item | ||
| 204 | Whenever you load a Lisp file or library, you now receive a warning if | ||
| 205 | the directory contains both a @samp{.el} file and a @samp{.elc} file, | ||
| 206 | and the @samp{.el} file is newer. This typically indicates that someone | ||
| 207 | has updated the Lisp code but forgotten to recompile it, so the changes | ||
| 208 | do not take effect. The warning is a reminder to recompile. | ||
| 209 | |||
| 210 | @item | ||
| 211 | The special form @code{eval-when-compile} marks the forms it contains to | ||
| 212 | be evaluated at compile time @emph{only}. At top-level, this is | ||
| 213 | analogous to the Common Lisp idiom @code{(eval-when (compile) | ||
| 214 | @dots{})}. Elsewhere, it is similar to the Common Lisp @samp{#.} reader | ||
| 215 | macro (but not when interpreting). | ||
| 216 | |||
| 217 | If you're thinking of using this feature, we recommend you consider whether | ||
| 218 | @code{provide} and @code{require} might do the job as well. | ||
| 219 | |||
| 220 | @item | ||
| 221 | The special form @code{eval-and-compile} is similar to | ||
| 222 | @code{eval-when-compile}, but the whole form is evaluated both at | ||
| 223 | compile time and at run time. | ||
| 224 | |||
| 225 | If you're thinking of using this feature, we recommend you consider | ||
| 226 | whether @code{provide} and @code{require} might do the job as well. | ||
| 227 | |||
| 228 | @item | ||
| 229 | Emacs Lisp has a new data type for byte-code functions. This makes | ||
| 230 | them faster to call, and also saves space. Internally, a byte-code | ||
| 231 | function object is much like a vector; however, the evaluator handles | ||
| 232 | this data type specially when it appears as a function to be called. | ||
| 233 | |||
| 234 | The printed representation for a byte-code function object is like that | ||
| 235 | for a vector, except that it starts with @samp{#} before the opening | ||
| 236 | @samp{[}. A byte-code function object must have at least four elements; | ||
| 237 | there is no maximum number, but only the first six elements are actually | ||
| 238 | used. They are: | ||
| 239 | |||
| 240 | @table @var | ||
| 241 | @item arglist | ||
| 242 | The list of argument symbols. | ||
| 243 | |||
| 244 | @item byte-code | ||
| 245 | The string containing the byte-code instructions. | ||
| 246 | |||
| 247 | @item constants | ||
| 248 | The vector of constants referenced by the byte code. | ||
| 249 | |||
| 250 | @item stacksize | ||
| 251 | The maximum stack size this function needs. | ||
| 252 | |||
| 253 | @item docstring | ||
| 254 | The documentation string (if any); otherwise, @code{nil}. | ||
| 255 | |||
| 256 | @item interactive | ||
| 257 | The interactive spec (if any). This can be a string or a Lisp | ||
| 258 | expression. It is @code{nil} for a function that isn't interactive. | ||
| 259 | @end table | ||
| 260 | |||
| 261 | The predicate @code{byte-code-function-p} tests whether a given object | ||
| 262 | is a byte-code function. | ||
| 263 | |||
| 264 | You can create a byte-code function object in a Lisp program | ||
| 265 | with the function @code{make-byte-code}. Its arguments are the elements | ||
| 266 | to put in the byte-code function object. | ||
| 267 | |||
| 268 | You should not try to come up with the elements for a byte-code function | ||
| 269 | yourself, because if they are inconsistent, Emacs may crash when you | ||
| 270 | call the function. Always leave it to the byte compiler to create these | ||
| 271 | objects; it, we hope, always makes the elements consistent. | ||
| 272 | @end itemize | ||
| 273 | |||
| 274 | @section Floating Point Numbers | ||
| 275 | |||
| 276 | You can now use floating point numbers in Emacs, if you define the macro | ||
| 277 | @code{LISP_FLOAT_TYPE} when you compile Emacs. | ||
| 278 | |||
| 279 | The printed representation for floating point numbers requires either a | ||
| 280 | decimal point surrounded by digits, or an exponent, or both. For | ||
| 281 | example, @samp{1500.0}, @samp{15e2}, @samp{15.0e2} and @samp{1.5e3} are | ||
| 282 | four ways of writing a floating point number whose value is 1500. | ||
| 283 | |||
| 284 | The existing predicate @code{numberp} now returns @code{t} if the | ||
| 285 | argument is any kind of number---either integer or floating. The new | ||
| 286 | predicates @code{integerp} and @code{floatp} check for specific types of | ||
| 287 | numbers. | ||
| 288 | |||
| 289 | You can do arithmetic on floating point numbers with the ordinary | ||
| 290 | arithmetic functions, @code{+}, @code{-}, @code{*} and @code{/}. If you | ||
| 291 | call one of these functions with both integers and floating point | ||
| 292 | numbers among the arguments, the arithmetic is done in floating point. | ||
| 293 | The same applies to the numeric comparison functions such as @code{=} | ||
| 294 | and @code{<}. The remainder function @code{%} does not accept floating | ||
| 295 | point arguments, and neither do the bitwise boolean operations such as | ||
| 296 | @code{logand} or the shift functions such as @code{ash}. | ||
| 297 | |||
| 298 | There is a new arithmetic function, @code{abs}, which returns the absolute | ||
| 299 | value of its argument. It handles both integers and floating point | ||
| 300 | numbers. | ||
| 301 | |||
| 302 | To convert an integer to floating point, use the function @code{float}. | ||
| 303 | There are four functions to convert floating point numbers to integers; | ||
| 304 | they differ in how they round. @code{truncate} rounds toward 0, | ||
| 305 | @code{floor} rounds down, @code{ceil} rounds up, and @code{round} | ||
| 306 | produces the nearest integer. | ||
| 307 | |||
| 308 | You can use @code{logb} to extract the binary exponent of a floating | ||
| 309 | point number. More precisely, it is the logarithm base 2, rounded down | ||
| 310 | to an integer. | ||
| 311 | |||
| 312 | Emacs has several new mathematical functions that accept any kind of | ||
| 313 | number as argument, but always return floating point numbers. | ||
| 314 | |||
| 315 | @table @code | ||
| 316 | @item cos | ||
| 317 | @findex cos | ||
| 318 | @itemx sin | ||
| 319 | @findex sin | ||
| 320 | @itemx tan | ||
| 321 | @findex tan | ||
| 322 | Trigonometric functions. | ||
| 323 | @item acos | ||
| 324 | @findex acos | ||
| 325 | @itemx asin | ||
| 326 | @findex asin | ||
| 327 | @itemx atan | ||
| 328 | @findex atan | ||
| 329 | Inverse trigonometric functions. | ||
| 330 | @item exp | ||
| 331 | @findex exp | ||
| 332 | The exponential function (power of @var{e}). | ||
| 333 | @item log | ||
| 334 | @findex log | ||
| 335 | Logarithm base @var{e}. | ||
| 336 | @item expm1 | ||
| 337 | @findex expm1 | ||
| 338 | Power of @var{e}, minus 1. | ||
| 339 | @item log1p | ||
| 340 | @findex log1p | ||
| 341 | Add 1, then take the logarithm. | ||
| 342 | @item log10 | ||
| 343 | @findex log10 | ||
| 344 | Logarithm base 10 | ||
| 345 | @item expt | ||
| 346 | @findex expt | ||
| 347 | Raise @var{x} to power @var{y}. | ||
| 348 | @item sqrt | ||
| 349 | @findex sqrt | ||
| 350 | The square root function. | ||
| 351 | @end table | ||
| 352 | |||
| 353 | The new function @code{string-to-number} now parses a string containing | ||
| 354 | either an integer or a floating point number, returning the number. | ||
| 355 | |||
| 356 | The @code{format} function now handles the specifications @samp{%e}, | ||
| 357 | @samp{%f} and @samp{%g} for printing floating point numbers; likewise | ||
| 358 | @code{message}. | ||
| 359 | |||
| 360 | The new variable @code{float-output-format} controls how Lisp prints | ||
| 361 | floating point numbers. Its value should be @code{nil} or a string. | ||
| 362 | |||
| 363 | If it is a string, it should contain a @samp{%}-spec like those accepted | ||
| 364 | by @code{printf} in C, but with some restrictions. It must start with | ||
| 365 | the two characters @samp{%.}. After that comes an integer which is the | ||
| 366 | precision specification, and then a letter which controls the format. | ||
| 367 | |||
| 368 | The letters allowed are @samp{e}, @samp{f} and @samp{g}. Use @samp{e} | ||
| 369 | for exponential notation (@samp{@var{dig}.@var{digits}e@var{expt}}). | ||
| 370 | Use @samp{f} for decimal point notation | ||
| 371 | (@samp{@var{digits}.@var{digits}}). Use @samp{g} to choose the shorter | ||
| 372 | of those two formats for the number at hand. | ||
| 373 | |||
| 374 | The precision in any of these cases is the number of digits following | ||
| 375 | the decimal point. With @samp{f}, a precision of 0 means to omit the | ||
| 376 | decimal point. 0 is not allowed with @samp{f} or @samp{g}. | ||
| 377 | |||
| 378 | A value of @code{nil} means to use the format @samp{%.20g}. | ||
| 379 | |||
| 380 | No matter what the value of @code{float-output-format}, printing ensures | ||
| 381 | that the result fits the syntax rules for a floating point number. If | ||
| 382 | it doesn't fit (for example, if it looks like an integer), it is | ||
| 383 | modified to fit. By contrast, the @code{format} function formats | ||
| 384 | floating point numbers without requiring the output to fit the | ||
| 385 | syntax rules for floating point number. | ||
| 386 | |||
| 387 | @section New Features for Printing And Formatting Output | ||
| 388 | |||
| 389 | @itemize @bullet | ||
| 390 | @item | ||
| 391 | The @code{format} function has a new feature: @samp{%S}. This print | ||
| 392 | spec prints any kind of Lisp object, even a string, using its Lisp | ||
| 393 | printed representation. | ||
| 394 | |||
| 395 | By contrast, @samp{%s} prints everything without quotation. | ||
| 396 | |||
| 397 | @item | ||
| 398 | @code{prin1-to-string} now takes an optional second argument which says | ||
| 399 | not to print the Lisp quotation characters. (In other words, to use | ||
| 400 | @code{princ} instead of @code{prin1}.) | ||
| 401 | |||
| 402 | @item | ||
| 403 | The new variable @code{print-level} specifies the maximum depth of list | ||
| 404 | nesting to print before cutting off all deeper structure. A value of | ||
| 405 | @code{nil} means no limit. | ||
| 406 | @end itemize | ||
| 407 | |||
| 408 | @section Changes in Basic Editing Functions | ||
| 409 | |||
| 410 | @itemize @bullet | ||
| 411 | @item | ||
| 412 | There are two new primitives for putting text in the kill ring: | ||
| 413 | @code{kill-new} and @code{kill-append}. | ||
| 414 | |||
| 415 | The function @code{kill-new} adds a string to the front of the kill ring. | ||
| 416 | |||
| 417 | Use @code{kill-append} to add a string to a previous kill. The second | ||
| 418 | argument @var{before-p}, if non-@code{nil}, says to add the string at | ||
| 419 | the beginning; otherwise, it goes at the end. | ||
| 420 | |||
| 421 | Both of these functions apply @code{interprogram-cut-function} to the | ||
| 422 | entire string of killed text that ends up at the beginning of the kill | ||
| 423 | ring. | ||
| 424 | |||
| 425 | @item | ||
| 426 | The new function @code{current-kill} rotates the yanking pointer in the | ||
| 427 | kill ring by @var{n} places, and returns the text at that place in the | ||
| 428 | ring. If the optional second argument @var{do-not-move} is | ||
| 429 | non-@code{nil}, it doesn't actually move the yanking point; it just | ||
| 430 | returns the @var{n}th kill forward. If @var{n} is zero, indicating a | ||
| 431 | request for the latest kill, @code{current-kill} calls | ||
| 432 | @code{interprogram-paste-function} (documented below) before consulting | ||
| 433 | the kill ring. | ||
| 434 | |||
| 435 | All Emacs Lisp programs should either use @code{current-kill}, | ||
| 436 | @code{kill-new}, and @code{kill-append} to manipulate the kill ring, or | ||
| 437 | be sure to call @code{interprogram-paste-function} and | ||
| 438 | @code{interprogram-cut-function} as appropriate. | ||
| 439 | |||
| 440 | @item | ||
| 441 | The variables @code{interprogram-paste-function} and | ||
| 442 | @code{interprogram-cut-function} exist so that you can provide functions | ||
| 443 | to transfer killed text to and from other programs. | ||
| 444 | |||
| 445 | @item | ||
| 446 | The @code{kill-region} function can now be used in read-only buffers. | ||
| 447 | It beeps, but adds the region to the kill ring without deleting it. | ||
| 448 | |||
| 449 | @item | ||
| 450 | The new function @code{compare-buffer-substrings} lets you compare two | ||
| 451 | substrings of the same buffer or two different buffers. Its arguments | ||
| 452 | look like this: | ||
| 453 | |||
| 454 | @example | ||
| 455 | (compare-buffer-substrings @var{buf1} @var{beg1} @var{end1} @var{buf2} @var{beg2} @var{end2}) | ||
| 456 | @end example | ||
| 457 | |||
| 458 | The first three arguments specify one substring, giving a buffer and two | ||
| 459 | positions within the buffer. The last three arguments specify the other | ||
| 460 | substring in the same way. | ||
| 461 | |||
| 462 | The value is negative if the first substring is less, positive if the | ||
| 463 | first is greater, and zero if they are equal. The absolute value of | ||
| 464 | the result is one plus the index of the first different characters. | ||
| 465 | |||
| 466 | @item | ||
| 467 | Overwrite mode treats tab and newline characters specially. You can now | ||
| 468 | turn off this special treatment by setting @code{overwrite-binary-mode} | ||
| 469 | to @code{t}. | ||
| 470 | |||
| 471 | @item | ||
| 472 | Once the mark ``exists'' in a buffer, it normally never ceases to | ||
| 473 | exist. However, it may become @dfn{inactive}. The variable | ||
| 474 | @code{mark-active}, which is always local in all buffers, indicates | ||
| 475 | whether the mark is active: non-@code{nil} means yes. | ||
| 476 | |||
| 477 | A command can request deactivation of the mark upon return to the editor | ||
| 478 | command loop by setting @code{deactivate-mark} to a non-@code{nil} | ||
| 479 | value. Transient Mark mode works by causing the buffer modification | ||
| 480 | primitives to set @code{deactivate-mark}. | ||
| 481 | |||
| 482 | The variables @code{activate-mark-hook} and @code{deactivate-mark-hook} | ||
| 483 | are normal hooks run, respectively, when the mark becomes active andwhen | ||
| 484 | it becomes inactive. The hook @code{activate-mark-hook} is also run at | ||
| 485 | the end of a command if the mark is active and the region may have | ||
| 486 | changed. | ||
| 487 | |||
| 488 | @item | ||
| 489 | The function @code{move-to-column} now accepts a second optional | ||
| 490 | argument @var{force}, in addition to @var{column}; if the requested | ||
| 491 | column @var{column} is in the middle of a tab character and @var{force} | ||
| 492 | is non-@code{nil}, @code{move-to-column} replaces the tab with the | ||
| 493 | appropriate sequence of spaces so that it can place point exactly at | ||
| 494 | @var{column}. | ||
| 495 | |||
| 496 | @item | ||
| 497 | The search functions when successful now return the value of point | ||
| 498 | rather than just @code{t}. This affects the functions | ||
| 499 | @code{search-forward}, @code{search-backward}, | ||
| 500 | @code{word-search-forward}, @code{word-search-backward}, | ||
| 501 | @code{re-search-forward}, and @code{re-search-backward}. | ||
| 502 | |||
| 503 | @item | ||
| 504 | When you do regular expression searching or matching, there is no longer | ||
| 505 | a limit to how many @samp{\(@dots{}\)} pairs you can get information | ||
| 506 | about with @code{match-beginning} and @code{match-end}. Also, these | ||
| 507 | parenthetical groupings may now be nested to any degree. | ||
| 508 | |||
| 509 | @item | ||
| 510 | The new special form @code{save-match-data} preserves the regular | ||
| 511 | expression match status. Usage: @code{(save-match-data | ||
| 512 | @var{body}@dots{})}. | ||
| 513 | |||
| 514 | @item | ||
| 515 | The function @code{translate-region} applies a translation table to the | ||
| 516 | characters in a part of the buffer. Invoke it as | ||
| 517 | @code{(translate-region @var{start} @var{end} @var{table})}; @var{start} | ||
| 518 | and @var{end} bound the region to translate. | ||
| 519 | |||
| 520 | The translation table @var{table} is a string; @code{(aref @var{table} | ||
| 521 | @var{ochar})} gives the translated character corresponding to | ||
| 522 | @var{ochar}. If the length of @var{table} is less than 256, any | ||
| 523 | characters with codes larger than the length of @var{table} are not | ||
| 524 | altered by the translation. | ||
| 525 | |||
| 526 | @code{translate-region} returns the number of characters which were | ||
| 527 | actually changed by the translation. This does not count characters | ||
| 528 | which were mapped into themselves in the translation table. | ||
| 529 | |||
| 530 | @item | ||
| 531 | There are two new hook variables that let you notice all changes in all | ||
| 532 | buffers (or in a particular buffer, if you make them buffer-local): | ||
| 533 | @code{before-change-function} and @code{after-change-function}. | ||
| 534 | |||
| 535 | If @code{before-change-function} is non-@code{nil}, then it is called | ||
| 536 | before any buffer modification. Its arguments are the beginning and end | ||
| 537 | of the region that is going to change, represented as integers. The | ||
| 538 | buffer that's about to change is always the current buffer. | ||
| 539 | |||
| 540 | If @code{after-change-function} is non-@code{nil}, then it is called | ||
| 541 | after any buffer modification. It takes three arguments: the beginning | ||
| 542 | and end of the region just changed, and the length of the text that | ||
| 543 | existed before the change. (To get the current length, subtract the | ||
| 544 | rrgion beginning from the region end.) All three arguments are | ||
| 545 | integers. The buffer that's about to change is always the current | ||
| 546 | buffer. | ||
| 547 | |||
| 548 | Both of these variables are temporarily bound to @code{nil} during the | ||
| 549 | time that either of these hooks is running. This means that if one of | ||
| 550 | these functions changes the buffer, that change won't run these | ||
| 551 | functions. If you do want hooks to be run recursively, write your hook | ||
| 552 | functions to bind these variables back to their usual values. | ||
| 553 | |||
| 554 | @item | ||
| 555 | The hook @code{first-change-hook} is run using @code{run-hooks} whenever | ||
| 556 | a buffer is changed that was previously in the unmodified state. | ||
| 557 | |||
| 558 | @item | ||
| 559 | The second argument to @code{insert-abbrev-table-description} is | ||
| 560 | now optional. | ||
| 561 | @end itemize | ||
| 562 | |||
| 563 | @section Text Properties | ||
| 564 | |||
| 565 | Each character in a buffer or a string can have a @dfn{text property | ||
| 566 | list}, much like the property list of a symbol. The properties belong | ||
| 567 | to a particular character at a particular place, such as, the letter | ||
| 568 | @samp{T} at the beginning of this sentence. Each property has a name, | ||
| 569 | which is usually a symbol, and an associated value, which can be any | ||
| 570 | Lisp object---just as for properties of symbols (@pxref{Property Lists}). | ||
| 571 | |||
| 572 | You can use the property @code{face-code} to control the font and | ||
| 573 | color of text. That is the only property name which currently has a | ||
| 574 | special meaning, but you can create properties of any name and examine | ||
| 575 | them later for your own purposes. | ||
| 576 | |||
| 577 | Copying text between strings and buffers preserves the properties | ||
| 578 | along with the characters; this includes such diverse functions as | ||
| 579 | @code{substring}, @code{insert}, and @code{buffer-substring}. | ||
| 580 | |||
| 581 | Since text properties are considered part of the buffer contents, | ||
| 582 | changing properties in a buffer ``modifies'' the buffer, and you can | ||
| 583 | also undo such changes. | ||
| 584 | |||
| 585 | Strings with text properties have a special printed representation | ||
| 586 | which describes all the properties. This representation is also the | ||
| 587 | read syntax for such a string. It looks like this: | ||
| 588 | |||
| 589 | @example | ||
| 590 | #("@var{characters}" @var{property-data}...) | ||
| 591 | @end example | ||
| 592 | |||
| 593 | @noindent | ||
| 594 | where @var{property-data} is zero or more elements in groups of three as | ||
| 595 | follows: | ||
| 596 | |||
