@c -*-texinfo-*-
@c This is part of the GNU Emacs Lisp Reference Manual.
-@c Copyright (C) 1990-1995, 1998-1999, 2001-2011
+@c Copyright (C) 1990-1995, 1998-1999, 2001-2012
@c Free Software Foundation, Inc.
@c See the file elisp.texi for copying conditions.
@setfilename ../../info/strings
operate on them with the general array and sequence functions.
(@xref{Sequences Arrays Vectors}.) For example, you can access or
change individual characters in a string using the functions @code{aref}
-and @code{aset} (@pxref{Array Functions}).
+and @code{aset} (@pxref{Array Functions}). However, note that
+@code{length} should @emph{not} be used for computing the width of a
+string on display; use @code{string-width} (@pxref{Width}) instead.
There are two text representations for non-@acronym{ASCII} characters in
Emacs strings (and in buffers): unibyte and multibyte (@pxref{Text
@defun string= string1 string2
This function returns @code{t} if the characters of the two strings
match exactly. Symbols are also allowed as arguments, in which case
-their print names are used.
-Case is always significant, regardless of @code{case-fold-search}.
+the symbol names are used. Case is always significant, regardless of
+@code{case-fold-search}.
+
+This function is equivalent to @code{equal} for comparing two strings
+(@pxref{Equality Predicates}). In particular, the text properties of
+the two strings are ignored. But if either argument is not a string
+or symbol, an error is signaled.
@example
(string= "abc" "abc")
@result{} nil
@end example
-The function @code{string=} ignores the text properties of the two
-strings. When @code{equal} (@pxref{Equality Predicates}) compares two
-strings, it uses @code{string=}.
-
For technical reasons, a unibyte and a multibyte string are
@code{equal} if and only if they contain the same sequence of
character codes and all these codes are either in the range 0 through
@code{string-lessp} is another name for @code{string<}.
@end defun
+@defun string-prefix-p string1 string2 &optional ignore-case
+This function returns non-@code{nil} if @var{string1} is a prefix of
+@var{string2}; i.e., if @var{string2} starts with @var{string1}. If
+the optional argument @var{ignore-case} is non-@code{nil}, the
+comparison ignores case differences.
+@end defun
+
@defun compare-strings string1 start1 end1 string2 start2 end2 &optional ignore-case
This function compares the specified part of @var{string1} with the
specified part of @var{string2}. The specified part of @var{string1}
@example
@group
-(format "The word `%7s' actually has %d letters in it."
+(format "The word `%7s' has %d letters in it."
"foo" (length "foo"))
- @result{} "The word ` foo' actually has 3 letters in it."
-(format "The word `%7s' actually has %d letters in it."
+ @result{} "The word ` foo' has 3 letters in it."
+(format "The word `%7s' has %d letters in it."
"specification" (length "specification"))
- @result{} "The word `specification' actually has 13 letters in it."
+ @result{} "The word `specification' has 13 letters in it."
@end group
@end example
the @samp{#} flag means include a decimal point even if the precision
is zero.
+ The flag @samp{0} ensures that the padding consists of @samp{0}
+characters instead of spaces. This flag is ignored for non-numerical
+specification characters like @samp{%s}, @samp{%S} and @samp{%c}.
+These specification characters accept the @samp{0} flag, but still pad
+with @emph{spaces}.
+
The flag @samp{-} causes the padding inserted by the width
specifier, if any, to be inserted on the right rather than the left.
-The flag @samp{0} ensures that the padding consists of @samp{0}
-characters instead of spaces, inserted on the left. These flags are
-ignored for specification characters for which they do not make sense:
-@samp{%s}, @samp{%S} and @samp{%c} accept the @samp{0} flag, but still
-pad with @emph{spaces} on the left. If both @samp{-} and @samp{0} are
-present and valid, @samp{-} takes precedence.
+If both @samp{-} and @samp{0} are present, the @samp{0} flag is
+ignored.
@example
@group
@acronym{ASCII} characters; for example, in the Turkish language
environment, the @acronym{ASCII} character @samp{I} is downcased into
a Turkish ``dotless i''. This can interfere with code that requires
-ordinary ASCII case conversion, such as implementations of
+ordinary @acronym{ASCII} case conversion, such as implementations of
@acronym{ASCII}-based network protocols. In that case, use the
@code{with-case-table} macro with the variable @var{ascii-case-table},
which stores the unmodified case table for the @acronym{ASCII}
HCoop / bpt / emacs.git / blobdiff