On Sunday, October 01, 2000 1:38 AM, Perl6 RFC Librarian
[SMTP:[EMAIL PROTECTED]] wrote:
> This and other RFCs are available on the web at
> http://dev.perl.org/rfc/
>
> =head1 TITLE
>
> Allow multiply matched groups in regexes to return a listref of all matches
>
> =head1 VERSION
>
> Maintainer: Kevin Walker <[EMAIL PROTECTED]>
> Date: 30 Sep 2000
> Mailing List: [EMAIL PROTECTED]
> Number: 360
> Version: 1
> Status: Developing
>
> =head1 DESCRIPTION
>
> Since the October 1 RFC deadline is nigh, this will be pretty informal.
>
> Suppose you want to parse text with looks like:
>
> name: John Abajace
> children: Tom, Dick, Harry
> favorite colors: red, green, blue
>
> name: I. J. Reilly
> children: Jane, Gertrude
> favorite colors: black, white
>
> ...
>
> Currently, this takes two passes:
>
> while ($text =~ /name:\s*(.*?)\n\s*
> children:\s*(.*?)\n\s*
> favorite\ colors:\s*(.*?)\n/sigx) {
> # now second pass for $2 ( = "Tom, Dick, Harry") and $3, yielding
> # list of children and favorite colors
> }
>
> If we introduce a new construction, (?@ ... ), which means "spit out a
> list ref of all matches, not just the last match", then this could be
> done in one pass:
>
> while ($text =~ /name:\s*(.*?)\n\s*
> children:\s*(?:(?@\S+)[, ]*)*\n\s*
> favorite\ colors:\s*(?:(?@\S+)[, ]*)*\n/sigx) {
> # now we have:
> # $1 = "John Abajace";
> # $2 = ["Tom", "Dick", "Harry"]
> # $3 = ["red", "green", "blue"]
> }
>
> Although the above example is contrived, I have very often felt the need
> for this feature in real-world projects.
>
> =head1 IMPLEMENTATION
>
> Unknown.
>
> =head1 REFERENCES
>
> None.
>
>
> --
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Definitely. I think this has been one of the few actual "flaws" in the
language. People are always trying to
($part1, $somevar) =~ s/(.*):(.*)/;
This would be in list context. In scalar context, it could still grab the
number of patterns matched in the parenths, or a 1|0 to indicate a match at
all, which would be less useful. Since it's a common error (I believe it's even
FAQed a few times), the request goes well beyond a request for syntactic sugar,
and points out a flaw in the language. People expect it to be there as a part
of what makes Perl make sense.