| 597 | @example | ||
| 598 | @var{beg} @var{end} @var{plist} | ||
| 599 | @end example | ||
| 600 | |||
| 601 | @noindent | ||
| 602 | The elements @var{beg} and @var{end} are integers, and together specify | ||
| 603 | a portion of the string; @var{plist} is the property list for that | ||
| 604 | portion. | ||
| 605 | |||
| 606 | @subsection Examining Text Properties | ||
| 607 | |||
| 608 | The simplest way to examine text properties is to ask for the value of | ||
| 609 | a particular property of a particular character. For that, use | ||
| 610 | @code{get-text-property}. Use @code{text-properties-at} to get the | ||
| 611 | entire property list of a character. @xref{Property Search}, for | ||
| 612 | functions to examine the properties of a number of characters at once. | ||
| 613 | |||
| 614 | @code{(get-text-property @var{pos} @var{prop} @var{object})} returns the | ||
| 615 | @var{prop} property of the character after @var{pos} in @var{object} (a | ||
| 616 | buffer or string). The argument @var{object} is optional and defaults | ||
| 617 | to the current buffer. | ||
| 618 | |||
| 619 | @code{(text-properties-at @var{pos} @var{object})} returns the entire | ||
| 620 | property list of the character after @var{pos} in the string or buffer | ||
| 621 | @var{object} (which defaults to the current buffer). | ||
| 622 | |||
| 623 | @subsection Changing Text Properties | ||
| 624 | |||
| 625 | There are three primitives for changing properties of a specified | ||
| 626 | range of text: | ||
| 627 | |||
| 628 | @table @code | ||
| 629 | @item add-text-properties | ||
| 630 | This function puts on specified properties, leaving other existing | ||
| 631 | properties unaltered. | ||
| 632 | |||
| 633 | @item put-text-property | ||
| 634 | This function puts on a single specified property, leaving others | ||
| 635 | unaltered. | ||
| 636 | |||
| 637 | @item remove-text-properties | ||
| 638 | This function removes specified properties, leaving other | ||
| 639 | properties unaltered. | ||
| 640 | |||
| 641 | @item set-text-properties | ||
| 642 | This function replaces the entire property list, leaving no vessage of | ||
| 643 | the properties that that text used to have. | ||
| 644 | @end table | ||
| 645 | |||
| 646 | All these functions take four arguments: @var{start}, @var{end}, | ||
| 647 | @var{props}, and @var{object}. The last argument is optional and | ||
| 648 | defaults to the current buffer. The argument @var{props} has the form | ||
| 649 | of a property list. | ||
| 650 | |||
| 651 | @subsection Property Search Functions | ||
| 652 | |||
| 653 | In typical use of text properties, most of the time several or many | ||
| 654 | consecutive characters have the same value for a property. Rather than | ||
| 655 | writing your programs to examine characters one by one, it is much | ||
| 656 | faster to process chunks of text that have the same property value. | ||
| 657 | |||
| 658 | The functions @code{next-property-change} and | ||
| 659 | @code{previous-property-change} scan forward or backward from position | ||
| 660 | @var{pos} in @var{object}, looking for a change in any property between | ||
| 661 | two characters scanned. They returns the position between those two | ||
| 662 | characters, or @code{nil} if no change is found. | ||
| 663 | |||
| 664 | The functions @code{next-single-property-change} and | ||
| 665 | @code{previous-single-property-change} are similar except that you | ||
| 666 | specify a particular property and they look for changes in the value of | ||
| 667 | that property only. The property is the second argument, and | ||
| 668 | @var{object} is third. | ||
| 669 | |||
| 670 | @subsection Special Properties | ||
| 671 | |||
| 672 | If a character has a @code{category} property, we call it the | ||
| 673 | @dfn{category} of the character. It should be a symbol. The properties | ||
| 674 | of the symbol serve as defaults for the properties of the character. | ||
| 675 | |||
| 676 | You can use the property @code{face-code} to control the font and | ||
| 677 | color of text. That is the only property name which currently has a | ||
| 678 | special meaning, but you can create properties of any name and examine | ||
| 679 | them later for your own purposes. | ||
| 680 | about face codes. | ||
| 681 | |||
| 682 | You can specify a different keymap for a portion of the text by means | ||
| 683 | of a @code{local-map} property. The property's value, for the character | ||
| 684 | after point, replaces the buffer's local map. | ||
| 685 | |||
| 686 | If a character has the property @code{read-only}, then modifying that | ||
| 687 | character is not allowed. Any command that would do so gets an error. | ||
| 688 | |||
| 689 | If a character has the property @code{modification-hooks}, then its | ||
| 690 | value should be a list of functions; modifying that character calls all | ||
| 691 | of those functions. Each function receives two arguments: the beginning | ||
| 692 | and end of the part of the buffer being modified. Note that if a | ||
| 693 | particular modification hook function appears on several characters | ||
| 694 | being modified by a single primitive, you can't predict how many times | ||
| 695 | the function will be called. | ||
| 696 | |||
| 697 | Insertion of text does not, strictly speaking, change any existing | ||
| 698 | character, so there is a special rule for insertion. It compares the | ||
| 699 | @code{read-only} properties of the two surrounding characters; if they | ||
| 700 | are @code{eq}, then the insertion is not allowed. Assuming insertion is | ||
| 701 | allowed, it then gets the @code{modification-hooks} properties of those | ||
| 702 | characters and calls all the functions in each of them. (If a function | ||
| 703 | appears on both characters, it may be called once or twice.) | ||
| 704 | |||
| 705 | The special properties @code{point-entered} and @code{point-left} | ||
| 706 | record hook functions that report motion of point. Each time point | ||
| 707 | moves, Emacs compares these two property values: | ||
| 708 | |||
| 709 | @itemize @bullet | ||
| 710 | @item | ||
| 711 | the @code{point-left} property of the character after the old location, | ||
| 712 | and | ||
| 713 | @item | ||
| 714 | the @code{point-entered} property of the character after the new | ||
| 715 | location. | ||
| 716 | @end itemize | ||
| 717 | |||
| 718 | @noindent | ||
| 719 | If these two values differ, each of them is called (if not @code{nil}) | ||
| 720 | with two arguments: the old value of point, and the new one. | ||
| 721 | |||
| 722 | The same comparison is made for the characters before the old and new | ||
| 723 | locations. The result may be to execute two @code{point-left} functions | ||
| 724 | (which may be the same function) and/or two @code{point-entered} | ||
| 725 | functions (which may be the same function). The @code{point-left} | ||
| 726 | functions are always called before the @code{point-entered} functions. | ||
| 727 | |||
| 728 | A primitive function may examine characters at various positions | ||
| 729 | without moving point to those positions. Only an actual change in the | ||
| 730 | value of point runs these hook functions. | ||
| 731 | |||
| 732 | @section New Features for Files | ||
| 733 | |||
| 734 | @itemize @bullet | ||
| 735 | @item | ||
| 736 | The new function @code{file-accessible-directory-p} tells you whether | ||
| 737 | you can open files in a particular directory. Specify as an argument | ||
| 738 | either a directory name or a file name which names a directory file. | ||
| 739 | The function returns @code{t} if you can open existing files in that | ||
| 740 | directory. | ||
| 741 | |||
| 742 | @item | ||
| 743 | The new function @code{file-executable-p} returns @code{t} if its | ||
| 744 | argument is the name of a file you have permission to execute. | ||
| 745 | |||
| 746 | @item | ||
| 747 | The function @code{file-truename} returns the ``true name'' of a | ||
| 748 | specified file. This is the name that you get by following symbolic | ||
| 749 | links until none remain. The argument must be an absolute file name. | ||
| 750 | |||
| 751 | @item | ||
| 752 | New functions @code{make-directory} and @code{delete-directory} create and | ||
| 753 | delete directories. They both take one argument, which is the name of | ||
| 754 | the directory as a file. | ||
| 755 | |||
| 756 | @item | ||
| 757 | The function @code{read-file-name} now takes an additional argument | ||
| 758 | which specifies an initial file name. If you specify this argument, | ||
| 759 | @code{read-file-name} inserts it along with the directory name. It puts | ||
| 760 | the cursor between the directory and the initial file name. | ||
| 761 | |||
| 762 | The user can then use the initial file name unchanged, modify it, or | ||
| 763 | simply kill it with @kbd{C-k}. | ||
| 764 | |||
| 765 | If the variable @code{insert-default-directory} is @code{nil}, then the | ||
| 766 | default directory is not inserted, and the new argument is ignored. | ||
| 767 | |||
| 768 | @item | ||
| 769 | The function @code{file-relative-name} does the inverse of | ||
| 770 | expansion---it tries to return a relative name which is equivalent to | ||
| 771 | @var{filename} when interpreted relative to @var{directory}. (If such a | ||
| 772 | relative name would be longer than the absolute name, it returns the | ||
| 773 | absolute name instead.) | ||
| 774 | |||
| 775 | @item | ||
| 776 | The function @code{file-newest-backup} returns the name of the most | ||
| 777 | recent backup file for @var{filename}, or @code{nil} that file has no | ||
| 778 | backup files. | ||
| 779 | |||
| 780 | @item | ||
| 781 | The list returned by @code{file-attributes} now has 12 elements. The | ||
| 782 | 12th element is the file system number of the file system that the file | ||
| 783 | is in. This element together with the file's inode number, which is the | ||
| 784 | 11th element, give enough information to distinguish any two files on | ||
| 785 | the system---no two files can have the same values for both of these | ||
| 786 | numbers. | ||
| 787 | |||
| 788 | @item | ||
| 789 | The new function @code{set-visited-file-modtime} updates the current | ||
| 790 | buffer's recorded modification time from the visited file's time. | ||
| 791 | |||
| 792 | This is useful if the buffer was not read from the file normally, or | ||
| 793 | if the file itself has been changed for some known benign reason. | ||
| 794 | |||
| 795 | If you give the function an argument, that argument specifies the new | ||
| 796 | value for the recorded modification time. The argument should be a list | ||
| 797 | of the form @code{(@var{high} . @var{low})} or @code{(@var{high} | ||
| 798 | @var{low})} containing two integers, each of which holds 16 bits of the | ||
| 799 | time. (This is the same format that @code[file-attributes} uses to | ||
| 800 | return time values.) | ||
| 801 | |||
| 802 | The new function @code{visited-file-modtime} returns the recorded last | ||
| 803 | modification time, in that same format. | ||
| 804 | |||
| 805 | @item | ||
| 806 | The function @code{directory-files} now takes an optional fourth | ||
| 807 | argument which, if non-@code{nil}, inhibits sorting the file names. | ||
| 808 | Use this if you want the utmost possible speed and don't care what order | ||
| 809 | the files are processed in. | ||
| 810 | |||
| 811 | If the order of processing is at all visible to the user, then the user | ||
| 812 | will probably be happier if you do sort the names. | ||
| 813 | |||
| 814 | @item | ||
| 815 | The variable @code{directory-abbrev-alist} contains an alist of | ||
| 816 | abbreviations to use for file directories. Each element has the form | ||
| 817 | @code{(@var{from} . @var{to})}, and says to replace @var{from} with | ||
| 818 | @var{to} when it appears in a directory name. This replacement is done | ||
| 819 | when setting up the default directory of a newly visited file. The | ||
| 820 | @var{from} string is actually a regular expression; it should always | ||
| 821 | start with @samp{^}. | ||
| 822 | |||
| 823 | You can set this variable in @file{site-init.el} to describe the | ||
| 824 | abbreviations appropriate for your site. | ||
| 825 | |||
| 826 | @item | ||
| 827 | The function @code{abbreviate-file-name} applies abbreviations from | ||
| 828 | @code{directory-abbrev-alist} to its argument, and substitutes @samp{~} | ||
| 829 | for the user's home directory. | ||
| 830 | |||
| 831 | Abbreviated directory names are useful for directories that are normally | ||
| 832 | accessed through symbolic links. If you think of the link's name as | ||
| 833 | ``the name'' of the directory, you can define it as an abbreviation for | ||
| 834 | the directory's official name; then ordinarily Emacs will call that | ||
| 835 | directory by the link name you normally use. | ||
| 836 | |||
| 837 | @item | ||
| 838 | @code{write-region} can write a given string instead of text from the | ||
| 839 | buffer. Use the string as the first argument (in place of the | ||
| 840 | starting character position). | ||
| 841 | |||
| 842 | You can supply a second file name as the fifth argument (@var{visit}). | ||
| 843 | Use this to write the data to one file (the first argument, | ||
| 844 | @var{filename}) while nominally visiting a different file (the fifth | ||
| 845 | argument, @var{visit}). The argument @var{visit} is used in the echo | ||
| 846 | area message and also for file locking; @var{visit} is stored in | ||
| 847 | @code{buffer-file-name}. | ||
| 848 | |||
| 849 | @item | ||
| 850 | The value of @code{write-file-hooks} does not change when you switch to | ||
| 851 | a new major mode. The intention is that these hooks have to do with | ||
| 852 | where the file came from, and not with what it contains. | ||
| 853 | |||
| 854 | @item | ||
| 855 | There is a new hook variable for saving files: | ||
| 856 | @code{write-contents-hooks}. It works just like @code{write-file-hooks} | ||
| 857 | except that switching to a new major mode clears it back to @code{nil}. | ||
| 858 | Major modes should use this hook variable rather than | ||
| 859 | @code{write-file-hooks}. | ||
| 860 | |||
| 861 | @item | ||
| 862 | The hook @code{after-save-hook} runs just after a buffer has been saved | ||
| 863 | in its visited file. | ||
| 864 | |||
| 865 | @item | ||
| 866 | The new function @code{set-default-file-modes} sets the file protection | ||
| 867 | for new files created with Emacs. The argument must be an integer. (It | ||
| 868 | would be better to permit symbolic arguments like the @code{chmod} | ||
| 869 | program, but that would take more work than this function merits.) | ||
| 870 | |||
| 871 | Use the new function @code{default-file-modes} to read the current | ||
| 872 | default file mode. | ||
| 873 | |||
| 874 | @item | ||
| 875 | Call the new function @code{unix-sync} to force all pending disk output | ||
| 876 | to happen as soon as possible. | ||
| 877 | @end itemize | ||
| 878 | |||
| 879 | @section Making Certain File Names ``Magic'' | ||
| 880 | |||
| 881 | You can implement special handling for a class of file names. You must | ||
| 882 | supply a regular expression to define the class of names (all those | ||
| 883 | which match the regular expression), plus a handler that implements all | ||
| 884 | the primitive Emacs file operations for file names that do match. | ||
| 885 | |||
| 886 | The value of @code{file-name-handler-alist} is a list of handlers, | ||
| 887 | together with regular expressions that decide when to apply each | ||
| 888 | handler. Each element has the form @code{(@var{regexp} | ||
| 889 | . @var{handler})}. If a file name matches @var{regexp}, then all work | ||
| 890 | on that file is done by calling @var{handler}. | ||
| 891 | |||
| 892 | All the Emacs primitives for file access and file name transformation | ||
| 893 | check the given file name against @code{file-name-handler-alist}, and | ||
| 894 | call @var{handler} to do the work if appropriate. The first argument | ||
| 895 | given to @var{handler} is the name of the primitive; the remaining | ||
| 896 | arguments are the arguments that were passed to that primitive. (The | ||
| 897 | first of these arguments is typically the file name itself.) For | ||
| 898 | example, if you do this: | ||
| 899 | |||
| 900 | @example | ||
| 901 | (file-exists-p @var{filename}) | ||
| 902 | @end example | ||
| 903 | |||
| 904 | @noindent | ||
| 905 | and @var{filename} has handler @var{handler}, then @var{handler} is | ||
| 906 | called like this: | ||
| 907 | |||
| 908 | @example | ||
| 909 | (funcall @var{handler} 'file-exists-p @var{filename}) | ||
| 910 | @end example | ||
| 911 | |||
| 912 | Here are the primitives that you can handle in this way: | ||
| 913 | |||
| 914 | @quotation | ||
| 915 | @code{add-name-to-file}, @code{copy-file}, @code{delete-directory}, | ||
| 916 | @code{delete-file}, @code{directory-file-name}, @code{directory-files}, | ||
| 917 | @code{dired-compress-file}, @code{dired-uncache}, | ||
| 918 | @code{expand-file-name}, @code{file-accessible-directory-p}, | ||
| 919 | @code{file-attributes}, @code{file-directory-p}, | ||
| 920 | @code{file-executable-p}, @code{file-exists-p}, @code{file-local-copy}, | ||
| 921 | @code{file-modes}, @code{file-name-all-completions}, | ||
| 922 | @code{file-name-as-directory}, @code{file-name-completion}, | ||
| 923 | @code{file-name-directory}, @code{file-name-nondirectory}, | ||
| 924 | @code{file-name-sans-versions}, @code{file-newer-than-file-p}, | ||
| 925 | @code{file-readable-p}, @code{file-symlink-p}, @code{file-writable-p}, | ||
| 926 | @code{insert-directory}, @code{insert-file-contents}, | ||
| 927 | @code{make-directory}, @code{make-symbolic-link}, @code{rename-file}, | ||
| 928 | @code{set-file-modes}, @code{verify-visited-file-modtime}, | ||
| 929 | @code{write-region}. | ||
| 930 | @end quotation | ||
| 931 | |||
| 932 | The handler function must handle all of the above operations, and | ||
| 933 | possibly others to be added in the future. Therefore, it should always | ||
| 934 | reinvoke the ordinary Lisp primitive when it receives an operation it | ||
| 935 | does not recognize. Here's one way to do this: | ||
| 936 | |||
| 937 | @smallexample | ||
| 938 | (defun my-file-handler (primitive &rest args) | ||
| 939 | ;; @r{First check for the specific operations} | ||
| 940 | ;; @r{that we have special handling for.} | ||
| 941 | (cond ((eq operation 'insert-file-contents) @dots{}) | ||
| 942 | ((eq operation 'write-region) @dots{}) | ||
| 943 | @dots{} | ||
| 944 | ;; @r{Handle any operation we don't know about.} | ||
| 945 | (t (let (file-name-handler-alist) | ||
| 946 | (apply operation args))))) | ||
| 947 | @end smallexample | ||
| 948 | |||
| 949 | The function @code{file-local-copy} copies file @var{filename} to the | ||
| 950 | local site, if it isn't there already. If @var{filename} specifies a | ||
| 951 | ``magic'' file name which programs outside Emacs cannot directly read or | ||
| 952 | write, this copies the contents to an ordinary file and returns that | ||
| 953 | file's name. | ||
| 954 | |||
| 955 | If @var{filename} is an ordinary file name, not magic, then this function | ||
| 956 | does nothing and returns @code{nil}. | ||
| 957 | |||
| 958 | The function @code{unhandled-file-name-directory} is used to get a | ||
| 959 | non-magic directory name from an arbitrary file name. It uses the | ||
| 960 | directory part of the specified file name if that is not magic. | ||
| 961 | Otherwise, it asks the file name's handler what to do. | ||
| 962 | |||
| 963 | @section Frames | ||
| 964 | @cindex frame | ||
| 965 | |||
| 966 | Emacs now supports multiple X windows via a new data type known as a | ||
| 967 | @dfn{frame}. | ||
| 968 | |||
| 969 | A frame is a rectangle on the screen that contains one or more Emacs | ||
| 970 | windows. Subdividing a frame works just like subdividing the screen in | ||
| 971 | earlier versions of Emacs. | ||
| 972 | |||
| 973 | @cindex terminal frame | ||
| 974 | There are two kinds of frames: terminal frames and X window frames. | ||
| 975 | Emacs creates one terminal frame when it starts up with no X display; it | ||
| 976 | uses Termcap or Terminfo to display using characters. There is no way | ||
| 977 | to create another terminal frame after startup. If Emacs has an X | ||
