Carl-Joseph has asked for the wisdom of the Perl Monks concerning the following question:
On page 72, the book Effective Perl Programming shows some code to remove C-style comments from a string. I've reproduced the code below.
local $_; $_ = " This_Is_Code = 0; /* This is a comment */ /* * Can it handle a mult-line comment, i.e. * one that goes on for more that one * line? Yes, it can. */ This_Is_Code++; "; for (split m!("(:?\\\W|.)*?"|/\*|\*/)!) { if ($in_comment) { $in_comment = 0 if $_ eq "*/" } else { if ( $_ eq "/*" ) { $in_comment = 1; print " "; } else { print; } } }
I have a question about the regular expression that's used in the call to split(). The expression (:?\\\W|.) seems to say match either a non-word character, or any character. Why have both patterns in the alternation when the dot includes non-word characters?
Thanks,
Carl-Joseph
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Replies are listed 'Best First'. | |
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Re: Alternation in Effective Perl Programming Example
by chromatic (Archbishop) on Dec 07, 2000 at 09:03 UTC | |
by a (Friar) on Dec 07, 2000 at 09:43 UTC | |
by a (Friar) on Dec 07, 2000 at 21:50 UTC |
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