How do I match this without lookbehind?

tedv has asked for the wisdom of the Perl Monks concerning the following question:

Suppose I have a string that matches /^(\~?.)*$/ and I want to split it into each atomic piece that would be matched by (\~?.). How would I code such a regular expression for split? I'd like to use lookbehind, crafting an expression that says, "Split after every non-tilde character", but my O'Reilly Regular Expression book says that perl doesn't support lookbehind. Any suggestions?

-Ted

Originally posted as a Categorized Question.

Comment on How do I match this without lookbehind? Select or Download Code

Replies are listed 'Best First'.
Re: How do I match this without lookbehind? by Adam (Vicar) on Dec 08, 2000 at 05:50 UTC
`my @results = grep {$_} split /([~]*?[^~])/, $input;` [download]	[reply] [d/l]
Re: How do I match this without lookbehind? by chipmunk (Parson) on Dec 08, 2000 at 08:10 UTC
When the Regular Expressions book was published, the latest version of Perl was 5.005_03. As of 5.6.0, Perl does support lookbehind. However, you really don't need lookbehind or split to solve this problem: `@matches = $string =~ /~?./g;`	[reply] [d/l]
Re: How do I match this without lookbehind? by runrig (Abbot) on Dec 08, 2000 at 06:00 UTC
Sometimes split is not the best answer for splitting: `my @results; push @results, $1 while /(~?.)/g;` [download]	[reply] [d/l]
Re: How do I match this without lookbehind? by Shakya (Initiate) on Oct 04, 2007 at 03:31 UTC
`my @results = $string =~ m!([^~]+)!g;` [download]	[reply] [d/l]
Re: How do I match this without lookbehind? by I0 (Priest) on Dec 12, 2000 at 19:26 UTC
Perl v5.6.0 does suport lookbehind `split /(?<=[^~])/` [download] or do you mean `split /(?<=[^~])(?=~)/` Originally posted as a Categorized Answer.	[reply] [d/l] [select]
Re: How do I match this without lookbehind? by I0 (Priest) on Dec 12, 2000 at 19:40 UTC
Perl v5.6.0 does suport lookbehind `split /(?<=[^~])/ #or split /(?<!~)/ #or /(~?.)/g` [download]	[reply] [d/l]
Re: How do I match this without lookbehind? by runrig (Abbot) on Dec 08, 2000 at 06:19 UTC
`my @results; push @results, $1 while /(~?[^~])/g;` [download] Originally posted as a Categorized Answer.	[reply] [d/l]
Re: How do I match this without lookbehind? by Shakya (Initiate) on Oct 03, 2007 at 18:15 UTC
one more - `my @results = $string =~ m!~([^~]+)!g;` [download] Originally posted as a Categorized Answer.	[reply] [d/l]