diff options
Diffstat (limited to 'doc/lispref/strings.texi')
| -rw-r--r-- | doc/lispref/strings.texi | 27 |
1 files changed, 21 insertions, 6 deletions
diff --git a/doc/lispref/strings.texi b/doc/lispref/strings.texi index addf195fad2..374381e5955 100644 --- a/doc/lispref/strings.texi +++ b/doc/lispref/strings.texi @@ -560,6 +560,12 @@ Representations}. @code{string-equal} is another name for @code{string=}. @end defun +@defun string-equal-ignore-case string1 string2 +@code{string-equal-ignore-case} compares strings ignoring case +differences, like @code{char-equal} when @code{case-fold-search} is +@code{t}. +@end defun + @cindex locale-dependent string equivalence @defun string-collate-equalp string1 string2 &optional locale ignore-case This function returns @code{t} if @var{string1} and @var{string2} are @@ -567,11 +573,19 @@ equal with respect to collation rules. A collation rule is not only determined by the lexicographic order of the characters contained in @var{string1} and @var{string2}, but also further rules about relations between these characters. Usually, it is defined by the -@var{locale} environment Emacs is running with. - -For example, characters with different coding points but -the same meaning might be considered as equal, like different grave -accent Unicode characters: +@var{locale} environment Emacs is running with and by the Standard C +library against which Emacs was linked@footnote{ +For more information about collation rules and their locale +dependencies, see @uref{https://unicode.org/reports/tr10/, The Unicode +Collation Algorithm}. Some Standard C libraries, such as the +@acronym{GNU} C Library (a.k.a.@: @dfn{glibc}) implement large +portions of the Unicode Collation Algorithm and use the associated +locale data, Common Locale Data Repository, or @acronym{CLDR}. +}. + +For example, characters with different code points but the same +meaning, like different grave accent Unicode characters, might, in +some locales, be considered as equal: @example @group @@ -759,7 +773,8 @@ The strings are compared by the numeric values of their characters. For instance, @var{str1} is considered less than @var{str2} if its first differing character has a smaller numeric value. If @var{ignore-case} is non-@code{nil}, characters are converted to -upper-case before comparing them. Unibyte strings are converted to +upper-case, using the current buffer's case-table (@pxref{Case +Tables}), before comparing them. Unibyte strings are converted to multibyte for comparison (@pxref{Text Representations}), so that a unibyte string and its conversion to multibyte are always regarded as equal. |