| 978 | display, it does not make a terminal frame, and there is none. | ||
| 979 | |||
| 980 | @cindex X window frame | ||
| 981 | When you are using X windows, Emacs starts out with a single X window | ||
| 982 | frame. You can create any number of X window frames using | ||
| 983 | @code{make-frame}. | ||
| 984 | |||
| 985 | Use the predicate @code{framep} to determine whether a given Lisp object | ||
| 986 | is a frame. | ||
| 987 | |||
| 988 | The function @code{redraw-frame} redisplays the entire contents of a | ||
| 989 | given frame. | ||
| 990 | |||
| 991 | @subsection Creating and Deleting Frames | ||
| 992 | |||
| 993 | Use @code{make-frame} to create a new frame (supported under X Windows | ||
| 994 | only). This is the only primitive for creating frames. | ||
| 995 | |||
| 996 | @code{make-frame} takes just one argument, which is an alist | ||
| 997 | specifying frame parameters. Any parameters not mentioned in the | ||
| 998 | argument alist default based on the value of @code{default-frame-alist}; | ||
| 999 | parameters not specified there default from the standard X defaults file | ||
| 1000 | and X resources. | ||
| 1001 | |||
| 1002 | When you invoke Emacs, if you specify arguments for window appearance | ||
| 1003 | and so forth, these go into @code{default-frame-alist} and that is how | ||
| 1004 | they have their effect. | ||
| 1005 | |||
| 1006 | You can specify the parameters for the initial startup X window frame by | ||
| 1007 | setting @code{initial-frame-alist} in your @file{.emacs} file. If these | ||
| 1008 | parameters specify a separate minibuffer-only frame, and you have not | ||
| 1009 | created one, Emacs creates one for you, using the parameter values | ||
| 1010 | specified in @code{minibuffer-frame-alist}. | ||
| 1011 | |||
| 1012 | You can specify the size and position of a frame using the frame | ||
| 1013 | parameters @code{left}, @code{top}, @code{height} and @code{width}. You | ||
| 1014 | must specify either both size parameters or neither. You must specify | ||
| 1015 | either both position parameters or neither. The geometry parameters | ||
| 1016 | that you don't specify are chosen by the window manager in its usual | ||
| 1017 | fashion. | ||
| 1018 | |||
| 1019 | The function @code{x-parse-geometry} converts a standard X windows | ||
| 1020 | geometry string to an alist which you can use as part of the argument to | ||
| 1021 | @code{make-frame}. | ||
| 1022 | |||
| 1023 | Use the function @code{delete-frame} to eliminate a frame. Frames are | ||
| 1024 | like buffers where deletion is concerned; a frame actually continues to | ||
| 1025 | exist as a Lisp object until it is deleted @emph{and} there are no | ||
| 1026 | references to it, but once it is deleted, it has no further effect on | ||
| 1027 | the screen. | ||
| 1028 | |||
| 1029 | The function @code{frame-live-p} returns non-@code{nil} if the argument | ||
| 1030 | (a frame) has not been deleted. | ||
| 1031 | |||
| 1032 | @subsection Finding All Frames | ||
| 1033 | |||
| 1034 | The function @code{frame-list} returns a list of all the frames that have | ||
| 1035 | not been deleted. It is analogous to @code{buffer-list}. The list that | ||
| 1036 | you get is newly created, so modifying the list doesn't have any effect | ||
| 1037 | on the internals of Emacs. The function @code{visible-frame-list} returns | ||
| 1038 | the list of just the frames that are visible. | ||
| 1039 | |||
| 1040 | @code{next-frame} lets you cycle conveniently through all the frames from an | ||
| 1041 | arbitrary starting point. Its first argument is a frame. Its second | ||
| 1042 | argument @var{minibuf} says what to do about minibuffers: | ||
| 1043 | |||
| 1044 | @table @asis | ||
| 1045 | @item @code{nil} | ||
| 1046 | Exclude minibuffer-only frames. | ||
| 1047 | @item a window | ||
| 1048 | Consider only the frames using that particular window as their | ||
| 1049 | minibuffer. | ||
| 1050 | @item anything else | ||
| 1051 | Consider all frames. | ||
| 1052 | @end table | ||
| 1053 | |||
| 1054 | @subsection Frames and Windows | ||
| 1055 | |||
| 1056 | All the non-minibuffer windows in a frame are arranged in a tree of | ||
| 1057 | subdivisions; the root of this tree is available via the function | ||
| 1058 | @code{frame-root-window}. Each window is part of one and only one | ||
| 1059 | frame; you can get the frame with @code{window-frame}. | ||
| 1060 | |||
| 1061 | At any time, exactly one window on any frame is @dfn{selected within the | ||
| 1062 | frame}. You can get the frame's current selected window with | ||
| 1063 | @code{frame-selected-window}. The significance of this designation is | ||
| 1064 | that selecting the frame selects for Emacs as a whole the window | ||
| 1065 | currently selected within that frame. | ||
| 1066 | |||
| 1067 | Conversely, selecting a window for Emacs with @code{select-window} also | ||
| 1068 | makes that window selected within its frame. | ||
| 1069 | |||
| 1070 | @subsection Frame Visibility | ||
| 1071 | |||
| 1072 | A frame may be @dfn{visible}, @dfn{invisible}, or @dfn{iconified}. If | ||
| 1073 | it is invisible, it doesn't show in the screen, not even as an icon. | ||
| 1074 | You can set the visibility status of a frame with | ||
| 1075 | @code{make-frame-visible}, @code{make-frame-invisible}, and | ||
| 1076 | @code{iconify-frame}. You can examine the visibility status with | ||
| 1077 | @code{frame-visible-p}---it returns @code{t} for a visible frame, | ||
| 1078 | @code{nil} for an invisible frame, and @code{icon} for an iconified | ||
| 1079 | frame. | ||
| 1080 | |||
| 1081 | @subsection Selected Frame | ||
| 1082 | |||
| 1083 | At any time, one frame in Emacs is the @dfn{selected frame}. The selected | ||
| 1084 | window always resides on the selected frame. | ||
| 1085 | |||
| 1086 | @defun selected-frame | ||
| 1087 | This function returns the selected frame. | ||
| 1088 | @end defun | ||
| 1089 | |||
| 1090 | The X server normally directs keyboard input to the X window that the | ||
| 1091 | mouse is in. Some window managers use mouse clicks or keyboard events | ||
| 1092 | to @dfn{shift the focus} to various X windows, overriding the normal | ||
| 1093 | behavior of the server. | ||
| 1094 | |||
| 1095 | Lisp programs can switch frames ``temporarily'' by calling the function | ||
| 1096 | @code{select-frame}. This does not override the window manager; rather, | ||
| 1097 | it escapes from the window manager's control until that control is | ||
| 1098 | somehow reasserted. The function takes one argument, a frame, and | ||
| 1099 | selects that frame. The selection lasts until the next time the user | ||
| 1100 | does something to select a different frame, or until the next time this | ||
| 1101 | function is called. | ||
| 1102 | |||
| 1103 | Emacs cooperates with the X server and the window managers by arranging | ||
| 1104 | to select frames according to what the server and window manager ask | ||
| 1105 | for. It does so by generating a special kind of input event, called a | ||
| 1106 | @dfn{focus} event. The command loop handles a focus event by calling | ||
| 1107 | @code{internal-select-frame}. @xref{Focus Events}. | ||
| 1108 | |||
| 1109 | @subsection Frame Size and Position | ||
| 1110 | |||
| 1111 | The new functions @code{frame-height} and @code{frame-width} return the | ||
| 1112 | height and width of a specified frame (or of the selected frame), | ||
| 1113 | measured in characters. | ||
| 1114 | |||
| 1115 | The new functions @code{frame-pixel-height} and @code{frame-pixel-width} | ||
| 1116 | return the height and width of a specified frame (or of the selected | ||
| 1117 | frame), measured in pixels. | ||
| 1118 | |||
| 1119 | The new functions @code{frame-char-height} and @code{frame-char-width} | ||
| 1120 | return the height and width of a character in a specified frame (or in | ||
| 1121 | the selected frame), measured in pixels. | ||
| 1122 | |||
| 1123 | @code{set-frame-size} sets the size of a frame, measured in characters; | ||
| 1124 | its arguments are @var{frame}, @var{cols} and @var{rows}. To set the | ||
| 1125 | size with values measured in pixels, you can use | ||
| 1126 | @code{modify-frame-parameters}. | ||
| 1127 | |||
| 1128 | The function @code{set-frame-position} sets the position of the top left | ||
| 1129 | corner of a frame. Its arguments are @var{frame}, @var{left} and | ||
| 1130 | @var{top}. | ||
| 1131 | |||
| 1132 | @ignore | ||
| 1133 | New functions @code{set-frame-height} and @code{set-frame-width} set the | ||
| 1134 | size of a specified frame. The frame is the first argument; the size is | ||
| 1135 | the second. | ||
| 1136 | @end ignore | ||
| 1137 | |||
| 1138 | @subsection Frame Parameters | ||
| 1139 | |||
| 1140 | A frame has many parameters that affect how it displays. Use the | ||
| 1141 | function @code{frame-parameters} to get an alist of all the parameters | ||
| 1142 | of a given frame. To alter parameters, use | ||
| 1143 | @code{modify-frame-parameters}, which takes two arguments: the frame to | ||
| 1144 | modify, and an alist of parameters to change and their new values. Each | ||
| 1145 | element of @var{alist} has the form @code{(@var{parm} . @var{value})}, | ||
| 1146 | where @var{parm} is a symbol. Parameters that aren't meaningful are | ||
| 1147 | ignored. If you don't mention a parameter in @var{alist}, its value | ||
| 1148 | doesn't change. | ||
| 1149 | |||
| 1150 | Just what parameters a frame has depends on what display mechanism it | ||
| 1151 | uses. Here is a table of the parameters of an X | ||
| 1152 | window frame: | ||
| 1153 | |||
| 1154 | @table @code | ||
| 1155 | @item name | ||
| 1156 | The name of the frame. | ||
| 1157 | |||
| 1158 | @item left | ||
| 1159 | The screen position of the left edge. | ||
| 1160 | |||
| 1161 | @item top | ||
| 1162 | The screen position of the top edge. | ||
| 1163 | |||
| 1164 | @item height | ||
| 1165 | The height of the frame contents, in pixels. | ||
| 1166 | |||
| 1167 | @item width | ||
| 1168 | The width of the frame contents, in pixels. | ||
| 1169 | |||
| 1170 | @item window-id | ||
| 1171 | The number of the X window for the frame. | ||
| 1172 | |||
| 1173 | @item minibuffer | ||
| 1174 | Whether this frame has its own minibuffer. | ||
| 1175 | @code{t} means yes, @code{none} means no, | ||
| 1176 | @code{only} means this frame is just a minibuffer, | ||
| 1177 | a minibuffer window (in some other frame) | ||
| 1178 | means the new frame uses that minibuffer. | ||
| 1179 | |||
| 1180 | @item font | ||
| 1181 | The name of the font for the text. | ||
| 1182 | |||
| 1183 | @item foreground-color | ||
| 1184 | The color to use for the inside of a character. | ||
| 1185 | Use strings to designate colors; | ||
| 1186 | X windows defines the meaningful color names. | ||
| 1187 | |||
| 1188 | @item background-color | ||
| 1189 | The color to use for the background of text. | ||
| 1190 | |||
| 1191 | @item mouse-color | ||
| 1192 | The color for the mouse cursor. | ||
| 1193 | |||
| 1194 | @item cursor-color | ||
| 1195 | The color for the cursor that shows point. | ||
| 1196 | |||
| 1197 | @item border-color | ||
| 1198 | The color for the border of the frame. | ||
| 1199 | |||
| 1200 | @item cursor-type | ||
| 1201 | The way to display the cursor. There are two legitimate values: | ||
| 1202 | @code{bar} and @code{box}. The value @code{bar} specifies a vertical | ||
| 1203 | bar between characters as the cursor. The value @code{box} specifies an | ||
| 1204 | ordinary black box overlaying the character after point; that is the | ||
| 1205 | default. | ||
| 1206 | |||
| 1207 | @item icon-type | ||
| 1208 | Non-@code{nil} for a bitmap icon, @code{nil} for a text icon. | ||
| 1209 | |||
| 1210 | @item border-width | ||
| 1211 | The width in pixels of the window border. | ||
| 1212 | |||
| 1213 | @item internal-border-width | ||
| 1214 | The distance in pixels between text and border. | ||
| 1215 | |||
| 1216 | @item auto-raise | ||
| 1217 | Non-@code{nil} means selecting the frame raises it. | ||
| 1218 | |||
| 1219 | @item auto-lower | ||
| 1220 | Non-@code{nil} means deselecting the frame lowers it. | ||
| 1221 | |||
| 1222 | @item vertical-scrollbar | ||
| 1223 | Non-@code{nil} gives the frame a scroll bar | ||
| 1224 | for vertical scrolling. | ||
| 1225 | |||
| 1226 | @item horizontal-scrollbar | ||
| 1227 | Non-@code{nil} gives the frame a scroll bar | ||
| 1228 | for horizontal scrolling. | ||
| 1229 | @end table | ||
| 1230 | |||
| 1231 | @subsection Minibufferless Frames | ||
| 1232 | |||
| 1233 | Normally, each frame has its own minibuffer window at the bottom, which | ||
| 1234 | is used whenever that frame is selected. However, you can also create | ||
| 1235 | frames with no minibuffers. These frames must use the minibuffer window | ||
| 1236 | of some other frame. | ||
| 1237 | |||
| 1238 | The variable @code{default-minibuffer-frame} specifies where to find a | ||
| 1239 | minibuffer for frames created without minibuffers of their own. Its | ||
| 1240 | value should be a frame which does have a minibuffer. | ||
| 1241 | |||
| 1242 | You can also specify a minibuffer window explicitly when you create a | ||
| 1243 | frame; then @code{default-minibuffer-frame} is not used. | ||
| 1244 | |||
| 1245 | @section X Windows Features | ||
| 1246 | |||
| 1247 | @itemize @bullet | ||
| 1248 | @item | ||
| 1249 | The new functions @code{mouse-position} and @code{set-mouse-position} give | ||
| 1250 | access to the current position of the mouse. | ||
| 1251 | |||
| 1252 | @code{mouse-position} returns a description of the position of the mouse. | ||
| 1253 | The value looks like @code{(@var{frame} @var{x} . @var{y})}, where @var{x} | ||
| 1254 | and @var{y} are measured in pixels relative to the top left corner of | ||
| 1255 | the inside of @var{frame}. | ||
| 1256 | |||
| 1257 | @code{set-mouse-position} takes three arguments, @var{frame}, @var{x} | ||
| 1258 | and @var{y}, and warps the mouse cursor to that location on the screen. | ||
| 1259 | |||
| 1260 | @item | ||
| 1261 | @code{track-mouse} is a new special form for tracking mouse motion. | ||
| 1262 | Use it in definitions of mouse clicks that want pay to attention to | ||
| 1263 | the motion of the mouse, not just where the buttons are pressed and | ||
| 1264 | released. Here is how to use it: | ||
| 1265 | |||
| 1266 | @example | ||
| 1267 | (track-mouse @var{body}@dots{}) | ||
| 1268 | @end example | ||
| 1269 | |||
| 1270 | While @var{body} executes, mouse motion generates input events just as mouse | ||
| 1271 | clicks do. @var{body} can read them with @code{read-event} or | ||
| 1272 | @code{read-key-sequence}. | ||
| 1273 | |||
| 1274 | @code{track-mouse} returns the value of the last form in @var{body}. | ||
| 1275 | |||
| 1276 | The format of these events is described under ``New features for key | ||
| 1277 | bindings and input.'' | ||
| 1278 | @c ??? | ||
| 1279 | |||
| 1280 | @item | ||
| 1281 | @code{x-set-selection} sets a ``selection'' in the X Windows server. | ||
| 1282 | It takes two arguments: a selection type @var{type}, and the value to | ||
| 1283 | assign to it, @var{data}. If @var{data} is @code{nil}, it means to | ||
| 1284 | clear out the selection. Otherwise, @var{data} may be a string, a | ||
| 1285 | symbol, an integer (or a cons of two integers or list of two integers), | ||
| 1286 | or a cons of two markers pointing to the same buffer. In the last case, | ||
| 1287 | the selection is considered to be the text between the markers. The | ||
| 1288 | data may also be a vector of valid non-vector selection values. | ||
| 1289 | |||
| 1290 | Each possible @var{type} has its own selection value, which changes | ||
| 1291 | independently. The usual values of @var{type} are @code{PRIMARY} and | ||
| 1292 | @code{SECONDARY}; these are symbols with upper-case names, in accord | ||
| 1293 | with X Windows conventions. The default is @code{PRIMARY}. | ||
| 1294 | |||
| 1295 | To get the value of the selection, call @code{x-get-selection}. This | ||
| 1296 | function accesses selections set up by Emacs and those set up by other X | ||
| 1297 | clients. It takes two optional arguments, @var{type} and | ||
| 1298 | @var{data-type}. The default for @var{type} is @code{PRIMARY}. | ||
| 1299 | |||
| 1300 | The @var{data-type} argument specifies the form of data conversion to | ||
| 1301 | use; meaningful values include @code{TEXT}, @code{STRING}, | ||
| 1302 | @code{TARGETS}, @code{LENGTH}, @code{DELETE}, @code{FILE_NAME}, | ||
| 1303 | @code{CHARACTER_POSITION}, @code{LINE_NUMBER}, @code{COLUMN_NUMBER}, | ||
| 1304 | @code{OWNER_OS}, @code{HOST_NAME}, @code{USER}, @code{CLASS}, | ||
| 1305 | @code{NAME}, @code{ATOM}, and @code{INTEGER}. (These are symbols with | ||
| 1306 | upper-case names in accord with X Windows conventions.) | ||
| 1307 | The default for @var{data-type} is @code{STRING}. | ||
| 1308 | |||
| 1309 | @item | ||
| 1310 | X Windows has a set of numbered @dfn{cut buffers} which can store text | ||
| 1311 | or other data being moved between applications. Use | ||
| 1312 | @code{x-get-cut-buffer} to get the contents of a cut buffer; specify the | ||
| 1313 | cut buffer number as argument. Use @code{x-set-cut-buffer} with | ||
| 1314 | argument @var{string} to store a new string into the first cut buffer | ||
| 1315 | (moving the other values down through the series of cut buffers, | ||
| 1316 | kill-ring-style). | ||
| 1317 | |||
| 1318 | Cut buffers are considered obsolete in X Windows, but Emacs supports | ||
| 1319 | them for the sake of X clients that still use them. | ||
| 1320 | |||
| 1321 | @item | ||
| 1322 | You can close the connection with the X Windows server with | ||
| 1323 | the function @code{x-close-current-connection}. This takes no arguments. | ||
| 1324 | |||
| 1325 | Then you can connect to a different X Windows server with | ||
| 1326 | @code{x-open-connection}. The first argument, @var{display}, is the | ||
| 1327 | name of the display to connect to. | ||
| 1328 | |||
| 1329 | The optional second argument @var{xrm-string} is a string of resource | ||
| 1330 | names and values, in the same format used in the @file{.Xresources} | ||
| 1331 | file. The values you specify override the resource values recorded in | ||
| 1332 | the X Windows server itself. Here's an example of what this string | ||
| 1333 | might look like: | ||
| 1334 | |||
| 1335 | @example | ||
| 1336 | "*BorderWidth: 3\n*InternalBorder: 2\n" | ||
| 1337 | @end example | ||
| 1338 | |||
| 1339 | @item | ||
| 1340 | A series of new functions give you information about the X server and | ||
| 1341 | the screen you are using. | ||
| 1342 | |||
| 1343 | @table @code | ||
| 1344 | @item x-display-screens | ||
| 1345 | The number of screens associated with the current display. | ||
| 1346 | |||
| 1347 | @item x-server-version | ||
| 1348 | The version numbers of the X server in use. | ||
| 1349 | |||
| 1350 | @item x-server-vendor | ||
| 1351 | The vendor supporting the X server in use. | ||
| 1352 | |||
| 1353 | @item x-display-pixel-height | ||
| 1354 | The height of this X screen in pixels. | ||
| 1355 | |||
| 1356 | @item x-display-mm-height | ||
| 1357 | The height of this X screen in millimeters. | ||
| 1358 | |||
| 1359 | @item x-display-pixel-width | ||
| 1360 | The width of this X screen in pixels. | ||
| 1361 | |||
| 1362 | @item x-display-mm-width | ||
| 1363 | The width of this X screen in millimeters. | ||
| 1364 | |||
| 1365 | @item x-display-backing-store | ||
| 1366 | The backing store capability of this screen. Values can be the symbols | ||
| 1367 | @code{always}, @code{when-mapped}, or @code{not-useful}. | ||
| 1368 | |||
| 1369 | @item x-display-save-under | ||
| 1370 | Non-@code{nil} if this X screen supports the SaveUnder feature. | ||
| 1371 | |||
| 1372 | @item x-display-planes | ||
| 1373 | The number of planes this display supports. | ||
| 1374 | |||
| 1375 | @item x-display-visual-class | ||
| 1376 | The visual class for this X screen. The value is one of the symbols | ||
| 1377 | @code{static-gray}, @code{gray-scale}, @code{static-color}, | ||
| 1378 | @code{pseudo-color}, @code{true-color}, and @code{direct-color}. | ||
| 1379 | |||
| 1380 | @item x-display-color-p | ||
| 1381 | @code{t} if the X screen in use is a color screen. | ||
| 1382 | |||
| 1383 | @item x-display-color-cells | ||
| 1384 | The number of color cells this X screen supports. | ||
