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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/lispref/nonascii.texi | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/doc/lispref/nonascii.texi b/doc/lispref/nonascii.texi index f495910fcd6..d7d25dc36af 100644 --- a/doc/lispref/nonascii.texi +++ b/doc/lispref/nonascii.texi @@ -855,15 +855,24 @@ function to all or part of the characters in a charset: Call @var{function} for characters in @var{charset}. @var{function} is called with two arguments. The first one is a cons cell @code{(@var{from} . @var{to})}, where @var{from} and @var{to} -indicate a range of characters contained in charset. The second -argument passed to @var{function} is @var{arg}. +indicate a range of characters contained in @var{charset}. The second +argument passed to @var{function} is @var{arg}, or @code{nil} if +@var{arg} is omitted. By default, the range of codepoints passed to @var{function} includes all the characters in @var{charset}, but optional arguments @var{from-code} and @var{to-code} limit that to the range of characters between these two codepoints of @var{charset}. If either of them is @code{nil}, it defaults to the first or last codepoint of -@var{charset}, respectively. +@var{charset}, respectively. Note that @var{from-code} and +@var{to-code} are @var{charset}'s codepoints, not the Emacs codes of +characters; by contrast, the values @var{from} and @var{to} in the +cons cell passed to @var{function} @emph{are} Emacs character codes. +Those Emacs character codes are either Unicode code points, or Emacs +internal code points that extend Unicode and are beyond the Unicode +range of characters @code{0..#x10FFFF} (@pxref{Text Representations}). +The latter happens rarely, with legacy CJK charsets for codepoints of +@var{charset} which specify characters not yet unified with Unicode. @end defun @node Scanning Charsets |