regex matching problem

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

i inherited a file-parser that *seems* to be broken. (ah, the wonders of a new job.)

i reduced the regex-matching to a minimal test script and commented the regex. it works in the test script but not in the real one.

here's the test case:

my $string = '  5954 Bluebonnet Sun Catcher Horizontal Oval 6"X9"     
+1 @ $   39.95 =  $      39.95 ';
my $string2 = '5422  Texas Home Luggage Tag                 6 @ $    3
+.95 = $      23.70';
                                                                      
+                                                                     
+                                                                     
+                                                                     
+                                                                     
+                                                                     
+                                                                     
+  
print " 1 set to $1\n match \n\n" if ( $string2 =~ 
   /([\d]+)  # match first digits ( greedy )
   \s+       # multiple space
   ([\w\s|"|\-|\']+) # capture at word boundary
   \s{2,}     # single space followed by multiple spaces
   ([\d,\.]+) # capture digit, comma, period
   \s\D+      # single space, non-digit character
   ([\d,\.]+)      # capture digit comma period
   \s\D+        # space plus non-digit character
   ([\d,\.]+)      # capture digit comma period
   /ix             # end regex
   ) ;
[download]

and that *works*! when i apply the same regex in the real script ( cut-n-paste between windows) it fails to match. the only differences:
1. no $string. it matches against $_
2. no if. it just matches, then pushes assignments into an array. basically:

my $prodID = $1;
my $prodDescr = $2;
[download]

etc.

i've been banging my head on this and getting nowhere FAST. i've looked for hidden chars in the real file ( vi's 'set list' mode ) and found no differences. any clues as to where i should be looking?

added some cleanup. thx Roy Johnson

Comment on regex matching problem Select or Download Code

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Re: regex matching problem by Roy Johnson (Monsignor) on Jan 20, 2004 at 17:47 UTC
There are some expression-comment disagreements to fix and improvements to make: `/([\d]+) # match first nonspace ( greedy )` [download] No, that's matching digits. `([\w\s\|"\|\-\|\']+) # capture at word boundary` [download] This is a mess, not a word boundary. You want it to be followed by spaces and digits, which it matches, so it's going to backtrack from the $ or @, so you could do `([^@\$]+)` (update: backslashed $). `\s\s+ # single space followed by multiple spaces` [download] Should be written `\s{2,}`, but ok. `([\d,\.]+) # capture digit, comma, period` [download] Any number of them, in any order. `\s[^\d]+ # single space, non-digit character` [download] correct, but better as `\s\D+` Are the strings you're using in your test case the same strings that fail in the actual program? The PerlMonk `tr///` Advocate	[reply] [d/l] [select]
Re: Re: regex matching problem by geektron (Curate) on Jan 20, 2004 at 18:01 UTC
ok, i guess my comments aren't all proper. :-( the original one was whitespaces ... the strings, at least on STDOUT, are identical. i just tossed in this in the 'real' parser: `my $string2 = '5422 Texas Home Luggage Tag 6 @ $ 3 +.95 = $ 23.70'; print "identical strings \n" if $_ eq $string2;` [download] and it did, in fact, print "identical strings".	[reply] [d/l]
Re: Re: regex matching problem by geektron (Curate) on Jan 20, 2004 at 18:19 UTC
("\|\-\|\'+) # capture at word boundary This is a mess, not a word boundary. You want it to be followed by spaces and digits, which it matches, so it's going to backtrack from the $ or @, so you could do (^@$+). actually, that mess seems to be necessary. chaning it to your suggestion breaks the matching. $1 should be set to '5422' in the test string.	[reply]
Re^3: regex matching problem by Roy Johnson (Monsignor) on Jan 20, 2004 at 19:00 UTC
The $ needs to be backslashed, so it isn't parsed as a variable. Then it works. I didn't expect variable interpolation in a character class. Oops. The PerlMonk `tr///` Advocate	[reply]
Re: Re^3: regex matching problem by geektron (Curate) on Jan 20, 2004 at 21:17 UTC
Re: regex matching problem by ysth (Canon) on Jan 20, 2004 at 18:16 UTC
That regex obviously has some problems (e.g. useless repetition of \| characters in a character class) but I'm suspecting a logic error in the "real script" you aren't showing us. Can we see the code that doesn't work to compare to the code you show that you say does work?	[reply]
Re: Re: regex matching problem by geektron (Curate) on Jan 20, 2004 at 18:32 UTC
i feel like a .... i found the problem while trying to throw the stuff into my scratchpad. grrr. after applying some of [id:///300037]'s changes, i forgot to add something. my testcase had: `\s\D+` my realcase had: `\s\D` i know there are probably other issues w/ the regex, but for now, it works .... :-\	[reply] [d/l] [select]
Re: regex matching problem by Theo (Priest) on Jan 20, 2004 at 18:25 UTC
Hi, geektron. You don't mention what kind of failure you're getting, and we don't see the code around your 'real script', so this is a shot in the dark. It may be that something else is tromping on either $_ or, IMO more likely, the $1, $2 etc, variables with other matches after your regex. -Theo- (so many nodes and so little time ... )	[reply]