| 1385 | @end table | ||
| 1386 | |||
| 1387 | There is also a variable @code{x-no-window-manager}, whose value is | ||
| 1388 | @code{t} if no X window manager is in use. | ||
| 1389 | |||
| 1390 | @item | ||
| 1391 | The function @code{x-synchronize} enables or disables an X Windows | ||
| 1392 | debugging mode: synchronous communication. It takes one argument, | ||
| 1393 | non-@code{nil} to enable the mode and @code{nil} to disable. | ||
| 1394 | |||
| 1395 | In synchronous mode, Emacs waits for a response to each X protocol | ||
| 1396 | command before doing anything else. This means that errors are reported | ||
| 1397 | right away, and you can directly find the erroneous command. | ||
| 1398 | Synchronous mode is not the default because it is much slower. | ||
| 1399 | |||
| 1400 | @item | ||
| 1401 | The function @code{x-get-resource} retrieves a resource value from the X | ||
| 1402 | Windows defaults database. Its three arguments are @var{attribute}, | ||
| 1403 | @var{name} and @var{class}. It searches using a key of the form | ||
| 1404 | @samp{@var{instance}.@var{attribute}}, with class @samp{Emacs}, where | ||
| 1405 | @var{instance} is the name under which Emacs was invoked. | ||
| 1406 | |||
| 1407 | The optional arguments @var{component} and @var{subclass} add to the key | ||
| 1408 | and the class, respectively. You must specify both of them or neither. | ||
| 1409 | If you specify them, the key is | ||
| 1410 | @samp{@var{instance}.@var{component}.@var{attribute}}, and the class is | ||
| 1411 | @samp{Emacs.@var{subclass}}. | ||
| 1412 | |||
| 1413 | @item | ||
| 1414 | @code{x-color-display-p} returns @code{t} if you are using an X Window | ||
| 1415 | server with a color display, and @code{nil} otherwise. | ||
| 1416 | |||
| 1417 | @c ??? Name being changed from x-defined-color. | ||
| 1418 | @code{x-color-defined-p} takes as argument a string describing a color; it | ||
| 1419 | returns @code{t} if the display supports that color. (If the color is | ||
| 1420 | @code{"black"} or @code{"white"} then even black-and-white displays | ||
| 1421 | support it.) | ||
| 1422 | |||
| 1423 | @item | ||
| 1424 | @code{x-popup-menu} has been generalized. It now accepts a keymap as | ||
| 1425 | the @var{menu} argument. Then the menu items are the prompt strings of | ||
| 1426 | individual key bindings, and the item values are the keys which have | ||
| 1427 | those bindings. | ||
| 1428 | |||
| 1429 | You can also supply a list of keymaps as the first argument; then each | ||
| 1430 | keymap makes one menu pane (but keymaps that don't provide any menu | ||
| 1431 | items don't appear in the menu at all). | ||
| 1432 | |||
| 1433 | @code{x-popup-menu} also accepts a mouse button event as the | ||
| 1434 | @var{position} argument. Then it displays the menu at the location at | ||
| 1435 | which the event took place. This is convenient for mouse-invoked | ||
| 1436 | commands that pop up menus. | ||
| 1437 | |||
| 1438 | @ignore | ||
| 1439 | @item | ||
| 1440 | x-pointer-shape, x-nontext-pointer-shape, x-mode-pointer-shape. | ||
| 1441 | @end ignore | ||
| 1442 | |||
| 1443 | @item | ||
| 1444 | You can use the function @code{x-rebind-key} to change the sequence | ||
| 1445 | of characters generated by one of the keyboard keys. This works | ||
| 1446 | only with X Windows. | ||
| 1447 | |||
| 1448 | The first two arguments, @var{keycode} and @var{shift-mask}, should be | ||
| 1449 | numbers representing the keyboard code and shift mask respectively. | ||
| 1450 | They specify what key to change. | ||
| 1451 | |||
| 1452 | The third argument, @var{newstring}, is the new definition of the key. | ||
| 1453 | It is a sequence of characters that the key should produce as input. | ||
| 1454 | |||
| 1455 | The shift mask value is a combination of bits according to this table: | ||
| 1456 | |||
| 1457 | @table @asis | ||
| 1458 | @item 8 | ||
| 1459 | Control | ||
| 1460 | @item 4 | ||
| 1461 | Meta | ||
| 1462 | @item 2 | ||
| 1463 | Shift | ||
| 1464 | @item 1 | ||
| 1465 | Shift Lock | ||
| 1466 | @end table | ||
| 1467 | |||
| 1468 | If you specify @code{nil} for @var{shift-mask}, then the key specified | ||
| 1469 | by @var{keycode} is redefined for all possible shift combinations. | ||
| 1470 | |||
| 1471 | For the possible values of @var{keycode} and their meanings, see the | ||
| 1472 | file @file{/usr/lib/Xkeymap.txt}. Keep in mind that the codes in that | ||
| 1473 | file are in octal! | ||
| 1474 | |||
| 1475 | @ignore @c Presumably this is already fixed | ||
| 1476 | NOTE: due to an X bug, this function will not take effect unless the | ||
| 1477 | user has a @file{~/.Xkeymap} file. (See the documentation for the | ||
| 1478 | @code{keycomp} program.) This problem will be fixed in X version 11. | ||
| 1479 | @end ignore | ||
| 1480 | |||
| 1481 | The related function @code{x-rebind-keys} redefines a single keyboard | ||
| 1482 | key, specifying the behavior for each of the 16 shift masks | ||
| 1483 | independently. The first argument is @var{keycode}, as in | ||
| 1484 | @code{x-rebind-key}. The second argument @var{strings} is a list of 16 | ||
| 1485 | elements, one for each possible shift mask value; each element says how | ||
| 1486 | to redefine the key @var{keycode} with the corresponding shift mask | ||
| 1487 | value. If an element is a string, it is the new definition. If an | ||
| 1488 | element is @code{nil}, the definition does not change for that shift | ||
| 1489 | mask. | ||
| 1490 | |||
| 1491 | @item | ||
| 1492 | The function @code{x-geometry} parses a string specifying window size | ||
| 1493 | and position in the usual fashion for X windows. It returns an alist | ||
| 1494 | describing which parameters were specified, and the values that were | ||
| 1495 | given for them. | ||
| 1496 | |||
| 1497 | The elements of the alist look like @code{(@var{parameter} . | ||
| 1498 | @var{value})}. The possible @var{parameter} values are @code{left}, | ||
| 1499 | @code{top}, @code{width}, and @code{height}. | ||
| 1500 | @end itemize | ||
| 1501 | |||
| 1502 | @section New Window Features | ||
| 1503 | |||
| 1504 | @itemize @bullet | ||
| 1505 | @item | ||
| 1506 | The new function @code{window-at} tells you which window contains a | ||
| 1507 | given horizontal and vertical position on a specified frame. Call it | ||
| 1508 | with three arguments, like this: | ||
| 1509 | |||
| 1510 | @example | ||
| 1511 | (window-at @var{x} @var{column} @var{frame}) | ||
| 1512 | @end example | ||
| 1513 | |||
| 1514 | The function returns the window which contains that cursor position in | ||
| 1515 | the frame @var{frame}. If you omit @var{frame}, the selected frame is | ||
| 1516 | used. | ||
| 1517 | |||
| 1518 | @item | ||
| 1519 | The function @code{coordinates-in-window-p} takes two arguments and | ||
| 1520 | checks whether a particular frame position falls within a particular | ||
| 1521 | window. | ||
| 1522 | |||
| 1523 | @example | ||
| 1524 | (coordinates-in-window-p @var{coordinates} @var{window}) | ||
| 1525 | @end example | ||
| 1526 | |||
| 1527 | The argument @var{coordinates} is a cons cell of this form: | ||
| 1528 | |||
| 1529 | @example | ||
| 1530 | (@var{x} . @var{y}) | ||
| 1531 | @end example | ||
| 1532 | |||
| 1533 | @noindent | ||
| 1534 | The two coordinates are measured in characters, and count from the top | ||
| 1535 | left corner of the screen or frame. | ||
| 1536 | |||
| 1537 | The value of the function tells you what part of the window the position | ||
| 1538 | is in. The possible values are: | ||
| 1539 | |||
| 1540 | @table @code | ||
| 1541 | @item (@var{relx} . @var{rely}) | ||
| 1542 | The coordinates are inside @var{window}. The numbers @var{relx} and | ||
| 1543 | @var{rely} are equivalent window-relative coordinates, counting from 0 | ||
| 1544 | at the top left corner of the window. | ||
| 1545 | |||
| 1546 | @item mode-line | ||
| 1547 | The coordinates are in the mode line of @var{window}. | ||
| 1548 | |||
| 1549 | @item vertical-split | ||
| 1550 | The coordinates are in the vertical line between @var{window} and its | ||
| 1551 | neighbor to the right. | ||
| 1552 | |||
| 1553 | @item nil | ||
| 1554 | The coordinates are not in any sense within @var{window}. | ||
| 1555 | @end table | ||
| 1556 | |||
| 1557 | You need not specify a frame when you call | ||
| 1558 | @code{coordinates-in-window-p}, because it assumes you mean the frame | ||
| 1559 | which window @var{window} is on. | ||
| 1560 | |||
| 1561 | @item | ||
| 1562 | The function @code{minibuffer-window} now accepts a frame as argument | ||
| 1563 | and returns the minibuffer window used for that frame. If you don't | ||
| 1564 | specify a frame, the currently selected frame is used. The minibuffer | ||
| 1565 | window may be on the frame in question, but if that frame has no | ||
| 1566 | minibuffer of its own, it uses the minibuffer window of some other | ||
| 1567 | frame, and @code{minibuffer-window} returns that window. | ||
| 1568 | |||
| 1569 | @item | ||
| 1570 | Use @code{window-live-p} to test whether a window is still alive (that | ||
| 1571 | is, not deleted). | ||
| 1572 | |||
| 1573 | @item | ||
| 1574 | Use @code{window-minibuffer-p} to determine whether a given window is a | ||
| 1575 | minibuffer or not. It no longer works to do this by comparing the | ||
| 1576 | window with the result of @code{(minibuffer-window)}, because there can | ||
| 1577 | be more than one minibuffer window at a time (if you have multiple | ||
| 1578 | frames). | ||
| 1579 | |||
| 1580 | @item | ||
| 1581 | If you set the variable @code{pop-up-frames} non-@code{nil}, then the | ||
| 1582 | functions to show something ``in another window'' actually create a new | ||
| 1583 | frame for the new window. Thus, you will tend to have a frame for each | ||
| 1584 | window, and you can easily have a frame for each buffer. | ||
| 1585 | |||
| 1586 | The value of the variable @code{pop-up-frame-function} controls how new | ||
| 1587 | frames are made. The value should be a function which takes no | ||
| 1588 | arguments and returns a frame. The default value is a function which | ||
| 1589 | creates a frame using parameters from @code{pop-up-frame-alist}. | ||
| 1590 | |||
| 1591 | @item | ||
| 1592 | @code{display-buffer} is the basic primitive for finding a way to show a | ||
| 1593 | buffer on the screen. You can customize its behavior by storing a | ||
| 1594 | function in the variable @code{display-buffer-function}. If this | ||
| 1595 | variable is non-@code{nil}, then @code{display-buffer} calls it to do | ||
| 1596 | the work. Your function should accept two arguments, as follows: | ||
| 1597 | |||
| 1598 | @table @var | ||
| 1599 | @item buffer | ||
| 1600 | The buffer to be displayed. | ||
| 1601 | |||
| 1602 | @item flag | ||
| 1603 | A flag which, if non-@code{nil}, means you should find another window to | ||
| 1604 | display @var{buffer} in, even if it is already visible in the selected | ||
| 1605 | window. | ||
| 1606 | @end table | ||
| 1607 | |||
| 1608 | The function you supply will be used by commands such as | ||
| 1609 | @code{switch-to-buffer-other-window} and @code{find-file-other-window} | ||
| 1610 | as well as for your own calls to @code{display-buffer}. | ||
| 1611 | |||
| 1612 | @item | ||
| 1613 | @code{delete-window} now gives all of the deleted window's screen space | ||
| 1614 | to a single neighboring window. Likewise, @code{enlarge-window} takes | ||
| 1615 | space from only one neighboring window until that window disappears; | ||
| 1616 | only then does it take from another window. | ||
| 1617 | |||
| 1618 | @item | ||
| 1619 | @code{next-window} and @code{previous-window} accept another argument, | ||
| 1620 | @var{all-frames}. | ||
| 1621 | |||
| 1622 | These functions now take three optional arguments: @var{window}, | ||
| 1623 | @var{minibuf} and @var{all-frames}. @var{window} is the window to start | ||
| 1624 | from (@code{nil} means use the selected window). @var{minibuf} says | ||
| 1625 | whether to include the minibuffer in the windows to cycle through: | ||
| 1626 | @code{t} means yes, @code{nil} means yes if it is active, and anything | ||
| 1627 | else means no. | ||
| 1628 | |||
| 1629 | Normally, these functions cycle through all the windows in the | ||
| 1630 | selected frame, plus the minibuffer used by the selected frame even if | ||
| 1631 | it lies in some other frame. | ||
| 1632 | |||
| 1633 | If @var{all-frames} is @code{t}, then these functions cycle through | ||
| 1634 | all the windows in all the frames that currently exist. If | ||
| 1635 | @var{all-frames} is neither @code{t} nor @code{nil}, then they limit | ||
| 1636 | themselves strictly to the windows in the selected frame, excluding the | ||
| 1637 | minibuffer in use if it lies in some other frame. | ||
| 1638 | |||
| 1639 | @item | ||
| 1640 | The functions @code{get-lru-window} and @code{get-largest-window} now | ||
| 1641 | take an optional argument @var{all-frames}. If it is non-@code{nil}, | ||
| 1642 | the functions consider all windows on all frames. Otherwise, they | ||
| 1643 | consider just the windows on the selected frame. | ||
| 1644 | |||
| 1645 | Likewise, @code{get-buffer-window} takes an optional second argument | ||
| 1646 | @var{all-frames}. | ||
| 1647 | |||
| 1648 | @item | ||
| 1649 | The variable @code{other-window-scroll-buffer} specifies which buffer | ||
| 1650 | @code{scroll-other-window} should scroll. | ||
| 1651 | |||
| 1652 | @item | ||
| 1653 | You can now mark a window as ``dedicated'' to its buffer. | ||
| 1654 | Then Emacs will not try to use that window for any other buffer | ||
| 1655 | unless you explicitly request it. | ||
| 1656 | |||
| 1657 | Use the new function @code{set-window-dedicated-p} to set the dedication | ||
| 1658 | flag of a window @var{window} to the value @var{flag}. If @var{flag} is | ||
| 1659 | @code{t}, this makes the window dedicated. If @var{flag} is | ||
| 1660 | @code{nil}, this makes the window non-dedicated. | ||
| 1661 | |||
| 1662 | Use @code{window-dedicated-p} to examine the dedication flag of a | ||
| 1663 | specified window. | ||
| 1664 | |||
| 1665 | @item | ||
| 1666 | The new function @code{walk-windows} cycles through all visible | ||
| 1667 | windows, calling @code{proc} once for each window with the window as | ||
| 1668 | its sole argument. | ||
| 1669 | |||
| 1670 | The optional second argument @var{minibuf} says whether to include minibuffer | ||
| 1671 | windows. A value of @code{t} means count the minibuffer window even if | ||
| 1672 | not active. A value of @code{nil} means count it only if active. Any | ||
| 1673 | other value means not to count the minibuffer even if it is active. | ||
| 1674 | |||
| 1675 | If the optional third argument @var{all-frames} is @code{t}, that means | ||
| 1676 | include all windows in all frames. If @var{all-frames} is @code{nil}, | ||
| 1677 | it means to cycle within the selected frame, but include the minibuffer | ||
| 1678 | window (if @var{minibuf} says so) that that frame uses, even if it is on | ||
| 1679 | another frame. If @var{all-frames} is neither @code{nil} nor @code{t}, | ||
| 1680 | @code{walk-windows} sticks strictly to the selected frame. | ||
| 1681 | |||
| 1682 | @item | ||
| 1683 | The function @code{window-end} is a counterpart to @code{window-start}: | ||
| 1684 | it returns the buffer position of the end of the display in a given | ||
| 1685 | window (or the selected window). | ||
| 1686 | |||
| 1687 | @item | ||
| 1688 | The function @code{window-configuration-p} returns non-@code{nil} when | ||
| 1689 | given an object that is a window configuration (such as is returned by | ||
| 1690 | @code{current-window-configuration}). | ||
| 1691 | @end itemize | ||
| 1692 | |||
| 1693 | @section Display Features | ||
| 1694 | |||
| 1695 | @itemize @bullet | ||
| 1696 | @item | ||
| 1697 | @samp{%l} as a mode line item displays the current line number. | ||
| 1698 | |||
| 1699 | If the buffer is longer than @code{line-number-display-limit} | ||
| 1700 | characters, or if lines are too long in the viscinity of the current | ||
| 1701 | displayed text, then line number display is inhibited to save time. | ||
| 1702 | |||
| 1703 | The default contents of the mode line include the line number if | ||
| 1704 | @code{line-number-mode} is non-@code{nil}. | ||
| 1705 | |||
| 1706 | @item | ||
| 1707 | @code{baud-rate} is now a variable rather than a function. This is so | ||
| 1708 | you can set it to reflect the effective speed of your terminal, when the | ||
| 1709 | system doesn't accurately know the speed. | ||
| 1710 | |||
| 1711 | @item | ||
| 1712 | You can now remove any echo area message and make the minibuffer | ||
| 1713 | visible. To do this, call @code{message} with @code{nil} as the only | ||
| 1714 | argument. This clears any existing message, and lets the current | ||
| 1715 | minibuffer contents show through. Previously, there was no reliable way | ||
| 1716 | to make sure that the minibuffer contents were visible. | ||
| 1717 | |||
| 1718 | @item | ||
| 1719 | The variable @code{temp-buffer-show-hook} has been renamed | ||
| 1720 | @code{temp-buffer-show-function}, because its value is a single function | ||
| 1721 | (of one argument), not a normal hook. | ||
| 1722 | |||
| 1723 | @item | ||
| 1724 | The new function @code{force-mode-line-update} causes redisplay | ||
| 1725 | of the current buffer's mode line. | ||
| 1726 | @end itemize | ||
| 1727 | |||
| 1728 | @section Display Tables | ||
| 1729 | |||
| 1730 | @cindex display table | ||
| 1731 | You can use the @dfn{display table} feature to control how all 256 | ||
| 1732 | possible character codes display on the screen. This is useful for | ||
| 1733 | displaying European languages that have letters not in the ASCII | ||
| 1734 | character set. | ||
| 1735 | |||
| 1736 | The display table maps each character code into a sequence of | ||
| 1737 | @dfn{glyphs}, each glyph being an image that takes up one character | ||
| 1738 | position on the screen. You can also define how to display each glyph | ||
| 1739 | on your terminal, using the @dfn{glyph table}. | ||
| 1740 | |||
| 1741 | @subsection Display Tables | ||
| 1742 | |||
| 1743 | Use @code{make-display-table} to create a display table. The table | ||
| 1744 | initially has @code{nil} in all elements. | ||
| 1745 | |||
| 1746 | A display table is actually an array of 261 elements. The first 256 | ||
| 1747 | elements of a display table control how to display each possible text | ||
| 1748 | character. The value should be @code{nil} or a vector (which is a | ||
| 1749 | sequence of glyphs; see below). @code{nil} as an element means to | ||
| 1750 | display that character following the usual display conventions. | ||
| 1751 | |||
| 1752 | The remaining five elements of a display table serve special purposes | ||
| 1753 | (@code{nil} means use the default stated below): | ||
| 1754 | |||
| 1755 | @table @asis | ||
| 1756 | @item 256 | ||
| 1757 | The glyph for the end of a truncated screen line (the default for this | ||
| 1758 | is @samp{\}). | ||
| 1759 | @item 257 | ||
| 1760 | The glyph for the end of a continued line (the default is @samp{$}). | ||
| 1761 | @item 258 | ||
| 1762 | The glyph for the indicating an octal character code (the default is | ||
| 1763 | @samp{\}). | ||
| 1764 | @item 259 | ||
| 1765 | The glyph for indicating a control characters (the default is @samp{^}). | ||
| 1766 | @item 260 | ||
| 1767 | The vector of glyphs for indicating the presence of invisible lines (the | ||
| 1768 | default is @samp{...}). | ||
| 1769 | @end table | ||
| 1770 | |||
| 1771 | Each buffer typically has its own display table. The display table for | ||
| 1772 | the current buffer is stored in @code{buffer-display-table}. (This | ||
| 1773 | variable automatically becomes local if you set it.) If this variable | ||
| 1774 | is @code{nil}, the value of @code{standard-display-table} is used in | ||
| 1775 | that buffer. | ||
| 1776 | |||
| 1777 | Each window can have its own display table, which overrides the display | ||
| 1778 | table of the buffer it is showing. | ||
| 1779 | |||
| 1780 | If neither the selected window nor the current buffer has a display | ||
| 1781 | table, and if @code{standard-display-table} is @code{nil}, then Emacs | ||
| 1782 | uses the usual display conventions: | ||
| 1783 | |||
| 1784 | @itemize @bullet | ||
