Re: Match a pattern only if it is not within another pattern

[pbeckingham]

Use negative look-behind and negative lookahead.

$str =~ s/((?<!bar)\S*)foo(\S*(?!qux))/${1}123${2}/gx;

Update: Yup - it's broke. Nothing to see here, move along.

[Transient]

That gave me

bl123 and barthis123thatqux and barso123quxhim and123som 123



Update:
However this seems to do what is intended, at least with the test string:


$str =~  s/((?<!bar)\S*)foo((?!\S*qux))/${1}123${2}/gx;

gives

bl123 and barthisfoothatqux and barsofooquxhim and123som 123

[punkish]

sorry, this doesn't work...

$str =~ s/((?<!bar)\S*)foo(\S*(?!qux))/${1}123${2}/gx;

print "$str\n";

prints

bl123 and barthis123thatqux and barso123quxhim and123som 123