New function ‘char-from-name’

This also fixes the mishandling of "\N{CJK COMPATIBILITY
IDEOGRAPH-F900}", "\N{VARIATION SELECTOR-1}", etc.
Problem reported by Eli Zaretskii in:
http://lists.gnu.org/archive/html/emacs-devel/2016-04/msg00614.html
* doc/lispref/nonascii.texi (Character Codes), etc/NEWS: Document this.
* lisp/international/mule-cmds.el (char-from-name): New function.
(read-char-by-name): Use it.  Document that "BED" is treated as
a name, not as a hexadecimal number.  Reject out-of-range integers,
floating-point numbers, and strings with trailing junk.
* src/lread.c (character_name_to_code): Call char-from-name
instead of inspecting ucs-names directly, so that we handle
computed names like "VARIATION SELECTOR-1".  Do not use an auto
string, since char-from-name might GC.
* test/src/lread-tests.el: Add tests for new behavior, and
fix some old tests that were wrong.

1 files changed, 12 insertions, 0 deletions

diff --git a/doc/lispref/nonascii.texi b/doc/lispref/nonascii.texi
index 0e4aa86e48b..fd2ce3248fd 100644
--- a/doc/lispref/nonascii.texi
+++ b/doc/lispref/nonascii.texi
@@ -420,6 +420,18 @@ codepoint can have.
 @end example
 @end defun
 
+@defun char-from-name string &optional ignore-case
+This function returns the character whose Unicode name is @var{string}.
+If @var{ignore-case} is non-@code{nil}, case is ignored in @var{string}.
+This function returns @code{nil} if @var{string} does not name a character.
+
+@example
+;; U+03A3
+(= (char-from-name "GREEK CAPITAL LETTER SIGMA") #x03A3)
+     @result{} t
+@end example
+@end defun
+
 @defun get-byte &optional pos string
 This function returns the byte at character position @var{pos} in the
 current buffer.  If the current buffer is unibyte, this is literally