| 1785 | @item | ||
| 1786 | Character codes 32 through 127 map to glyph codes 32 through 127. | ||
| 1787 | @item | ||
| 1788 | Codes 0 through 31 map to sequences of two glyphs, where the first glyph | ||
| 1789 | is the ASCII code for @samp{^}. | ||
| 1790 | @item | ||
| 1791 | Character codes 128 through 255 map to sequences of four glyphs, where | ||
| 1792 | the first glyph is the ASCII code for @samp{\}, and the others represent | ||
| 1793 | digits. | ||
| 1794 | @end itemize | ||
| 1795 | |||
| 1796 | The usual display conventions are also used for any character whose | ||
| 1797 | entry in the active display table is @code{nil}. This means that when | ||
| 1798 | you set up a display table, you need not specify explicitly what to do | ||
| 1799 | with each character, only the characters for which you want unusual | ||
| 1800 | behavior. | ||
| 1801 | |||
| 1802 | @subsection Glyphs | ||
| 1803 | |||
| 1804 | @cindex glyph | ||
| 1805 | A glyph stands for an image that takes up a single character position on | ||
| 1806 | the screen. A glyph is represented in Lisp as an integer. | ||
| 1807 | |||
| 1808 | @cindex glyph table | ||
| 1809 | The meaning of each integer, as a glyph, is defined by the glyph table, | ||
| 1810 | which is the value of the variable @code{glyph-table}. It should be a | ||
| 1811 | vector; the @var{g}th element defines glyph code @var{g}. The possible | ||
| 1812 | definitions of a glyph code are: | ||
| 1813 | |||
| 1814 | @table @var | ||
| 1815 | @item integer | ||
| 1816 | Define this glyph code as an alias for code @var{integer}. | ||
| 1817 | This is used with X windows to specify a face code. | ||
| 1818 | |||
| 1819 | @item string | ||
| 1820 | Send the characters in @var{string} to the terminal to output | ||
| 1821 | this glyph. This alternative is not available with X Windows. | ||
| 1822 | |||
| 1823 | @item @code{nil} | ||
| 1824 | This glyph is simple. On an ordinary terminal, the glyph code mod 256 | ||
| 1825 | is the character to output. With X, the glyph code mod 256 is character | ||
| 1826 | to output, and the glyph code divided by 256 specifies the @dfn{face | ||
| 1827 | code} to use while outputting it. | ||
| 1828 | @end table | ||
| 1829 | |||
| 1830 | Any glyph code beyond the length of the glyph table is automatically simple. | ||
| 1831 | |||
| 1832 | A face code for X windows is the combination of a font and a color. | ||
| 1833 | Emacs uses integers to identify face codes. You can define a new face | ||
| 1834 | code with @code{(x-set-face @var{face-code} @var{font} @var{foreground} | ||
| 1835 | @var{background})}. @var{face-code} is an integer from 0 to 255; it | ||
| 1836 | specifies which face to define. The other three arguments are strings: | ||
| 1837 | @var{font} is the name of the font to use, and @var{foreground} and | ||
| 1838 | @var{background} specify the colors to use. | ||
| 1839 | |||
| 1840 | If @code{glyph-table} is @code{nil}, then all possible glyph codes are | ||
| 1841 | simple. | ||
| 1842 | |||
| 1843 | @subsection ISO Latin 1 | ||
| 1844 | |||
| 1845 | If you have a terminal that can handle the entire ISO Latin 1 character | ||
| 1846 | set, you can arrange to use that character set as follows: | ||
| 1847 | |||
| 1848 | @example | ||
| 1849 | (require 'disp-table) | ||
| 1850 | (standard-display-8bit 0 255) | ||
| 1851 | @end example | ||
| 1852 | |||
| 1853 | If you are editing buffers written in the ISO Latin 1 character set and | ||
| 1854 | your terminal doesn't handle anything but ASCII, you can load the file | ||
| 1855 | @code{iso-ascii} to set up a display table which makes the other ISO | ||
| 1856 | characters display as sequences of ASCII characters. For example, the | ||
| 1857 | character ``o with umlaut'' displays as @samp{@{"o@}}. | ||
| 1858 | |||
| 1859 | Some European countries have terminals that don't support ISO Latin 1 | ||
| 1860 | but do support the special characters for that country's language. You | ||
| 1861 | can define a display table to work one language using such terminals. | ||
| 1862 | For an example, see @file{lisp/iso-swed.el}, which handles certain | ||
| 1863 | Swedish terminals. | ||
| 1864 | |||
| 1865 | You can load the appropriate display table for your terminal | ||
| 1866 | automatically by writing a terminal-specific Lisp file for the terminal | ||
| 1867 | type. | ||
| 1868 | |||
| 1869 | @section New Input Event Formats | ||
| 1870 | |||
| 1871 | Mouse clicks, mouse movements and function keys no longer appear in the | ||
| 1872 | input stream as characters; instead, other kinds of Lisp objects | ||
| 1873 | represent them as input. | ||
| 1874 | |||
| 1875 | @itemize @bullet | ||
| 1876 | @item | ||
| 1877 | An ordinary input character event consists of a @dfn{basic code} between | ||
| 1878 | 0 and 255, plus any or all of these @dfn{modifier bits}: | ||
| 1879 | |||
| 1880 | @table @asis | ||
| 1881 | @item meta | ||
| 1882 | The 2**23 bit in the character code indicates a character | ||
| 1883 | typed with the meta key held down. | ||
| 1884 | |||
| 1885 | @item control | ||
| 1886 | The 2**22 bit in the character code indicates a non-@sc{ASCII} | ||
| 1887 | control character. | ||
| 1888 | |||
| 1889 | @sc{ASCII} control characters such as @kbd{C-a} have special basic | ||
| 1890 | codes of their own, so Emacs needs no special bit to indicate them. | ||
| 1891 | Thus, the code for @kbd{C-a} is just 1. | ||
| 1892 | |||
| 1893 | But if you type a control combination not in @sc{ASCII}, such as | ||
| 1894 | @kbd{%} with the control key, the numeric value you get is the code | ||
| 1895 | for @kbd{%} plus 2**22 (assuming the terminal supports non-@sc{ASCII} | ||
| 1896 | control characters). | ||
| 1897 | |||
| 1898 | @item shift | ||
| 1899 | The 2**21 bit in the character code indicates an @sc{ASCII} control | ||
| 1900 | character typed with the shift key held down. | ||
| 1901 | |||
| 1902 | For letters, the basic code indicates upper versus lower case; for | ||
| 1903 | digits and punctuation, the shift key selects an entirely different | ||
| 1904 | character with a different basic code. In order to keep within | ||
| 1905 | the @sc{ASCII} character set whenever possible, Emacs avoids using | ||
| 1906 | the 2**21 bit for those characters. | ||
| 1907 | |||
| 1908 | However, @sc{ASCII} provides no way to distinguish @kbd{C-A} from | ||
| 1909 | @kbd{C-A}, so Emacs uses the 2**21 bit in @kbd{C-A} and not in | ||
| 1910 | @kbd{C-a}. | ||
| 1911 | |||
| 1912 | @item hyper | ||
| 1913 | The 2**20 bit in the character code indicates a character | ||
| 1914 | typed with the hyper key held down. | ||
| 1915 | |||
| 1916 | @item super | ||
| 1917 | The 2**19 bit in the character code indicates a character | ||
| 1918 | typed with the super key held down. | ||
| 1919 | |||
| 1920 | @item alt | ||
| 1921 | The 2**18 bit in the character code indicates a character typed with | ||
| 1922 | the alt key held down. (On some terminals, the key labeled @key{ALT} | ||
| 1923 | is actually the meta key.) | ||
| 1924 | @end table | ||
| 1925 | |||
| 1926 | In the future, Emacs may support a larger range of basic codes. We may | ||
| 1927 | also move the modifier bits to larger bit numbers. Therefore, you | ||
| 1928 | should avoid mentioning specific bit numbers in your program. Instead, | ||
| 1929 | the way to test the modifier bits of a character is with the function | ||
| 1930 | @code{event-modifiers} (see below). | ||
| 1931 | |||
| 1932 | @item | ||
| 1933 | Function keys are represented as symbols. The symbol's name is | ||
| 1934 | the function key's label. For example, pressing a key labeled @key{F1} | ||
| 1935 | places the symbol @code{f1} in the input stream. | ||
| 1936 | |||
| 1937 | There are a few exceptions to the symbol naming convention: | ||
| 1938 | |||
| 1939 | @table @asis | ||
| 1940 | @item @code{kp-add}, @code{kp-decimal}, @code{kp-divide}, @dots{} | ||
| 1941 | Keypad keys (to the right of the regular keyboard). | ||
| 1942 | @item @code{kp-0}, @code{kp-1}, @dots{} | ||
| 1943 | Keypad keys with digits. | ||
| 1944 | @item @code{kp-f1}, @code{kp-f2}, @code{kp-f3}, @code{kp-f4} | ||
| 1945 | Keypad PF keys. | ||
| 1946 | @item @code{left}, @code{up}, @code{right}, @code{down} | ||
| 1947 | Cursor arrow keys | ||
| 1948 | @end table | ||
| 1949 | |||
| 1950 | You can use the modifier keys @key{CTRL}, @key{META}, @key{HYPER}, | ||
| 1951 | @key{SUPER}, @key{ALT} and @key{SHIFT} with function keys. The way | ||
| 1952 | to represent them is with prefixes in the symbol name: | ||
| 1953 | |||
| 1954 | @table @samp | ||
| 1955 | @item A- | ||
| 1956 | The alt modifier. | ||
| 1957 | @item C- | ||
| 1958 | The control modifier. | ||
| 1959 | @item H- | ||
| 1960 | The hyper modifier. | ||
| 1961 | @item M- | ||
| 1962 | The meta modifier. | ||
| 1963 | @item s- | ||
| 1964 | The super modifier. | ||
| 1965 | @item S- | ||
| 1966 | The shift modifier. | ||
| 1967 | @end table | ||
| 1968 | |||
| 1969 | Thus, the symbol for the key @key{F3} with @key{META} held down is | ||
| 1970 | kbd{M-@key{F3}}. When you use more than one prefix, we recommend you | ||
| 1971 | write them in alphabetical order (though the order does not matter in | ||
| 1972 | arguments to the key-binding lookup and modification functions). | ||
| 1973 | |||
| 1974 | @item | ||
| 1975 | Mouse events are represented as lists. | ||
| 1976 | |||
| 1977 | If you press a mouse button and release it at the same location, this | ||
| 1978 | generates a ``click'' event. Mouse click events have this form: | ||
| 1979 | |||
| 1980 | @example | ||
| 1981 | (@var{button-symbol} | ||
| 1982 | (@var{window} (@var{column} . @var{row}) | ||
| 1983 | @var{buffer-pos} @var{timestamp})) | ||
| 1984 | @end example | ||
| 1985 | |||
| 1986 | Here is what the elements normally mean: | ||
| 1987 | |||
| 1988 | @table @var | ||
| 1989 | @item button-symbol | ||
| 1990 | indicates which mouse button was used. It is one of the symbols | ||
| 1991 | @code{mouse-1}, @code{mouse-2}, @dots{}, where the buttons are numbered | ||
| 1992 | numbered left to right. | ||
| 1993 | |||
| 1994 | You can also use prefixes @samp{A-}, @samp{C-}, @samp{H-}, @samp{M-}, | ||
| 1995 | @samp{S-} and @samp{s-} for modifiers alt, control, hyper, meta, shift | ||
| 1996 | and super, just as you would with function keys. | ||
| 1997 | |||
| 1998 | @item window | ||
| 1999 | is the window in which the click occurred. | ||
| 2000 | |||
| 2001 | @item column | ||
| 2002 | @itemx row | ||
| 2003 | are the column and row of the click, relative to the top left corner of | ||
| 2004 | @var{window}, which is @code{(0 . 0)}. | ||
| 2005 | |||
| 2006 | @item buffer-pos | ||
| 2007 | is the buffer position of the character clicked on. | ||
| 2008 | |||
| 2009 | @item timestamp | ||
| 2010 | is the time at which the event occurred, in milliseconds. (Since this | ||
| 2011 | value wraps around the entire range of Emacs Lisp integers in about five | ||
| 2012 | hours, it is useful only for relating the times of nearby events.) | ||
| 2013 | @end table | ||
| 2014 | |||
| 2015 | The meanings of @var{buffer-pos}, @var{row} and @var{column} are | ||
| 2016 | somewhat different when the event location is in a special part of the | ||
| 2017 | screen, such as the mode line or a scroll bar. | ||
| 2018 | |||
| 2019 | If the position is in the window's scroll bar, then @var{buffer-pos} is | ||
| 2020 | the symbol @code{vertical-scrollbar} or @code{horizontal-scrollbar}, and | ||
| 2021 | the pair @code{(@var{column} . @var{row})} is instead a pair | ||
| 2022 | @code{(@var{portion} . @var{whole})}, where @var{portion} is the | ||
| 2023 | distance of the click from the top or left end of the scroll bar, and | ||
| 2024 | @var{whole} is the length of the entire scroll bar. | ||
| 2025 | |||
| 2026 | If the position is on a mode line or the vertical line separating | ||
| 2027 | @var{window} from its neighbor to the right, then @var{buffer-pos} is | ||
| 2028 | the symbol @code{mode-line} or @code{vertical-line}. In this case | ||
| 2029 | @var{row} and @var{column} do not have meaningful data. | ||
| 2030 | |||
| 2031 | @item | ||
| 2032 | Releasing a mouse button above a different character position | ||
| 2033 | generates a ``drag'' event, which looks like this: | ||
| 2034 | |||
| 2035 | @example | ||
| 2036 | (@var{button-symbol} | ||
| 2037 | (@var{window1} (@var{column1} . @var{row1}) | ||
| 2038 | @var{buffer-pos1} @var{timestamp1}) | ||
| 2039 | (@var{window2} (@var{column2} . @var{row2}) | ||
| 2040 | @var{buffer-pos2} @var{timestamp2})) | ||
| 2041 | @end example | ||
| 2042 | |||
| 2043 | The name of @var{button-symbol} contains the prefix @samp{drag-}. The | ||
| 2044 | second and third elements of the event give the starting and ending | ||
| 2045 | position of the drag. | ||
| 2046 | |||
| 2047 | The @samp{drag-} prefix follows the modifier key prefixes such as | ||
| 2048 | @samp{C-} and @samp{M-}. | ||
| 2049 | |||
| 2050 | If @code{read-key-sequence} receives a drag event which has no key | ||
| 2051 | binding, and the corresponding click event does have a binding, it | ||
| 2052 | changes the drag event into a click event at the drag's starting | ||
| 2053 | position. This means that you don't have to distinguish between click | ||
| 2054 | and drag events unless you want to. | ||
| 2055 | |||
| 2056 | @item | ||
| 2057 | Click and drag events happen when you release a mouse button. Another | ||
| 2058 | kind of event happens when you press a button. It looks just like a | ||
| 2059 | click event, except that the name of @var{button-symbol} contains the | ||
| 2060 | prefix @samp{down-}. The @samp{down-} prefix follows the modifier key | ||
| 2061 | prefixes such as @samp{C-} and @samp{M-}. | ||
| 2062 | |||
| 2063 | The function @code{read-key-sequence}, and the Emacs command loop, | ||
| 2064 | ignore any down events that don't have command bindings. This means | ||
| 2065 | that you need not worry about defining down events unless you want them | ||
| 2066 | to do something. The usual reason to define a down event is so that you | ||
| 2067 | can track mouse motion until the button is released. | ||
| 2068 | |||
| 2069 | @item | ||
| 2070 | For example, if the user presses and releases the left mouse button over | ||
| 2071 | the same location, Emacs generates a sequence of events like this: | ||
| 2072 | |||
| 2073 | @smallexample | ||
| 2074 | (down-mouse-1 (#<window 18 on NEWS> 2613 (0 . 38) -864320)) | ||
| 2075 | (mouse-1 (#<window 18 on NEWS> 2613 (0 . 38) -864180)) | ||
| 2076 | @end smallexample | ||
| 2077 | |||
| 2078 | Or, while holding the control key down, the user might hold down the | ||
| 2079 | second mouse button, and drag the mouse from one line to the next. | ||
| 2080 | That produces two events, as shown here: | ||
| 2081 | |||
| 2082 | @smallexample | ||
| 2083 | (C-down-mouse-2 (#<window 18 on NEWS> 3440 (0 . 27) -731219)) | ||
| 2084 | (C-drag-mouse-2 (#<window 18 on NEWS> 3440 (0 . 27) -731219) | ||
| 2085 | (#<window 18 on NEWS> 3510 (0 . 28) -729648)) | ||
| 2086 | @end smallexample | ||
| 2087 | |||
| 2088 | Or, while holding down the meta and shift keys, the user might press | ||
| 2089 | the second mouse button on the window's mode line, and then drag the | ||
| 2090 | mouse into another window. That produces an event like this: | ||
| 2091 | |||
| 2092 | @smallexample | ||
| 2093 | (M-S-down-mouse-2 (#<window 18 on NEWS> mode-line (33 . 31) -457844)) | ||
| 2094 | (M-S-drag-mouse-2 (#<window 18 on NEWS> mode-line (33 . 31) -457844) | ||
| 2095 | (#<window 20 on carlton-sanskrit.tex> 161 (33 . 3) | ||
| 2096 | -453816)) | ||
| 2097 | @end smallexample | ||
| 2098 | |||
| 2099 | @item | ||
| 2100 | A key sequence that starts with a mouse click is read using the keymaps | ||
| 2101 | of the buffer in the window clicked on, not the current buffer. | ||
| 2102 | |||
| 2103 | This does not imply that clicking in a window selects that window or its | ||
| 2104 | buffer. The execution of the command begins with no change in the | ||
| 2105 | selected window or current buffer. However, the command can switch | ||
| 2106 | windows or buffers if programmed to do so. | ||
| 2107 | |||
| 2108 | @item | ||
| 2109 | Mouse motion events are represented by lists. During the execution of | ||
| 2110 | the body of a @code{track-mouse} form, moving the mouse generates events | ||
| 2111 | that look like this: | ||
| 2112 | |||
| 2113 | @example | ||
| 2114 | (mouse-movement (@var{window} (@var{column} . @var{row}) | ||
| 2115 | @var{buffer-pos} @var{timestamp})) | ||
| 2116 | @end example | ||
| 2117 | |||
| 2118 | The second element of the list describes the current position of the | ||
| 2119 | mouse, just as in a mouse click event. | ||
| 2120 | |||
| 2121 | Outside of @code{track-mouse} forms, Emacs does not generate events for | ||
| 2122 | mere motion of the mouse, and these events do not appear. | ||
| 2123 | |||
| 2124 | @item | ||
| 2125 | Focus shifts between frames are represented by lists. | ||
| 2126 | |||
| 2127 | When the mouse shifts temporary input focus from one frame to another, | ||
| 2128 | Emacs generates an event like this: | ||
| 2129 | |||
| 2130 | @example | ||
| 2131 | (switch-frame @var{new-frame}) | ||
| 2132 | @end example | ||
| 2133 | |||
| 2134 | @noindent | ||
| 2135 | where @var{new-frame} is the frame switched to. | ||
| 2136 | |||
| 2137 | In X windows, most window managers are set up so that just moving the | ||
| 2138 | mouse into a window is enough to set the focus there. As far as the | ||
| 2139 | user concern, Emacs behaves consistently with this. However, there is | ||
| 2140 | no need for the Lisp program to know about the focus change until some | ||
| 2141 | other kind of input arrives. So Emacs generates the focus event only | ||
| 2142 | when the user actually types a keyboard key or presses a mouse button in | ||
| 2143 | the new frame; just moving the mouse between frames does not generate a | ||
| 2144 | focus event. | ||
| 2145 | |||
| 2146 | The global key map usually binds this event to the | ||
| 2147 | @code{internal-select-frame} function, so that characters typed at a | ||
| 2148 | frame apply to that frame's selected window. | ||
| 2149 | |||
| 2150 | If the user switches frames in the middle of a key sequence, then Emacs | ||
| 2151 | delays the @code{switch-frame} event until the key sequence is over. | ||
| 2152 | For example, suppose @kbd{C-c C-a} is a key sequence in the current | ||
| 2153 | buffer's keymaps. If the user types @kbd{C-c}, moves the mouse to | ||
| 2154 | another frame, and then types @kbd{C-a}, @code{read-key-sequence} | ||
| 2155 | returns the sequence @code{"\C-c\C-a"}, and the next call to | ||
| 2156 | @code{read-event} or @code{read-key-sequence} will return the | ||
| 2157 | @code{switch-frame} event. | ||
| 2158 | @end itemize | ||
| 2159 | |||
| 2160 | @section Working with Input Events | ||
| 2161 | |||
| 2162 | @itemize @bullet | ||
| 2163 | @item | ||
| 2164 | Functions which work with key sequences now handle non-character | ||
| 2165 | events. Functions like @code{define-key}, @code{global-set-key}, and | ||
| 2166 | @code{local-set-key} used to accept strings representing key sequences; | ||
| 2167 | now, since events may be arbitrary lisp objects, they also accept | ||
| 2168 | vectors. The function @code{read-key-sequence} may return a string or a | ||
| 2169 | vector, depending on whether or not the sequence read contains only | ||
| 2170 | characters. | ||
| 2171 | |||
| 2172 | List events may be represented by the symbols at their head; to bind | ||
| 2173 | clicks of the left mouse button, you need only present the symbol | ||
| 2174 | @code{mouse-1}, not an entire mouse click event. If you do put an event | ||
| 2175 | which is a list in a key sequence, only the event's head symbol is used | ||
| 2176 | in key lookups. | ||
| 2177 | |||
| 2178 | For example, to globally bind the left mouse button to the function | ||
| 2179 | @code{mouse-set-point}, you could evaluate this: | ||
| 2180 | |||
| 2181 | @example | ||
| 2182 | (global-set-key [mouse-1] 'mouse-set-point) | ||
| 2183 | @end example | ||
| 2184 | |||
| 2185 | To bind the sequence @kbd{C-c @key{F1}} to the command @code{tex-view} | ||
| 2186 | in @code{tex-mode-map}, you could evaluate this: | ||
| 2187 | |||
| 2188 | @example | ||
| 2189 | (define-key tex-mode-map [?\C-c f1] 'tex-view) | ||
