GNU bug report logs -
#12665
regexp fault for closing square bracket within character class
Previous Next
Full log
Message #10 received at 12665-done <at> debbugs.gnu.org (full text, mbox):
Panicz Maciej Godek <godek.maciek <at> gmail.com> writes:
> guile 2.0.5-deb+1-1
> (string-match "[\\[]" "[")
> ===> #("[" (0 . 1))
> (string-match "[\\]]" "]")
> ===> #f
As documented in "Syntax of Regular Expressions" of the Emacs manual
(to which section 6.15 of the Guile manual refers):
To include a `]' in a character set, you must make it the first
character. For example, `[]a]' matches `]' or `a'. To include a
`-', write `-' as the first or last character of the set, or put
it after a range. Thus, `[]-]' matches both `]' and `-'.
For example:
(string-match "[]\\]" "]") ==> #("]" (0 . 1))
Note that backslash is also a member of this character class, and of the
character class in your first example:
(string-match "[]\\]" "\\") ==> #("\\" (0 . 1))
(string-match "[\\[]" "\\") ==> #("\\" (0 . 1))
You might have been thinking that the backslash would escape the square
brackets in your class, but that's not how it works within character
classes. '[' can be included anywhere in a character class without
being escaped, and ']' and '-' are handled as described above.
Regards,
Mark
This bug report was last modified 12 years and 270 days ago.
Previous Next
GNU bug tracking system
Copyright (C) 1999 Darren O. Benham,
1997,2003 nCipher Corporation Ltd,
1994-97 Ian Jackson.