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Richard M. Stallman 2000-02-20 14:31:40 +00:00
parent 65d0110b85
commit 2d06696fdc
2 changed files with 43 additions and 5 deletions
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41
lispref/searching.texi
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@ -477,6 +477,25 @@ Full backtracking capability exists to handle multiple uses of
@samp{\|}, if you use the POSIX regular expression functions
(@pxref{POSIX Regexps}).
@item \@{@var{m}\@}
is a postfix operator that repeats the previous pattern exactly @var{m}
times. Thus, @samp{x\@{5\@}} matches the string @samp{xxxxx}
and nothing else. @samp{c[ad]\@{3\@}r} matches string such as
@samp{caaar}, @samp{cdddr}, @samp{cadar}, and so on.
@item \@{@var{m},@var{n}\@}
is more general postfix operator that specifies repetition with a
minimum of @var{m} repeats and a maximum of @var{n} repeats. If @var{m}
is omitted, the minimum is 0; if @var{n} is omitted, there is no
maximum.
For example, @samp{c[ad]\@{1,2\@}r} matches the strings @samp{car},
@samp{cdr}, @samp{caar}, @samp{cadr}, @samp{cdar}, and @samp{cddr}, and
nothing else.@*
@samp{\@{0,1\@}} or @samp{\@{,1\@}} is equivalent to @samp{?}. @*
@samp{\@{0,\@}} or @samp{\@{,\@}} is equivalent to @samp{*}. @*
@samp{\@{1,\@}} is equivalent to @samp{+}.
@item \( @dots{} \)
@cindex @samp{(} in regexp
@cindex @samp{)} in regexp
@ -496,14 +515,26 @@ To enclose a complicated expression for the postfix operators @samp{*},
number (zero or more) of @samp{na} strings.
@item
To record a matched substring for future reference.
To record a matched substring for future reference with
@samp{\@var{digit}} (see below).
@end enumerate
This last application is not a consequence of the idea of a
parenthetical grouping; it is a separate feature that happens to be
assigned as a second meaning to the same @samp{\( @dots{} \)} construct
because there is no conflict in practice between the two meanings.
Here is an explanation of this feature:
parenthetical grouping; it is a separate feature that was assigned as a
second meaning to the same @samp{\( @dots{} \)} construct because, in
pratice, there was usually no conflict between the two meanings. But
occasionally there is a conflict, and that led to the introduction of
shy groups.
@item \(?: @dots{} \)
is the @dfn{shy group} construct. A shy group serves the first two
purposes of an ordinary group (controlling the nesting of other
operators), but it does not get a number, so you cannot refer back to
its value with @samp{\@var{digit}}.
Shy groups are particulary useful for mechanically-constructed regular
expressions because they can be added automatically without altering the
numbering of any ordinary, non-shy groups.
@item \@var{digit}
matches the same text that matched the @var{digit}th occurrence of a

7
src/ChangeLog
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@ -1,3 +1,10 @@
2000-02-20 Richard M. Stallman <rms@caffeine.ai.mit.edu>
* data.c (Fmake_variable_buffer_local): Doc fix.
Init found_for_buffer to 0.
(Fmake_variable_frame_local): If the variable has already
been buffer-local, set the check_frame field.
2000-02-20 Eli Zaretskii <eliz@is.elta.co.il>
* msdos.c (IT_write_glyphs): Allocate a larger screen_buf as data