| 2190 | @end example | ||
| 2191 | |||
| 2192 | To find the binding for the function key labeled @key{NEXT} in | ||
| 2193 | @code{minibuffer-local-map}, you could evaluate this: | ||
| 2194 | |||
| 2195 | @example | ||
| 2196 | (lookup-key minibuffer-local-map [next]) | ||
| 2197 | @result{} next-history-element | ||
| 2198 | @end example | ||
| 2199 | |||
| 2200 | If you call the function @code{read-key-sequence} and then press | ||
| 2201 | @kbd{C-x C-@key{F5}}, here is how it behaves: | ||
| 2202 | |||
| 2203 | @example | ||
| 2204 | (read-key-sequence "Press `C-x C-F5': ") | ||
| 2205 | @result{} [24 C-f5] | ||
| 2206 | @end example | ||
| 2207 | |||
| 2208 | Note that @samp{24} is the character @kbd{C-x}. | ||
| 2209 | |||
| 2210 | @item | ||
| 2211 | The documentation functions (@code{single-key-description}, | ||
| 2212 | @code{key-description}, etc.) now handle the new event types. Wherever | ||
| 2213 | a string of keyboard input characters was acceptable in previous | ||
| 2214 | versions of Emacs, a vector of events should now work. | ||
| 2215 | |||
| 2216 | @item | ||
| 2217 | Special parts of a window can have their own bindings for mouse events. | ||
| 2218 | |||
| 2219 | When mouse events occur in special parts of a window, such as a mode | ||
| 2220 | line or a scroll bar, the event itself shows nothing special---only the | ||
| 2221 | symbol that would normally represent that mouse button and modifier | ||
| 2222 | keys. The information about the screen region is kept in other parts | ||
| 2223 | of the event list. But @code{read-key-sequence} translates this | ||
| 2224 | information into imaginary prefix keys, all of which are symbols: | ||
| 2225 | @code{mode-line}, @code{vertical-line}, @code{horizontal-scrollbar} and | ||
| 2226 | @code{vertical-scrollbar}. | ||
| 2227 | |||
| 2228 | For example, if you call @code{read-key-sequence} and then click the | ||
| 2229 | mouse on the window's mode line, this is what happens: | ||
| 2230 | |||
| 2231 | @smallexample | ||
| 2232 | (read-key-sequence "Click on the mode line: ") | ||
| 2233 | @result{} [mode-line (mouse-1 (#<window 6 on NEWS> mode-line | ||
| 2234 | (40 . 63) 5959987))] | ||
| 2235 | @end smallexample | ||
| 2236 | |||
| 2237 | You can define meanings for mouse clicks in special window regions by | ||
| 2238 | defining key sequences using these imaginary prefix keys. For example, | ||
| 2239 | here is how to bind the third mouse button on a window's mode line | ||
| 2240 | delete the window: | ||
| 2241 | |||
| 2242 | @example | ||
| 2243 | (global-set-key [mode-line mouse-3] 'mouse-delete-window) | ||
| 2244 | @end example | ||
| 2245 | |||
| 2246 | Here's how to bind the middle button (modified by @key{META}) on the | ||
| 2247 | vertical line at the right of a window to scroll the window to the | ||
| 2248 | left. | ||
| 2249 | |||
| 2250 | @example | ||
| 2251 | (global-set-key [vertical-line M-mouse-2] 'scroll-left) | ||
| 2252 | @end example | ||
| 2253 | |||
| 2254 | @item | ||
| 2255 | Decomposing an event symbol. | ||
| 2256 | |||
| 2257 | Each symbol used to identify a function key or mouse button has a | ||
| 2258 | property named @code{event-symbol-elements}, which is a list containing | ||
| 2259 | an unmodified version of the symbol, followed by modifiers the symbol | ||
| 2260 | name contains. The modifiers are symbols; they include @code{shift}, | ||
| 2261 | @code{control}, and @code{meta}. In addition, a mouse event symbol has | ||
| 2262 | one of @code{click}, @code{drag}, and @code{down}. For example: | ||
| 2263 | |||
| 2264 | @example | ||
| 2265 | (get 'f5 'event-symbol-elements) | ||
| 2266 | @result{} (f5) | ||
| 2267 | (get 'C-f5 'event-symbol-elements) | ||
| 2268 | @result{} (f5 control) | ||
| 2269 | (get 'M-S-f5 'event-symbol-elements) | ||
| 2270 | @result{} (f5 meta shift) | ||
| 2271 | (get 'mouse-1 'event-symbol-elements) | ||
| 2272 | @result{} (mouse-1 click) | ||
| 2273 | (get 'down-mouse-1 'event-symbol-elements) | ||
| 2274 | @result{} (mouse-1 down) | ||
| 2275 | @end example | ||
| 2276 | |||
| 2277 | Note that the @code{event-symbol-elements} property for a mouse click | ||
| 2278 | explicitly contains @code{click}, but the event symbol name itself does | ||
| 2279 | not contain @samp{click}. | ||
| 2280 | |||
| 2281 | @item | ||
| 2282 | Use @code{read-event} to read input if you want to accept any kind of | ||
| 2283 | event. The old function @code{read-char} now discards events other than | ||
| 2284 | keyboard characters. | ||
| 2285 | |||
| 2286 | @item | ||
| 2287 | @code{last-command-char} and @code{last-input-char} can now hold any | ||
| 2288 | kind of event. | ||
| 2289 | |||
| 2290 | @item | ||
| 2291 | The new variable @code{unread-command-events} is much like | ||
| 2292 | @code{unread-command-char}. Its value is a list of events of any type, | ||
| 2293 | to be processed as command input in order of appearance in the list. | ||
| 2294 | |||
| 2295 | @item | ||
| 2296 | The function @code{this-command-keys} may return a string or a vector, | ||
| 2297 | depending on whether or not the sequence read contains only characters. | ||
| 2298 | You may need to upgrade code which uses this function. | ||
| 2299 | |||
| 2300 | The function @code{recent-keys} now returns a vector of events. | ||
| 2301 | You may need to upgrade code which uses this function. | ||
| 2302 | |||
| 2303 | @item | ||
| 2304 | A keyboard macro's definition can now be either a string or a vector. | ||
| 2305 | All that really matters is what elements it has. If the elements are | ||
| 2306 | all characters, then the macro can be a string; otherwise, it has to be | ||
| 2307 | a vector. | ||
| 2308 | |||
| 2309 | @item | ||
| 2310 | The variable @code{last-event-frame} records which frame the last input | ||
| 2311 | event was directed to. Usually this is the frame that was selected when | ||
| 2312 | the event was generated, but if that frame has redirected input focus to | ||
| 2313 | another frame, @code{last-event-frame} is the frame to which the event | ||
| 2314 | was redirected. | ||
| 2315 | |||
| 2316 | @item | ||
| 2317 | The interactive specification now allows a new code letter @samp{e} to | ||
| 2318 | simplify commands bound to events which are lists. This code supplies | ||
| 2319 | as an argument the complete event object. | ||
| 2320 | |||
| 2321 | You can use @samp{e} more than once in a single command's interactive | ||
| 2322 | specification. If the key sequence which invoked the command has | ||
| 2323 | @var{n} events with parameters, the @var{n}th @samp{e} provides the | ||
| 2324 | @var{n}th parameterized event. Events which are not lists, such as | ||
| 2325 | function keys and ASCII keystrokes, do not count where @samp{e} is | ||
| 2326 | concerned. | ||
| 2327 | |||
| 2328 | @item | ||
| 2329 | You can extract the starting and ending position values from a mouse | ||
| 2330 | button or motion event using the two functions @code{event-start} and | ||
| 2331 | @code{event-end}. These two functions return different values for drag | ||
| 2332 | and motion events; for click and button-down events, they both return | ||
| 2333 | the position of the event. | ||
| 2334 | |||
| 2335 | @item | ||
| 2336 | The position, a returned by @code{event-start} and @code{event-end}, is | ||
| 2337 | a list of this form: | ||
| 2338 | |||
| 2339 | @example | ||
| 2340 | (@var{window} @var{buffer-position} (@var{col} . @var{row}) @var{timestamp}) | ||
| 2341 | @end example | ||
| 2342 | |||
| 2343 | You can extract parts of this list with the functions | ||
| 2344 | @code{posn-window}, @code{posn-point}, @code{posn-col-row}, and | ||
| 2345 | @code{posn-timestamp}. | ||
| 2346 | |||
| 2347 | @item | ||
| 2348 | The function @code{scroll-bar-scale} is useful for computing where to | ||
| 2349 | scroll to in response to a mouse button event from a scroll bar. It | ||
| 2350 | takes two arguments, @var{ratio} and @var{total}, and in effect | ||
| 2351 | multiplies them. We say ``in effect'' because @var{ratio} is not a | ||
| 2352 | number; rather a pair @code{(@var{num} . @var{denom}). | ||
| 2353 | |||
| 2354 | Here's the usual way to use @code{scroll-bar-scale}: | ||
| 2355 | |||
| 2356 | @example | ||
| 2357 | (scroll-bar-scale (posn-col-row (event-start event)) | ||
| 2358 | (buffer-size)) | ||
| 2359 | @end example | ||
| 2360 | @end itemize | ||
| 2361 | |||
| 2362 | @section Putting Keyboard Events in Strings | ||
| 2363 | |||
| 2364 | In most of the places where strings are used, we conceptualize the | ||
| 2365 | string as containing text characters---the same kind of characters found | ||
| 2366 | in buffers or files. Occasionally Lisp programs use strings which | ||
| 2367 | conceptually contain keyboard characters; for example, they may be key | ||
| 2368 | sequences or keyboard macro definitions. There are special rules for | ||
| 2369 | how to put keyboard characters into a string, because they are not | ||
| 2370 | limited to the range of 0 to 255 as text characters are. | ||
| 2371 | |||
| 2372 | A keyboard character typed using the @key{META} key is called a | ||
| 2373 | @dfn{meta character}. The numeric code for such an event includes the | ||
| 2374 | 2**23 bit; it does not even come close to fitting in a string. However, | ||
| 2375 | earlier Emacs versions used a different representation for these | ||
| 2376 | characters, which gave them codes in the range of 128 to 255. That did | ||
| 2377 | fit in a string, and many Lisp programs contain string constants that | ||
| 2378 | use @samp{\M-} to express meta characters, especially as the argument to | ||
| 2379 | @code{define-key} and similar functions. | ||
| 2380 | |||
| 2381 | We provide backward compatibility to run those programs with special | ||
| 2382 | rules for how to put a keyboard character event in a string. Here are | ||
| 2383 | the rules: | ||
| 2384 | |||
| 2385 | @itemize @bullet | ||
| 2386 | @item | ||
| 2387 | If the keyboard event value is in the range of 0 to 127, it can go in the | ||
| 2388 | string unchanged. | ||
| 2389 | |||
| 2390 | @item | ||
| 2391 | The meta variants of those events, with codes in the range of 2**23 to | ||
| 2392 | 2**23+127, can also go in the string, but you must change their numeric | ||
| 2393 | values. You must set the 2**7 bit instead of the 2**23 bit, resulting | ||
| 2394 | in a value between 128 and 255. | ||
| 2395 | |||
| 2396 | @item | ||
| 2397 | Other keyboard character events cannot fit in a string. This includes | ||
| 2398 | keyboard events in the range of 128 to 255. | ||
| 2399 | @end itemize | ||
| 2400 | |||
| 2401 | Functions such as @code{read-key-sequence} that can construct strings | ||
| 2402 | containing events follow these rules. | ||
| 2403 | |||
| 2404 | When you use the read syntax @samp{\M-} in a string, it produces a | ||
| 2405 | code in the range of 128 to 255---the same code that you get if you | ||
| 2406 | modify the corresponding keyboard event to put it in the string. Thus, | ||
| 2407 | meta events in strings work consistently regardless of how they get into | ||
| 2408 | the strings. | ||
| 2409 | |||
| 2410 | New programs can avoid dealing with these rules by using vectors | ||
| 2411 | instead of strings for key sequences when there is any possibility that | ||
| 2412 | these issues might arise. | ||
| 2413 | |||
| 2414 | The reason we changed the representation of meta characters as | ||
| 2415 | keyboard events is to make room for basic character codes beyond 127, | ||
| 2416 | and support meta variants of such larger character codes. | ||
| 2417 | |||
| 2418 | @section Menus | ||
| 2419 | |||
| 2420 | You can now define menus conveniently as keymaps. Menus are normally | ||
| 2421 | used with the mouse, but they can work with the keyboard also. | ||
| 2422 | |||
| 2423 | @subsection Defining Menus | ||
| 2424 | |||
| 2425 | A keymap is suitable for menu use if it has an @dfn{overall prompt | ||
| 2426 | string}, which is a string that appears as an element of the keymap. It | ||
| 2427 | should describes the purpose of the menu. The easiest way to construct | ||
| 2428 | a keymap with a prompt string is to specify the string as an argument | ||
| 2429 | when you run @code{make-keymap} or @code{make-sparse-keymap}. | ||
| 2430 | |||
| 2431 | The individual bindings in the menu keymap should also have prompt | ||
| 2432 | strings; these strings are the items in the menu. A binding with a | ||
| 2433 | prompt string looks like this: | ||
| 2434 | |||
| 2435 | @example | ||
| 2436 | (@var{char} @var{string} . @var{real-binding}) | ||
| 2437 | @end example | ||
| 2438 | |||
| 2439 | As far as @code{define-key} is concerned, the string is part of the | ||
| 2440 | character's binding---the binding looks like this: | ||
| 2441 | |||
| 2442 | @example | ||
| 2443 | (@var{string} . @var{real-binding}). | ||
| 2444 | @end example | ||
| 2445 | |||
| 2446 | However, only @var{real-binding} is used for executing the key. | ||
| 2447 | |||
| 2448 | You can also supply a second string, called the help string, as follows: | ||
| 2449 | |||
| 2450 | @example | ||
| 2451 | (@var{char} @var{string} @var{help-string} . @var{real-binding}) | ||
| 2452 | @end example | ||
| 2453 | |||
| 2454 | Currently Emacs does not actually use @var{help-string}; it knows only | ||
| 2455 | how to ignore @var{help-string} in order to extract @var{real-binding}. | ||
| 2456 | In the future we hope to make @var{help-string} serve as longer | ||
| 2457 | documentation for the menu item, available on request. | ||
| 2458 | |||
| 2459 | The prompt string for a binding should be short---one or two words. Its | ||
| 2460 | meaning should describe the command it corresponds to. | ||
| 2461 | |||
| 2462 | If @var{real-binding} is @code{nil}, then @var{string} appears in the | ||
| 2463 | menu but cannot be selected. | ||
| 2464 | |||
| 2465 | If @var{real-binding} is a symbol, and has a non-@code{nil} | ||
| 2466 | @code{menu-enable} property, that property is an expression which | ||
| 2467 | controls whether the menu item is enabled. Every time the keymap is | ||
| 2468 | used to display a menu, Emacs evaluates the expression, and it enables | ||
| 2469 | the menu item only if the expression's value is non-@code{nil}. When a | ||
| 2470 | menu item is disabled, it is displayed in a ``fuzzy'' fashion, and | ||
| 2471 | cannot be selected with the mouse. | ||
| 2472 | |||
| 2473 | @subsection Menus and the Mouse | ||
| 2474 | |||
| 2475 | The way to make a menu keymap produce a menu is to make it the | ||
| 2476 | definition of a prefix key. | ||
| 2477 | |||
| 2478 | When the prefix key ends with a mouse event, Emacs handles the menu | ||
| 2479 | keymap by popping up a visible menu that you can select from with the | ||
| 2480 | mouse. When you click on a menu item, the event generated is whatever | ||
| 2481 | character or symbol has the binding which brought about that menu item. | ||
| 2482 | |||
| 2483 | A single keymap can appear as multiple panes, if you explicitly | ||
| 2484 | arrange for this. The way to do this is to make a keymap for each | ||
| 2485 | pane, then create a binding for each of those maps in the main keymap | ||
| 2486 | of the menu. Give each of these bindings a prompt string that starts | ||
| 2487 | with @samp{@@}. The rest of the prompt string becomes the name of the | ||
| 2488 | pane. See the file @file{lisp/mouse.el} for an example of this. Any | ||
| 2489 | ordinary bindings with prompt strings are grouped into one pane, which | ||
| 2490 | appears along with the other panes explicitly created for the | ||
| 2491 | submaps. | ||
| 2492 | |||
| 2493 | You can also get multiple panes from separate keymaps. The full | ||
| 2494 | definition of a prefix key always comes from merging the definitions | ||
| 2495 | supplied by the various active keymaps (minor modes, local, and | ||
| 2496 | global). When more than one of these keymaps is a menu, each of them | ||
| 2497 | makes a separate pane or panes. | ||
| 2498 | |||
| 2499 | @subsection Menus and the Keyboard | ||
| 2500 | |||
| 2501 | When a prefix key ending with a keyboard event (a character or function | ||
| 2502 | key) has a definition that is a menu keymap, you can use the keyboard | ||
| 2503 | to choose a menu item. | ||
| 2504 | |||
| 2505 | Emacs displays the menu alternatives in the echo area. If they don't | ||
| 2506 | all fit at once, type @key{SPC} to see the next line of alternatives. | ||
| 2507 | If you keep typing @key{SPC}, you eventually get to the end of the menu | ||
| 2508 | and then cycle around to the beginning again. | ||
| 2509 | |||
| 2510 | When you have found the alternative you want, type the corresponding | ||
| 2511 | character---the one whose binding is that alternative. | ||
| 2512 | |||
| 2513 | In a menu intended for keyboard use, each menu item must clearly | ||
| 2514 | indicate what character to type. The best convention to use is to make | ||
| 2515 | the character the first letter of the menu item prompt string. That is | ||
| 2516 | something users will understand without being told. | ||
| 2517 | |||
| 2518 | @subsection The Menu Bar | ||
| 2519 | |||
| 2520 | Under X Windows, each frame can have a @dfn{menu bar}---a permanently | ||
| 2521 | displayed menu stretching horizontally across the top of the frame. The | ||
| 2522 | items of the menu bar are the subcommands of the fake ``function key'' | ||
| 2523 | @code{menu-bar}, as defined by all the active keymaps. | ||
| 2524 | |||
| 2525 | To add an item to the menu bar, invent a fake ``function key'' of your | ||
| 2526 | own (let's call it @var{key}), and make a binding for the key sequence | ||
| 2527 | @code{[menu-bar @var{key}]}. Most often, the binding is a menu keymap, | ||
| 2528 | so that pressing a button on the menu bar item leads to another menu. | ||
| 2529 | |||
| 2530 | In order for a frame to display a menu bar, its @code{menu-bar-lines} | ||
| 2531 | property must be greater than zero. Emacs uses just one line for the | ||
| 2532 | menu bar itself; if you specify more than one line, the other lines | ||
| 2533 | serve to separate the menu bar from the windows in the frame. We | ||
| 2534 | recommend you try one or two as the @code{menu-bar-lines} value. | ||
| 2535 | |||
| 2536 | @section Keymaps | ||
| 2537 | |||
| 2538 | @itemize @bullet | ||
| 2539 | @item | ||
| 2540 | The representation of keymaps has changed to support the new event | ||
| 2541 | types. All keymaps now have the form @code{(keymap @var{element} | ||
| 2542 | @var{element} @dots{})}. Each @var{element} takes one of the following | ||
| 2543 | forms: | ||
| 2544 | |||
| 2545 | @table @asis | ||
| 2546 | @item @var{prompt-string} | ||
| 2547 | A string as an element of the keymap marks the keymap as a menu, and | ||
| 2548 | serves as the overal prompt string for it. | ||
| 2549 | |||
| 2550 | @item @code{(@var{key} . @var{binding})} | ||
| 2551 | A cons cell binds @var{key} to @var{definition}. Here @var{key} may be | ||
| 2552 | any sort of event head---a character, a function key symbol, or a mouse | ||
| 2553 | button symbol. | ||
| 2554 | |||
| 2555 | @item @var{vector} | ||
| 2556 | A vector of 128 elements binds all the ASCII characters; the @var{n}th | ||
| 2557 | element holds the binding for character number @var{n}. | ||
| 2558 | |||
| 2559 | @item @code{(t . @var{binding})} | ||
| 2560 | A cons cell whose @sc{car} is @code{t} is a default binding; anything | ||
| 2561 | not bound by previous keymap elements is given @var{binding} as its | ||
| 2562 | binding. | ||
| 2563 | |||
| 2564 | Default bindings are important because they allow a keymap to bind all | ||
| 2565 | possible events without having to enumerate all the possible function | ||
| 2566 | keys and mouse clicks, with all possible modifier prefixes. | ||
| 2567 | |||
| 2568 | The function @code{lookup-key} (and likewise other functions for | ||
| 2569 | examining a key binding) normally report only explicit bindings of the | ||
| 2570 | specified key sequence; if there is none, they return @code{nil}, even | ||
| 2571 | if there is a default binding that would apply to that key sequence if | ||
| 2572 | it were actually typed in. However, these functions now take an | ||
| 2573 | optional argument @var{accept-defaults} which, if non-@code{nil}, says | ||
| 2574 | to consider default bindings. | ||
| 2575 | |||
