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WARNING merlyn wrote BAD CODE

by Ovid (Cardinal)
on Jul 27, 2000 at 22:55 UTC ( #24729=note: print w/replies, xml ) Need Help??


in reply to RE: Death to Dot Star!
in thread Death to Dot Star!

Okay, the title is kind of a joke. It's just a good-natured tweak at merlyn for the brouhaha over his WARNING t0mas wrote BAD CODE node that generated so much flak. No offense intended :)

merlyn's code was bugging me, but I couldn't quite put my finger on it. My problem was that the dot metacharacter is so indiscriminating that it will match anything. However, I simply assumed that if merlyn posted the code, it must work. His code is great if you're checking for C-style comments that begin and end in something like /* comment here */ or "? comment here ?". But if you read my post, that's not what we were checking for:

    What happens if you were trying to extract questions in quotes without the trailing question mark?
I mentioned embedded question marks (my idea was that we might have more than one question in a quote), but I never mentioned embedded quotes. I just wanted one set of quotes and my original post bears that out. Here's merlyn's code and my correction:
#!/usr/bin/perl -w $myvar = q{ abc"def"g"hi?"jkl }; # This regex is from merlyn print "matched <$1>\n" if $myvar =~ /" # First quote ( # Capture text to $1 (?: # Non-backreferencing parentheses (?!\?") # not question quote? . # ok to inch along )* # Zero or more ) # End capture \?"/sx; # Followed by a question mark and quote # This regex is from Ovid print "matched <$1>\n" if $myvar =~ /" # First quote ( # Capture text to $1 (?: # Non-backreferencing parentheses [^?"] # Not a question mark or parentheses | # or \?(?!") # A question mark not followed by a quote )* # Zero or more ) # End Capture \?"/sx; # Followed by a question mark and quote
The first regex will print matched <def"g"hi>. The second will print matched <hi>.

No disrespect is intended towards Randal as he was right in pointing out that my first regex was broken.

Cheers,
Ovid

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RE: WARNING merlyn wrote BAD CODE
by merlyn (Sage) on Jul 27, 2000 at 22:58 UTC
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