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| author | Dave Love | 2002-05-13 17:50:19 +0000 |
|---|---|---|
| committer | Dave Love | 2002-05-13 17:50:19 +0000 |
| commit | 5bad079652a9590572abce7676f6c43379b883d0 (patch) | |
| tree | f08fed8a8958fe8f65a8db903638ab90f2dbc3f8 /src/coding.c | |
| parent | b2b3bb62eac2eb65ba9e7a429db253349fd441d5 (diff) | |
| download | emacs-5bad079652a9590572abce7676f6c43379b883d0.tar.gz emacs-5bad079652a9590572abce7676f6c43379b883d0.zip | |
Doc fixes.
(Fdefine_coding_system_alias): Use names, not symbols, in
coding-system-alist.
Diffstat (limited to 'src/coding.c')
| -rw-r--r-- | src/coding.c | 27 |
1 files changed, 14 insertions, 13 deletions
diff --git a/src/coding.c b/src/coding.c index 375839fb2bc..8381284fc98 100644 --- a/src/coding.c +++ b/src/coding.c | |||
| @@ -46,8 +46,8 @@ Boston, MA 02111-1307, USA. */ | |||
| 46 | 46 | ||
| 47 | CODING SYSTEM | 47 | CODING SYSTEM |
| 48 | 48 | ||
| 49 | Coding system is an object for a encoding mechanism that contains | 49 | A coding system is an object for an encoding mechanism that contains |
| 50 | information about how to convert byte sequence to character | 50 | information about how to convert byte sequences to character |
| 51 | sequences and vice versa. When we say "decode", it means converting | 51 | sequences and vice versa. When we say "decode", it means converting |
| 52 | a byte sequence of a specific coding system into a character | 52 | a byte sequence of a specific coding system into a character |
| 53 | sequence that is represented by Emacs' internal coding system | 53 | sequence that is represented by Emacs' internal coding system |
| @@ -57,12 +57,12 @@ CODING SYSTEM | |||
| 57 | 57 | ||
| 58 | In Emacs Lisp, a coding system is represented by a Lisp symbol. In | 58 | In Emacs Lisp, a coding system is represented by a Lisp symbol. In |
| 59 | C level, a coding system is represented by a vector of attributes | 59 | C level, a coding system is represented by a vector of attributes |
| 60 | stored in the hash table Vcharset_hash_table. The conversion from a | 60 | stored in the hash table Vcharset_hash_table. The conversion from |
| 61 | coding system symbol to attributes vector is done by looking up | 61 | coding system symbol to attributes vector is done by looking up |
| 62 | Vcharset_hash_table by the symbol. | 62 | Vcharset_hash_table by the symbol. |
| 63 | 63 | ||
| 64 | Coding systems are classified into the following types depending on | 64 | Coding systems are classified into the following types depending on |
| 65 | the mechanism of encoding. Here's a brief descrition about type. | 65 | the encoding mechanism. Here's a brief description of the types. |
| 66 | 66 | ||
| 67 | o UTF-8 | 67 | o UTF-8 |
| 68 | 68 | ||
| @@ -71,12 +71,12 @@ CODING SYSTEM | |||
| 71 | o Charset-base coding system | 71 | o Charset-base coding system |
| 72 | 72 | ||
| 73 | A coding system defined by one or more (coded) character sets. | 73 | A coding system defined by one or more (coded) character sets. |
| 74 | Decoding and encoding are done by code converter defined for each | 74 | Decoding and encoding are done by a code converter defined for each |
| 75 | character set. | 75 | character set. |
| 76 | 76 | ||
| 77 | o Old Emacs' internal format (emacs-mule) | 77 | o Old Emacs internal format (emacs-mule) |
| 78 | 78 | ||
| 79 | The coding system adopted by an old versions of Emacs (20 and 21). | 79 | The coding system adopted by old versions of Emacs (20 and 21). |
| 80 | 80 | ||
| 81 | o ISO2022-base coding system | 81 | o ISO2022-base coding system |