| 2576 | Note that if a vector in the keymap binds an ASCII character to | ||
| 2577 | @code{nil} (thus making it ``unbound''), the default binding does not | ||
| 2578 | apply to the character. Think of the vector element as an explicit | ||
| 2579 | binding of @code{nil}. | ||
| 2580 | |||
| 2581 | Note also that if the keymap for a minor or major mode contains a | ||
| 2582 | default binding, it completely masks out any lower-priority keymaps. | ||
| 2583 | @end table | ||
| 2584 | |||
| 2585 | @item | ||
| 2586 | A keymap can now inherit from another keymap. Do do this, make the | ||
| 2587 | latter keymap the ``tail'' of the new one. Such a keymap looks like | ||
| 2588 | this: | ||
| 2589 | |||
| 2590 | @example | ||
| 2591 | (keymap @var{bindings}@dots{} . @var{other-keymap}) | ||
| 2592 | @end example | ||
| 2593 | |||
| 2594 | The effect is that this keymap inherits all the bindings of | ||
| 2595 | @var{other-keymap}, but can add to them or override them with | ||
| 2596 | @var{bindings}. Subsequent changes in the bindings of | ||
| 2597 | @var{other-keymap} @emph{do} affect this keymap. | ||
| 2598 | |||
| 2599 | For example, | ||
| 2600 | |||
| 2601 | @example | ||
| 2602 | (setq my-mode-map (cons 'keymap text-mode-map)) | ||
| 2603 | @end example | ||
| 2604 | |||
| 2605 | @noindent | ||
| 2606 | makes a keymap that by default inherits all the bindings of Text | ||
| 2607 | mode---whatever they may be at the time a key is looked up. Any | ||
| 2608 | bindings made explicitly in @code{my-mode-map} override the bindings | ||
| 2609 | inherited from Text mode, however. | ||
| 2610 | |||
| 2611 | @item | ||
| 2612 | Minor modes can now have local keymaps. Thus, a key can act a special | ||
| 2613 | way when a minor mode is in effect, and then revert to the major mode or | ||
| 2614 | global definition when the minor mode is no longer in effect. The | ||
| 2615 | precedence of keymaps is now: minor modes (in no particular order), then | ||
| 2616 | major mode, and lastly the global map. | ||
| 2617 | |||
| 2618 | The new @code{current-minor-mode-maps} function returns a list of all | ||
| 2619 | the keymaps of currently enabled minor modes, in the other that they | ||
| 2620 | apply. | ||
| 2621 | |||
| 2622 | To set up a keymap for a minor mode, add an element to the alist | ||
| 2623 | @code{minor-mode-map-alist}. Its elements look like this: | ||
| 2624 | |||
| 2625 | @example | ||
| 2626 | (@var{symbol} . @var{keymap}) | ||
| 2627 | @end example | ||
| 2628 | |||
| 2629 | The keymap @var{keymap} is active whenever @var{symbol} has a | ||
| 2630 | non-@code{nil} value. Use for @var{symbol} the variable which indicates | ||
| 2631 | whether the minor mode is enabled. | ||
| 2632 | |||
| 2633 | When more than one minor mode keymap is active, their order of | ||
| 2634 | precedence is the order of @code{minor-mode-map-alist}. But you should | ||
| 2635 | design minor modes so that they don't interfere with each other, and if | ||
| 2636 | you do this properly, the order will not matter. | ||
| 2637 | |||
| 2638 | The function @code{minor-mode-key-binding} returns a list of all the | ||
| 2639 | active minor mode bindings of @var{key}. More precisely, it returns an | ||
| 2640 | alist of pairs @code{(@var{modename} . @var{binding})}, where | ||
| 2641 | @var{modename} is the the variable which enables the minor mode, and | ||
| 2642 | @var{binding} is @var{key}'s definition in that mode. If @var{key} has | ||
| 2643 | no minor-mode bindings, the value is @code{nil}. | ||
| 2644 | |||
| 2645 | If the first binding is a non-prefix, all subsequent bindings from other | ||
| 2646 | minor modes are omitted, since they would be completely shadowed. | ||
| 2647 | Similarly, the list omits non-prefix bindings that follow prefix | ||
| 2648 | bindings. | ||
| 2649 | |||
| 2650 | @item | ||
| 2651 | The new function @code{copy-keymap} copies a keymap, producing a new | ||
| 2652 | keymap with the same key bindings in it. If the keymap contains other | ||
| 2653 | keymaps directly, these subkeymaps are copied recursively. | ||
| 2654 | |||
| 2655 | If you want to, you can define a prefix key with a binding that is a | ||
| 2656 | symbol whose function definition is another keymap. In this case, | ||
| 2657 | @code{copy-keymap} does not look past the symbol; it doesn't copy the | ||
| 2658 | keymap inside the symbol. | ||
| 2659 | |||
| 2660 | @item | ||
| 2661 | @code{substitute-key-definition} now accepts an optional fourth | ||
| 2662 | argument, which is a keymap to use as a template. | ||
| 2663 | |||
| 2664 | @example | ||
| 2665 | (substitute-key-definition olddef newdef keymap oldmap) | ||
| 2666 | @end example | ||
| 2667 | |||
| 2668 | @noindent | ||
| 2669 | finds all characters defined in @var{oldmap} as @var{olddef}, | ||
| 2670 | and defines them in @var{keymap} as @var{newdef}. | ||
| 2671 | |||
| 2672 | In addition, this function now operates recursively on the keymaps that | ||
| 2673 | define prefix keys within @var{keymap} and @var{oldmap}. | ||
| 2674 | @end itemize | ||
| 2675 | |||
| 2676 | @section Minibuffer Features | ||
| 2677 | |||
| 2678 | The minibuffer input functions @code{read-from-minibuffer} and | ||
| 2679 | @code{completing-read} have new features. | ||
| 2680 | |||
| 2681 | @subsection Minibuffer History | ||
| 2682 | |||
| 2683 | A new optional argument @var{hist} specifies which history list to use. | ||
| 2684 | If you specify a variable (a symbol), that variable is the history | ||
| 2685 | list. If you specify a cons cell @code{(@var{variable} | ||
| 2686 | . @var{startpos})}, then @var{variable} is the history list variable, | ||
| 2687 | and @var{startpos} specifies the initial history position (an integer, | ||
| 2688 | counting from zero which specifies the most recent element of the | ||
| 2689 | history). | ||
| 2690 | |||
| 2691 | If you specify @var{startpos}, then you should also specify that element | ||
| 2692 | of the history as @var{initial-input}, for consistency. | ||
| 2693 | |||
| 2694 | If you don't specify @var{hist}, then the default history list | ||
| 2695 | @code{minibuffer-history} is used. Other standard history lists that | ||
| 2696 | you can use when appropriate include @code{query-replace-history}, | ||
| 2697 | @code{command-history}, and @code{file-name-history}. | ||
| 2698 | |||
| 2699 | The value of the history list variable is a list of strings, most recent | ||
| 2700 | first. You should set a history list variable to @code{nil} before | ||
| 2701 | using it for the first time. | ||
| 2702 | |||
| 2703 | @code{read-from-minibuffer} and @code{completing-read} add new elements | ||
| 2704 | to the history list automatically, and provide commands to allow the | ||
| 2705 | user to reuse items on the list. The only thing your program needs to | ||
| 2706 | do to use a history list is to initialize it and to pass its name to the | ||
| 2707 | input functions when you wish. But it is safe to modify the list by | ||
| 2708 | hand when the minibuffer input functions are not using it. | ||
| 2709 | |||
| 2710 | @subsection Other Minibuffer Features | ||
| 2711 | |||
| 2712 | The @var{initial} argument to @code{read-from-minibufer} and other | ||
| 2713 | minibuffer input functions can now be a cons cell @code{(@var{string} | ||
| 2714 | . @var{position})}. This means to start off with @var{string} in the | ||
| 2715 | minibuffer, but put the cursor @var{position} characters from the | ||
| 2716 | beginning, rather than at the end. | ||
| 2717 | |||
| 2718 | In @code{read-no-blanks-input}, the @var{initial} argument is now | ||
| 2719 | optional; if it is omitted, the initial input string is the empty | ||
| 2720 | string. | ||
| 2721 | |||
| 2722 | @section New Features for Defining Commands | ||
| 2723 | |||
| 2724 | @itemize @bullet | ||
| 2725 | @item | ||
| 2726 | If the interactive specification begins with @samp{@@}, this means to | ||
| 2727 | select the window under the mouse. This selection takes place before | ||
| 2728 | doing anything else with the command. | ||
| 2729 | |||
| 2730 | You can use both @samp{@@} and @samp{*} together in one command; they | ||
| 2731 | are processed in order of appearance. | ||
| 2732 | |||
| 2733 | @item | ||
| 2734 | Prompts in an interactive specification can incorporate the values of | ||
| 2735 | the preceding arguments. Emacs replaces @samp{%}-sequences (as used | ||
| 2736 | with the @code{format} function) in the prompt with the interactive | ||
| 2737 | arguments that have been read so far. For example, a command with this | ||
| 2738 | interactive specification | ||
| 2739 | |||
| 2740 | @example | ||
| 2741 | (interactive "sReplace: \nsReplace %s with: ") | ||
| 2742 | @end example | ||
| 2743 | |||
| 2744 | @noindent | ||
| 2745 | prompts for the first argument with @samp{Replace: }, and then prompts | ||
| 2746 | for the second argument with @samp{Replace @var{foo} with: }, where | ||
| 2747 | @var{foo} is the string read as the first argument. | ||
| 2748 | |||
| 2749 | @item | ||
| 2750 | If a command name has a property @code{enable-recursive-minibuffers} | ||
| 2751 | which is non-@code{nil}, then the command can use the minibuffer to read | ||
| 2752 | arguments even if it is invoked from the minibuffer. The minibuffer | ||
| 2753 | command @code{next-matching-history-element} (normally bound to | ||
| 2754 | @kbd{M-s} in the minibuffer) uses this feature. | ||
| 2755 | @end itemize | ||
| 2756 | |||
| 2757 | @section New Features for Reading Input | ||
| 2758 | |||
| 2759 | @itemize @bullet | ||
| 2760 | @item | ||
| 2761 | The function @code{set-input-mode} now takes four arguments. The last | ||
| 2762 | argument is optional. Their names are @var{interrupt}, @var{flow}, | ||
| 2763 | @var{meta} and @var{quit}. | ||
| 2764 | |||
| 2765 | The argument @var{interrupt} says whether to use interrupt-driven | ||
| 2766 | input. Non-@code{nil} means yes, and @code{nil} means no (use CBREAK | ||
| 2767 | mode). | ||
| 2768 | |||
| 2769 | The argument @var{flow} says whether to enable terminal flow control. | ||
| 2770 | Non-@code{nil} means yes. | ||
| 2771 | |||
| 2772 | The argument @var{meta} says whether to enable the use of a Meta key. | ||
| 2773 | Non-@code{nil} means yes. | ||
| 2774 | |||
| 2775 | If @var{quit} non-@code{nil}, it is the character to use for quitting. | ||
| 2776 | (Normally this is @kbd{C-g}.) | ||
| 2777 | |||
| 2778 | @item | ||
| 2779 | The variable @code{meta-flag} has been deleted; use | ||
| 2780 | @code{set-input-mode} to enable or disable support for a @key{META} | ||
| 2781 | key. This change was made because @code{set-input-mode} can send the | ||
| 2782 | terminal the appropriate commands to enable or disable operation of the | ||
| 2783 | @key{META} key. | ||
| 2784 | |||
| 2785 | @item | ||
| 2786 | The new variable @code{extra-keyboard-modifiers} lets Lisp programs | ||
| 2787 | ``press'' the modifier keys on the keyboard. | ||
| 2788 | The value is a bit mask: | ||
| 2789 | |||
| 2790 | @table @asis | ||
| 2791 | @item 1 | ||
| 2792 | The @key{SHIFT} key. | ||
| 2793 | @item 2 | ||
| 2794 | The @key{LOCK} key. | ||
| 2795 | @item 4 | ||
| 2796 | The @key{CTL} key. | ||
| 2797 | @item 8 | ||
| 2798 | The @key{META} key. | ||
| 2799 | @end table | ||
| 2800 | |||
| 2801 | When you use X windows, the program can press any of the modifier keys | ||
| 2802 | in this way. Otherwise, only the @key{CTL} and @key{META} keys can be | ||
| 2803 | virtually pressed. | ||
| 2804 | |||
| 2805 | @item | ||
| 2806 | You can use the new function @code{keyboard-translate} to set up | ||
| 2807 | @code{keyboard-translate-table} conveniently. | ||
| 2808 | |||
| 2809 | @item | ||
| 2810 | Y-or-n questions using the @code{y-or-n-p} function now accept @kbd{C-]} | ||
| 2811 | (usually mapped to @code{abort-recursive-edit}) as well as @kbd{C-g} to | ||
| 2812 | quit. | ||
| 2813 | |||
| 2814 | @item | ||
| 2815 | The variable @code{num-input-keys} is the total number of key sequences | ||
| 2816 | that the user has typed during this Emacs session. | ||
| 2817 | |||
| 2818 | @item | ||
| 2819 | A new Lisp variable, @code{function-key-map}, holds a keymap which | ||
| 2820 | describes the character sequences sent by function keys on an ordinary | ||
| 2821 | character terminal. This uses the same keymap data structure that is | ||
| 2822 | used to hold bindings of key sequences, but it has a different meaning: | ||
| 2823 | it specifies translations to make while reading a key sequence. | ||
| 2824 | |||
| 2825 | If @code{function-key-map} ``binds'' a key sequence @var{k} to a vector | ||
| 2826 | @var{v}, then when @var{k} appears as a subsequence @emph{anywhere} in a | ||
| 2827 | key sequence, it is replaced with @var{v}. | ||
| 2828 | |||
| 2829 | For example, VT100 terminals send @kbd{@key{ESC} O P} when the ``keypad'' | ||
| 2830 | PF1 key is pressed. Thus, on a VT100, @code{function-key-map} should | ||
| 2831 | ``bind'' that sequence to @code{[pf1]}. This specifies translation of | ||
| 2832 | @kbd{@key{ESC} O P} into @key{PF1} anywhere in a key sequence. | ||
| 2833 | |||
| 2834 | Thus, typing @kbd{C-c @key{PF1}} sends the character sequence @kbd{C-c | ||
| 2835 | @key{ESC} O P}, but @code{read-key-sequence} translates this back into | ||
| 2836 | @kbd{C-c @key{PF1}}, which it returns as the vector @code{[?\C-c PF1]}. | ||
| 2837 | |||
| 2838 | Entries in @code{function-key-map} are ignored if they conflict with | ||
| 2839 | bindings made in the minor mode, local, or global keymaps. | ||
| 2840 | |||
| 2841 | The value of @code{function-key-map} is usually set up automatically | ||
| 2842 | according to the terminal's Terminfo or Termcap entry, and the | ||
| 2843 | terminal-specific Lisp files. Emacs comes with a number of | ||
| 2844 | terminal-specific files for many common terminals; their main purpose is | ||
| 2845 | to make entries in @code{function-key-map} beyond those that can be | ||
| 2846 | deduced from Termcap and Terminfo. | ||
| 2847 | |||
| 2848 | @item | ||
| 2849 | The variable @code{key-translation-map} works like @code{function-key-map} | ||
| 2850 | except for two things: | ||
| 2851 | |||
| 2852 | @itemize @bullet | ||
| 2853 | @item | ||
| 2854 | @code{key-translation-map} goes to work after @code{function-key-map} is | ||
| 2855 | finished; it receives the results of translation by | ||
| 2856 | @code{function-key-map}. | ||
| 2857 | |||
| 2858 | @item | ||
| 2859 | @code{key-translation-map} overrides actual key bindings. | ||
| 2860 | @end itemize | ||
| 2861 | |||
| 2862 | The intent of @code{key-translation-map} is for users to map one | ||
| 2863 | character set to another, including ordinary characters normally bound | ||
| 2864 | to @code{self-insert-command}. | ||
| 2865 | @end itemize | ||
| 2866 | |||
| 2867 | @section New Syntax Table Features | ||
| 2868 | |||
| 2869 | @itemize @bullet | ||
| 2870 | @item | ||
| 2871 | You can use two new functions to move across characters in certain | ||
| 2872 | syntax classes. | ||
| 2873 | |||
| 2874 | @code{skip-syntax-forward} moves point forward across characters whose | ||
| 2875 | syntax classes are mentioned in its first argument, a string. It stops | ||
| 2876 | when it encounters the end of the buffer, or position @var{lim} (the | ||
| 2877 | optional second argument), or a character it is not supposed to skip. | ||
| 2878 | The function @code{skip-syntax-backward} is similar but moves backward. | ||
| 2879 | |||
| 2880 | @item | ||
| 2881 | The new function @code{forward-comment} moves point by comments. It | ||
| 2882 | takes one argument, @var{count}; it moves point forward across | ||
| 2883 | @var{count} comments (backward, if @var{count} is negative). If it | ||
| 2884 | finds anything other than a comment or whitespace, it stops, leaving | ||
| 2885 | point at the far side of the last comment found. It also stops after | ||
| 2886 | satisfying @var{count}. | ||
| 2887 | |||
| 2888 | @item | ||
| 2889 | The new variable @code{words-include-escapes} affects the behavior of | ||
| 2890 | @code{forward-word} and everything that uses it. If it is | ||
| 2891 | non-@code{nil}, then characters in the ``escape'' and ``character | ||
| 2892 | quote'' syntax classes count as part of words. | ||
| 2893 | |||
| 2894 | @item | ||
| 2895 | There are two new syntax flags for use in syntax tables. | ||
| 2896 | |||
| 2897 | @itemize - | ||
| 2898 | @item | ||
| 2899 | The prefix flag. | ||
| 2900 | |||
| 2901 | The @samp{p} flag identifies additional ``prefix characters'' in Lisp | ||
| 2902 | syntax. You can set this flag with @code{modify-syntax-entry} by | ||
| 2903 | including the letter @samp{p} in the syntax specification. | ||
| 2904 | |||
| 2905 | These characters are treated as whitespace when they appear between | ||
| 2906 | expressions. When they appear withing an expression, they are handled | ||
| 2907 | according to their usual syntax codes. | ||
| 2908 | |||
| 2909 | The function @code{backward-prefix-chars} moves back over these | ||
| 2910 | characters, as well as over characters whose primary syntax class is | ||
| 2911 | prefix (@samp{'}). | ||
| 2912 | |||
| 2913 | @item | ||
| 2914 | The @samp{b} comment style flag. | ||
| 2915 | |||
| 2916 | Emacs can now supports two comment styles simultaneously. (This is for | ||
| 2917 | the sake of C++.) More specifically, it can recognize two different | ||
| 2918 | comment-start sequences. Both must share the same first character; only | ||
| 2919 | the second character may differ. Mark the second character of the | ||
| 2920 | @samp{b}-style comment start sequence with the @samp{b} flag. You can | ||
| 2921 | set this flag with @code{modify-syntax-entry} by including the letter | ||
| 2922 | @samp{b} in the syntax specification. | ||
| 2923 | |||
| 2924 | The two styles of comment can have different comment-end sequences. A | ||
| 2925 | comment-end sequence (one or two characters) applies to the @samp{b} | ||
| 2926 | style if its first character has the @samp{b} flag set; otherwise, it | ||
| 2927 | applies to the @samp{a} style. | ||
| 2928 | |||
| 2929 | The appropriate comment syntax settings for C++ are as follows: | ||
| 2930 | |||
| 2931 | @table @asis | ||
| 2932 | @item @samp{/} | ||
| 2933 | @samp{124b} | ||
| 2934 | @item @samp{*} | ||
| 2935 | @samp{23} | ||
| 2936 | @item newline | ||
| 2937 | @samp{>b} | ||
| 2938 | @end table | ||
| 2939 | |||
| 2940 | Thus @samp{/*} is a comment-start sequence for @samp{a} style, @samp{//} | ||
| 2941 | is a comment-start sequence for @samp{b} style, @samp{*/} is a | ||
| 2942 | comment-end sequence for @samp{a} style, and newline is a comment-end | ||
| 2943 | sequence for @samp{b} style. | ||
| 2944 | @end itemize | ||
| 2945 | @end itemize | ||
| 2946 | |||
| 2947 | @section The Case Table | ||
| 2948 | |||
| 2949 | You can customize case conversion using the new case table feature. A | ||
| 2950 | case table is a collection of strings that specifies the mapping between | ||
| 2951 | upper case and lower case letters. Each buffer has its own case table. | ||
| 2952 | You need a case table if you are using a language which has letters that | ||
| 2953 | are not standard ASCII letters. | ||
| 2954 | |||
| 2955 | A case table is a list of this form: | ||
| 2956 | |||
| 2957 | @example | ||
| 2958 | (@var{downcase} @var{upcase} @var{canonicalize} @var{equivalences}) | ||
| 2959 | @end example | ||
| 2960 | |||
| 2961 | @noindent | ||
| 2962 | where each element is either @code{nil} or a string of length 256. The | ||
| 2963 | element @var{downcase} says how to map each character to its lower-case | ||
| 2964 | equivalent. The element @var{upcase} maps each character to its | ||
| 2965 | upper-case equivalent. If lower and upper case characters are in 1-1 | ||
| 2966 | correspondence, use @code{nil} for @var{upcase}; then Emacs deduces the | ||
| 2967 | upcase table from @var{downcase}. | ||
| 2968 | |||
| 2969 | For some languages, upper and lower case letters are not in 1-1 | ||
| 2970 | correspondence. There may be two different lower case letters with the | ||
| 2971 | same upper case equivalent. In these cases, you need to specify the | ||
| 2972 | maps for both directions. | ||
| 2973 | |||
| 2974 | The element @var{canonicalize} maps each character to a canonical | ||
| 2975 | equivalent; any two characters that are related by case-conversion have | ||
