Boost C++ Libraries: Ticket #589: regex_replace bug

John Maddock — Wed, 22 Mar 2006 10:28:06 GMT

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This is by design, and is compatible with the way Perl does
things: two matches are found, the first matches the "a",
the second matches the zero length string immediately after
the "a".  Therefore two replacements are performed, and
hense the output.  Use .+ instead of .* if you don't want to
find zero length matches.
John Maddock

status changed

John Maddock — Wed, 22 Mar 2006 10:28:07 GMT

status assigned → closed

severity set

coffman@… — Tue, 13 Dec 2011 20:52:30 GMT

severity → Problem

I have found this behavior still exists even when using posix basic or extended regexes. While this behavior may be correct for perl regexes it doesn't seem to be correct for posix basic or extended regexes.

std::string s("a"); const boost::regex e("(.*)", boost::regex::extended); std::string result = boost::regex_replace(s, e, "$&b");

The result is "abb"

If I use gnu's sed utility (GNU sed version 4.1.2) instead I get "ab"

echo a | sed -r "s/(.*)/\1b/g"

and gnu's sed utility claims to use posix extended regex expressions when called with the -r option.

status changed; resolution deleted

coffman@… — Wed, 14 Dec 2011 15:42:19 GMT

status closed → reopened
resolution Invalid

status changed; resolution set

John Maddock — Sat, 07 Jul 2012 18:08:03 GMT

status reopened → closed
resolution → fixed

(In [79339]) Fix regex_iterator and regex_replace to do what grep/sed do for multiple repeats when matching in POSIX mode. Fixes #589.

description changed

John Maddock — Sat, 07 Jul 2012 18:09:08 GMT

description modified (diff)

This is now fixed in Trunk provided match_posix is passed to regex_replace or regex_iterator.

John Maddock — Mon, 16 Jul 2012 08:38:29 GMT

(In [79556]) Merge collected bug fixes from Trunk: Refs #589. Refs #7032. Refs #7084. Refs #6346.