| 82 | 82 | ||
| @@ -101,7 +101,7 @@ CODING SYSTEM | |||
| 101 | 101 | ||
| 102 | o CCL | 102 | o CCL |
| 103 | 103 | ||
| 104 | If a user wants to decode/encode a text encoded in a coding system | 104 | If a user wants to decode/encode text encoded in a coding system |
| 105 | not listed above, he can supply a decoder and an encoder for it in | 105 | not listed above, he can supply a decoder and an encoder for it in |
| 106 | CCL (Code Conversion Language) programs. Emacs executes the CCL | 106 | CCL (Code Conversion Language) programs. Emacs executes the CCL |
| 107 | program while decoding/encoding. | 107 | program while decoding/encoding. |
| @@ -109,7 +109,7 @@ CODING SYSTEM | |||
| 109 | o Raw-text | 109 | o Raw-text |
| 110 | 110 | ||
| 111 | A coding system for a text containing raw eight-bit data. Emacs | 111 | A coding system for a text containing raw eight-bit data. Emacs |
| 112 | treat each byte of source text as a character (except for | 112 | treats each byte of source text as a character (except for |
| 113 | end-of-line conversion). | 113 | end-of-line conversion). |
| 114 | 114 | ||
| 115 | o No-conversion | 115 | o No-conversion |
| @@ -119,13 +119,13 @@ CODING SYSTEM | |||
| 119 | 119 | ||
| 120 | END-OF-LINE FORMAT | 120 | END-OF-LINE FORMAT |
| 121 | 121 | ||
| 122 | How end-of-line of a text is encoded depends on a system. For | 122 | How text end-of-line is encoded depends on operating system. For |
| 123 | instance, Unix's format is just one byte of LF (line-feed) code, | 123 | instance, Unix's format is just one byte of LF (line-feed) code, |
| 124 | whereas DOS's format is two-byte sequence of `carriage-return' and | 124 | whereas DOS's format is two-byte sequence of `carriage-return' and |
| 125 | `line-feed' codes. MacOS's format is usually one byte of | 125 | `line-feed' codes. MacOS's format is usually one byte of |
| 126 | `carriage-return'. | 126 | `carriage-return'. |
| 127 | 127 | ||
| 128 | Since text characters encoding and end-of-line encoding are | 128 | Since text character encoding and end-of-line encoding are |
| 129 | independent, any coding system described above can take any format | 129 | independent, any coding system described above can take any format |
| 130 | of end-of-line (except for no-conversion). | 130 | of end-of-line (except for no-conversion). |
| 131 | 131 | ||
| @@ -134,7 +134,7 @@ STRUCT CODING_SYSTEM | |||
| 134 | Before using a coding system for code conversion (i.e. decoding and | 134 | Before using a coding system for code conversion (i.e. decoding and |
| 135 | encoding), we setup a structure of type `struct coding_system'. | 135 | encoding), we setup a structure of type `struct coding_system'. |
| 136 | This structure keeps various information about a specific code | 136 | This structure keeps various information about a specific code |
| 137 | conversion (e.g. the location of source and destination data). | 137 | conversion (e.g. the location of source and destination data). |
| 138 | 138 | ||
| 139 | */ | 139 | */ |
| 140 | 140 | ||
| @@ -7628,7 +7628,8 @@ DEFUN ("define-coding-system-alias", Fdefine_coding_system_alias, | |||
| 7628 | } | 7628 | } |
| 7629 | 7629 | ||
| 7630 | Fputhash (alias, spec, Vcoding_system_hash_table); | 7630 | Fputhash (alias, spec, Vcoding_system_hash_table); |
| 7631 | Vcoding_system_alist = Fcons (Fcons (alias, Qnil), Vcoding_system_alist); | 7631 | Vcoding_system_alist = Fcons (Fcons (Fsymbol_name (alias), Qnil), |
| 7632 | Vcoding_system_alist); | ||
| 7632 | 7633 | ||
| 7633 | return Qnil; | 7634 | return Qnil; |
| 7634 | } | 7635 | } |