| 2976 | the same canonical equivalent character. | ||
| 2977 | |||
| 2978 | The element @var{equivalences} is a map that cyclicly permutes each | ||
| 2979 | equivalence class (of characters with the same canonical equivalent). | ||
| 2980 | |||
| 2981 | You can provide @code{nil} for both @var{canonicalize} and | ||
| 2982 | @var{equivalences}, in which case both are deduced from @var{downcase} | ||
| 2983 | and @var{upcase}. | ||
| 2984 | |||
| 2985 | Here are the functions for working with case tables: | ||
| 2986 | |||
| 2987 | @code{case-table-p} is a predicate that says whether a Lisp object is a | ||
| 2988 | valid case table. | ||
| 2989 | |||
| 2990 | @code{set-standard-case-table} takes one argument and makes that | ||
| 2991 | argument the case table for new buffers created subsequently. | ||
| 2992 | @code{standard-case-table} returns the current value of the new buffer | ||
| 2993 | case table. | ||
| 2994 | |||
| 2995 | @code{current-case-table} returns the case table of the current buffer. | ||
| 2996 | @code{set-case-table} sets the current buffer's case table to the | ||
| 2997 | argument. | ||
| 2998 | |||
| 2999 | @code{set-case-syntax-pair} is a convenient function for specifying a | ||
| 3000 | pair of letters, upper case and lower case. Call it with two arguments, | ||
| 3001 | the upper case letter and the lower case letter. It modifies the | ||
| 3002 | standard case table and a few syntax tables that are predefined in | ||
| 3003 | Emacs. This function is intended as a subroutine for packages that | ||
| 3004 | define non-ASCII character sets. | ||
| 3005 | |||
| 3006 | Load the library @file{iso-syntax} to set up the syntax and case table for | ||
| 3007 | the 256 bit ISO Latin 1 character set. | ||
| 3008 | |||
| 3009 | @section New Features for Dealing with Buffers | ||
| 3010 | |||
| 3011 | @itemize @bullet | ||
| 3012 | @item | ||
| 3013 | The new function @code{buffer-modified-tick} returns a buffer's | ||
| 3014 | modification-count that ticks every time the buffer is modified. It | ||
| 3015 | takes one optional argument, which is the buffer you want to examine. | ||
| 3016 | If the argument is @code{nil} (or omitted), the current buffer is used. | ||
| 3017 | |||
| 3018 | @item | ||
| 3019 | @code{buffer-disable-undo} is a new name for the function | ||
| 3020 | formerly known as @code{buffer-flush-undo}. This turns off recording | ||
| 3021 | of undo information in the buffer given as argument. | ||
| 3022 | |||
| 3023 | @item | ||
| 3024 | The new function @code{generate-new-buffer-name} chooses a name that | ||
| 3025 | would be unique for a new buffer---but does not create the buffer. Give | ||
| 3026 | it one argument, a starting name. It produces a name not in use for a | ||
| 3027 | buffer by appending a number inside of @samp{<@dots{}>}. | ||
| 3028 | |||
| 3029 | @item | ||
| 3030 | The function @code{rename-buffer} now takes an option second argument | ||
| 3031 | which tells it that if the specified new name corresponds to an existing | ||
| 3032 | buffer, it should use @code{generate-new-buffer-name} to modify the name | ||
| 3033 | to be unique, rather than signaling an error. | ||
| 3034 | |||
| 3035 | @code{rename-buffer} now returns the name to which the buffer was | ||
| 3036 | renamed. | ||
| 3037 | |||
| 3038 | @item | ||
| 3039 | The function @code{list-buffers} now looks at the local variable | ||
| 3040 | @code{list-buffers-directory} in each non-file-visiting buffer, and | ||
| 3041 | shows its value where the file would normally go. Dired sets this | ||
| 3042 | variable in each Dired buffer, so the buffer list now shows which | ||
| 3043 | directory each Dired buffer is editing. | ||
| 3044 | |||
| 3045 | @item | ||
| 3046 | The function @code{other-buffer} now takes an optional second argument | ||
| 3047 | @var{visible-ok} which, if non-@code{nil}, indicates that buffers | ||
| 3048 | currently being displayed in windows may be returned even if there are | ||
| 3049 | other buffers not visible. Normally, @code{other-buffer} returns a | ||
| 3050 | currently visible buffer only as a last resort, if there are no suitable | ||
| 3051 | nonvisible buffers. | ||
| 3052 | |||
| 3053 | @item | ||
| 3054 | The hook @code{kill-buffer-hook} now runs whenever a buffer is killed. | ||
| 3055 | @end itemize | ||
| 3056 | |||
| 3057 | @section Local Variables Features | ||
| 3058 | |||
| 3059 | @itemize @bullet | ||
| 3060 | @item | ||
| 3061 | If a local variable name has a non-@code{nil} @code{permanent-local} | ||
| 3062 | property, then @code{kill-all-local-variables} does not kill it. Such | ||
| 3063 | local variables are ``permanent''---they remain unchanged even if you | ||
| 3064 | select a different major mode. | ||
| 3065 | |||
| 3066 | Permanent locals are useful when they have to do with where the file | ||
| 3067 | came from or how to save it, rather than with how to edit the contents. | ||
| 3068 | |||
| 3069 | @item | ||
| 3070 | The function @code{make-local-variable} now never changes the value of the variable | ||
| 3071 | that it makes local. If the variable had no value before, it still has | ||
| 3072 | no value after becoming local. | ||
| 3073 | |||
| 3074 | @item | ||
| 3075 | The new function @code{default-boundp} tells you whether a variable has | ||
| 3076 | a default value (as opposed to being unbound in its default value). If | ||
| 3077 | @code{(default-boundp 'foo)} returns @code{nil}, then | ||
| 3078 | @code{(default-value 'foo)} would get an error. | ||
| 3079 | |||
| 3080 | @code{default-boundp} is to @code{default-value} as @code{boundp} is to | ||
| 3081 | @code{symbol-value}. | ||
| 3082 | |||
| 3083 | @item | ||
| 3084 | The special forms @code{defconst} and @code{defvar}, when the variable | ||
| 3085 | is local in the current buffer, now set the variable's default value | ||
| 3086 | rather than its local value. | ||
| 3087 | @end itemize | ||
| 3088 | |||
| 3089 | @section New Features for Subprocesses | ||
| 3090 | |||
| 3091 | @itemize @bullet | ||
| 3092 | @item | ||
| 3093 | @code{call-process} and @code{call-process-region} now return a value | ||
| 3094 | that indicates how the synchronous subprocess terminated. It is either | ||
| 3095 | a number, which is the exit status of a process, or a signal name | ||
| 3096 | represented as a string. | ||
| 3097 | |||
| 3098 | @item | ||
| 3099 | @code{process-status} now returns @code{open} and @code{closed} as the | ||
| 3100 | status values for network connections. | ||
| 3101 | |||
| 3102 | @item | ||
| 3103 | The standard asynchronous subprocess features work on VMS now, | ||
| 3104 | and the special VMS asynchronous subprocess functions have been deleted. | ||
| 3105 | |||
| 3106 | @item | ||
| 3107 | You can use the transaction queue feature for more convenient | ||
| 3108 | communication with subprocesses using transactions. | ||
| 3109 | |||
| 3110 | Call @code{tq-create} to create a transaction queue communicating with a | ||
| 3111 | specified process. Then you can call @code{tq-enqueue} to send a | ||
| 3112 | transaction. @code{tq-enqueue} takes these five arguments: | ||
| 3113 | |||
| 3114 | @example | ||
| 3115 | (tq-enqueue @var{tq} @var{question} @var{regexp} @var{closure} @var{fn}) | ||
| 3116 | @end example | ||
| 3117 | |||
| 3118 | @var{tq} is the queue to use. (Specifying the queue has the effect of | ||
| 3119 | specifying the process to talk to.) The argument @var{question} is the | ||
| 3120 | outgoing message which starts the transaction. The argument @var{fn} is | ||
| 3121 | the function to call when the corresponding answer comes back; it is | ||
| 3122 | called with two arguments: @var{closure}, and the answer received. | ||
| 3123 | |||
| 3124 | The argument @var{regexp} is a regular expression to match the entire | ||
| 3125 | answer; that's how @code{tq-enqueue} tells where the answer ends. | ||
| 3126 | |||
| 3127 | Call @code{tq-close} to shut down a transaction queue and terminate its | ||
| 3128 | subprocess. | ||
| 3129 | |||
| 3130 | @item | ||
| 3131 | The function @code{signal-process} sends a signal to process @var{pid}, | ||
| 3132 | which need not be a child of Emacs. The second argument @var{signal} | ||
| 3133 | specifies which signal to send; it should be an integer. | ||
| 3134 | @end itemize | ||
| 3135 | |||
| 3136 | @section New Features for Dealing with Times And Time Delays | ||
| 3137 | |||
| 3138 | @itemize @bullet | ||
| 3139 | @item | ||
| 3140 | The new function @code{current-time} returns the system's time value as | ||
| 3141 | a list of three integers: @code{(@var{high} @var{low} @var{microsec})}. | ||
| 3142 | The integers @var{high} and @var{low} combine to give the number of | ||
| 3143 | seconds since 0:00 January 1, 1970, which is @var{high} * 2**16 + | ||
| 3144 | @var{low}. | ||
| 3145 | |||
| 3146 | @var{microsec} gives the microseconds since the start of the current | ||
| 3147 | second (or 0 for systems that return time only on the resolution of a | ||
| 3148 | second). | ||
| 3149 | |||
| 3150 | @item | ||
| 3151 | The function @code{current-time-string} accepts an optional argument | ||
| 3152 | @var{time-value}. If given, this specifies a time to format instead of | ||
| 3153 | the current time. The argument should be a cons cell containing two | ||
| 3154 | integers, or a list whose first two elements are integers. Thus, you | ||
| 3155 | can use times obtained from @code{current-time} (see above) and from | ||
| 3156 | @code{file-attributes}. | ||
| 3157 | |||
| 3158 | @item | ||
| 3159 | You can now find out the user's time zone using @code{current-time-zone}. | ||
| 3160 | It takes no arguments, and returns a list of this form: | ||
| 3161 | |||
| 3162 | @example | ||
| 3163 | (@var{offset} @var{savings-flag} @var{standard} @var{savings}) | ||
| 3164 | @end example | ||
| 3165 | |||
| 3166 | @var{offset} is an integer specifying how many minutes east of Greenwich | ||
| 3167 | the current time zone is located. A negative value means west of | ||
| 3168 | Greenwich. Note that this describes the standard time; if daylight | ||
| 3169 | savings time is in effect, it does not affect this value. | ||
| 3170 | |||
| 3171 | @var{savings-flag} is non-@code{nil} iff daylight savings time or some other | ||
| 3172 | sort of seasonal time adjustment is in effect. | ||
| 3173 | |||
| 3174 | @var{standard} is a string giving the name of the time zone when no | ||
| 3175 | seasonal time adjustment is in effect. | ||
| 3176 | |||
| 3177 | @var{savings} is a string giving the name of the time zone when there is a | ||
| 3178 | seasonal time adjustment in effect. | ||
| 3179 | |||
| 3180 | If the user has specified a region that does not use a seasonal time | ||
| 3181 | adjustment, @var{savings-flag} is always @code{nil}, and @var{standard} | ||
| 3182 | and @var{savings} are equal. | ||
| 3183 | |||
| 3184 | @item | ||
| 3185 | @code{sit-for}, @code{sleep-for} now let you specify the time period in | ||
| 3186 | milliseconds as well as in seconds. The first argument gives the number | ||
| 3187 | of seconds, as before, and the optional second argument gives additional | ||
| 3188 | milliseconds. The time periods specified by these two arguments are | ||
| 3189 | added together. | ||
| 3190 | |||
| 3191 | Not all systems support this; you get an error if you specify nonzero | ||
| 3192 | milliseconds and it isn't supported. | ||
| 3193 | |||
| 3194 | @code{sit-for} also accepts an optional third argument @var{nodisp}. If | ||
| 3195 | this is non-@code{nil}, @code{sit-for} does not redisplay. It still | ||
| 3196 | waits for the specified time or until input is available. | ||
| 3197 | |||
| 3198 | @item | ||
| 3199 | @code{accept-process-output} now accepts a timeout specified by optional | ||
| 3200 | second and third arguments. The second argument specifies the number of | ||
| 3201 | seconds, while the third specifies the number of milliseconds. The time | ||
| 3202 | periods specified by these two arguments are added together. | ||
| 3203 | |||
| 3204 | Not all systems support this; you get an error if you specify nonzero | ||
| 3205 | milliseconds and it isn't supported. | ||
| 3206 | |||
| 3207 | The function returns @code{nil} if the timeout expired before output | ||
| 3208 | arrived, or non-@code{nil} if it did get some output. | ||
| 3209 | |||
| 3210 | @item | ||
| 3211 | You can set up a timer to call a function at a specified future time. | ||
| 3212 | To do so, call @code{run-at-time}, like this: | ||
| 3213 | |||
| 3214 | @example | ||
| 3215 | (run-at-time @var{time} @var{repeat} @var{function} @var{args}@dots{}) | ||
| 3216 | @end example | ||
| 3217 | |||
| 3218 | Here, @var{time} is a string saying when to call the function. The | ||
| 3219 | argument @var{function} is the function to call later, and @var{args} | ||
| 3220 | are the arguments to give it when it is called. | ||
| 3221 | |||
| 3222 | The argument @var{repeat} specifies how often to repeat the call. If | ||
| 3223 | @var{repeat} is @code{nil}, there are no repetitions; @var{function} is | ||
| 3224 | called just once, at @var{time}. If @var{repeat} is an integer, it | ||
| 3225 | specifies a repetition period measured in seconds. | ||
| 3226 | |||
| 3227 | Absolute times may be specified in a wide variety of formats; The form | ||
| 3228 | @samp{@var{hour}:@var{min}:@var{sec} @var{timezone} | ||
| 3229 | @var{month}/@var{day}/@var{year}}, where all fields are numbers, works; | ||
| 3230 | the format that @code{current-time-string} returns is also allowed. | ||
| 3231 | |||
| 3232 | To specify a relative time, use numbers followed by units. | ||
| 3233 | For example: | ||
| 3234 | |||
| 3235 | @table @samp | ||
| 3236 | @item 1 min | ||
| 3237 | denotes 1 minute from now. | ||
| 3238 | @item 1 min 5 sec | ||
| 3239 | denotes 65 seconds from now. | ||
| 3240 | @item 1 min 2 sec 3 hour 4 day 5 week 6 fortnight 7 month 8 year | ||
| 3241 | denotes exactly 103 months, 123 days, and 10862 seconds from now. | ||
| 3242 | @end table | ||
| 3243 | |||
| 3244 | If @var{time} is an integer, that specifies a relative time measured in | ||
| 3245 | seconds. | ||
| 3246 | @end itemize | ||
| 3247 | |||
| 3248 | To cancel the requested future action, pass the value that @code{run-at-time} | ||
| 3249 | returned to the function @code{cancel-timer}. | ||
| 3250 | |||
| 3251 | @section Profiling Lisp Programs | ||
| 3252 | |||
| 3253 | You can now make execution-time profiles of Emacs Lisp programs using | ||
| 3254 | the @file{profile} library. See the file @file{profile.el} for | ||
| 3255 | instructions; if you have written a Lisp program big enough to be worth | ||
| 3256 | profiling, you can surely understand them. | ||
| 3257 | |||
| 3258 | @section New Features for Lisp Debuggers | ||
| 3259 | |||
| 3260 | @itemize @bullet | ||
| 3261 | @item | ||
| 3262 | You can now specify which kinds of errors should invoke the Lisp | ||
| 3263 | debugger by setting the variable @code{debug-on-error} to a list of error | ||
| 3264 | conditions. For example, if you set it to the list @code{(void-variable)}, | ||
| 3265 | then only errors about a variable that has no value invoke the | ||
| 3266 | debugger. | ||
| 3267 | |||
| 3268 | @item | ||
| 3269 | The variable @code{command-debug-status} is used by Lisp debuggers. It | ||
| 3270 | records the debugging status of current interactive command. Each time | ||
| 3271 | a command is called interactively, this variable is bound to | ||
| 3272 | @code{nil}. The debugger can set this variable to leave information for | ||
| 3273 | future debugger invocations during the same command. | ||
| 3274 | |||
| 3275 | The advantage of this variable over some other variable in the debugger | ||
| 3276 | itself is that the data will not be visible for any other command | ||
| 3277 | invocation. | ||
| 3278 | |||
| 3279 | @item | ||
| 3280 | The function @code{backtrace-frame} is intended for use in Lisp | ||
| 3281 | debuggers. It returns information about what a frame on the Lisp call | ||
| 3282 | stack is doing. You specify one argument, which is the number of stack | ||
| 3283 | frames to count up from the current execution point. | ||
| 3284 | |||
| 3285 | If that stack frame has not evaluated the arguments yet (or is a special | ||
| 3286 | form), the value is @code{(nil @var{function} @var{arg-forms}@dots{})}. | ||
| 3287 | |||
| 3288 | If that stack frame has evaluated its arguments and called its function | ||
| 3289 | already, the value is @code{(t @var{function} | ||
| 3290 | @var{arg-values}@dots{})}. | ||
| 3291 | |||
| 3292 | In the return value, @var{function} is whatever was supplied as @sc{car} | ||
| 3293 | of evaluated list, or a @code{lambda} expression in the case of a macro | ||
| 3294 | call. If the function has a @code{&rest} argument, that is represented | ||
| 3295 | as the tail of the list @var{arg-values}. | ||
| 3296 | |||
| 3297 | If the argument is out of range, @code{backtrace-frame} returns | ||
| 3298 | @code{nil}. | ||
| 3299 | @end itemize | ||
| 3300 | |||
| 3301 | @ignore | ||
| 3302 | |||
| 3303 | @item | ||
| 3304 | @code{kill-ring-save} now gives visual feedback to indicate the region | ||
| 3305 | of text being added to the kill ring. If the opposite end of the | ||
| 3306 | region is visible in the current window, the cursor blinks there. | ||
| 3307 | Otherwise, some text from the other end of the region is displayed in | ||
| 3308 | the message area. | ||
| 3309 | @end ignore | ||
| 3310 | |||
| 3311 | @section Memory Allocation Changes | ||
| 3312 | |||
| 3313 | The list that @code{garbage-collect} returns now has one additional | ||
| 3314 | element. This is a cons cell containing two numbers. It gives | ||
| 3315 | information about the number of used and free floating point numbers, | ||
| 3316 | much as the first element gives such information about the number of | ||
| 3317 | used and free cons cells. | ||
| 3318 | |||
| 3319 | The new function @code{memory-limit} returns an indication of the last | ||
| 3320 | address allocated by Emacs. More precisely, it returns that address | ||
| 3321 | divided by 1024. You can use this to get a general idea of how your | ||
| 3322 | actions affect the memory usage. | ||
| 3323 | |||
| 3324 | @section Hook Changes | ||
| 3325 | |||
| 3326 | @itemize @bullet | ||
| 3327 | @item | ||
| 3328 | Expanding an abbrev first runs the new hook | ||
| 3329 | @code{pre-abbrev-expand-hook}. | ||
| 3330 | |||
| 3331 | @item | ||
| 3332 | The editor command loop runs the normal hook @code{pre-command-hook} | ||
| 3333 | before each command, and runs @code{post-command-hook} after each | ||
| 3334 | command. | ||
| 3335 | |||
| 3336 | @item | ||
| 3337 | Auto-saving runs the new hook @code{auto-save-hook} before actually | ||
| 3338 | starting to save any files. | ||
| 3339 | |||
| 3340 | @item | ||
| 3341 | The new variable @code{revert-buffer-insert-file-contents-function} | ||
| 3342 | holds a function that @code{revert-buffer} now uses to read in the | ||
| 3343 | contents of the reverted buffer---instead of calling | ||
| 3344 | @code{insert-file-contents}. | ||
| 3345 | |||
| 3346 | @item | ||
| 3347 | The variable @code{lisp-indent-hook} has been renamed to | ||
| 3348 | @code{lisp-indent-function}. | ||
| 3349 | |||
| 3350 | @item | ||
| 3351 | The variable @code{auto-fill-hook} has been renamed to | ||
| 3352 | @code{auto-fill-function}. | ||
| 3353 | |||
| 3354 | @item | ||
| 3355 | The variable @code{blink-paren-hook} has been renamed to | ||
| 3356 | @code{blink-paren-function}. | ||
| 3357 | |||
| 3358 | @item | ||
| 3359 | The variable @code{temp-buffer-show-hook} has been renamed to | ||
| 3360 | @code{temp-buffer-show-function}. | ||
| 3361 | |||
| 3362 | @item | ||
| 3363 | The variable @code{suspend-hook} has been renamed to | ||
| 3364 | @code{suspend-hooks}, because it is a list of functions but is not a | ||
| 3365 | normal hook. | ||
| 3366 | |||
| 3367 | @item | ||
| 3368 | The new function @code{add-hook} provides a handy way to add a function | ||
| 3369 | to a hook variable. For example, | ||
| 3370 | |||
| 3371 | @example | ||
| 3372 | (add-hook 'text-mode-hook 'my-text-hook-function) | ||
| 3373 | @end example | ||
| 3374 | |||
| 3375 | @noindent | ||
| 3376 | arranges to call @code{my-text-hook-function} | ||
| 3377 | when entering Text mode or related modes. | ||
| 3378 | @end itemize | ||
| 3379 | |||
| 3380 | @bye | ||