What does it mean Nested quantifiers in regex

Hie everyone,

My perl script gave me the error below when executed

begining of the execution was ok as script was running fine with below verbose

230000 ==> took 44 seconds

235000 ==> took 41 seconds

240000 ==> took 43 seconds

245000 ==> took 42 seconds

Suddenly the script stop running after the last line above and generated below error

Nested quantifiers in regex; marked by <-- HERE in m/^de.e++ <-- HERE issues@dell.com$/ at ./crestbycountry.pl line 420, <DATA> line 1063.

Do you have any idea what we can do to rectify this one here?

Do i have to post my perl script in here for you guys to help me?

The script has 906 lines :)

Thank you Guys

Comment on What does it mean Nested quantifiers in regex
Re: What does it mean Nested quantifiers in regex by jwkrahn (Prior) on Aug 24, 2010 at 01:46 UTC
`+` in the regular expression says to match the previous character (in your case the character `e` ) one or more times, but you can't have another modifier at the end of that modifier.	[reply] [d/l] [select]
Re^2: What does it mean Nested quantifiers in regex by AnomalousMonk (Prior) on Aug 24, 2010 at 04:11 UTC
A regex quantifier combination like `++` is illegal in Perl 5.8, but is supported in 5.10 et seq. See discussion of 'possessive' quantifiers in Quantifiers section of perlre (for 5.10++ of course).	[reply] [d/l]
Re: What does it mean Nested quantifiers in regex by toolic (Chancellor) on Aug 24, 2010 at 02:02 UTC
Do i have to post my perl script in here for you guys to help me? The script has 906 lines :) No, you should not post 906 lines of code. You should get into the habit of isolating your problem to as few lines as possible. In this case, a single line can reproduce the problem. jwkrahn has pointed out your problem, but you can sometimes get more help using diagnostics: `use diagnostics; m/^de.e++issues@dell.com$/; __END__ Nested quantifiers in regex; marked by <-- HERE in m/^de.e++ <-- HERE issues.com$/ at C:\Perl\toolic\foo.pl line 2 (#3) (F) You can't quantify a quantifier without intervening parenthese +s. So things like ** or +* or ?* are illegal. The <-- HERE shows in the +regular expression about where the problem was discovered. Note that the minimal matching quantifiers, *?, +?, and ?? appear to be nested quantifiers, but aren't. See perlre.` [download]	[reply] [d/l]
Re: What does it mean Nested quantifiers in regex by jethro (Monsignor) on Aug 24, 2010 at 02:19 UTC
Another hint: If you don't want to have these '+' as quantifiers and instead want to match plus signs literally, change them to `\+\+`	[reply] [d/l]
Re^2: What does it mean Nested quantifiers in regex by salva (Monsignor) on Aug 24, 2010 at 06:40 UTC
... and the `quotemeta` operator can also help when interpolating variables that may contain special characters into regular expressions.	[reply] [d/l]
Re^2: What does it mean Nested quantifiers in regex by anakin30 (Acolyte) on Aug 24, 2010 at 07:05 UTC
So if i changed the (m/^de.e++ ) plus sign to \+\+ it can work is it?	[reply]
Re^3: What does it mean Nested quantifiers in regex by jethro (Monsignor) on Aug 24, 2010 at 10:02 UTC
Yes, but it depends on what you want to parse with that regex. If you want to parse exactly the string "de.c++issues", then you need the regex `de\.c\+\+issues`. Note that I also escaped the '.' as that is a special char in regexes as well. (Escaping is the method of removing the specialness of special characters by putting a '\' in front of them) Or as salva propossed, you could write `\Qde.c++issues\E`, that would automatically escape all special characters between \Q and \E. This is probably the better way as you don't seem to know much abouts regexes and there are a lot more special characters	[reply] [d/l] [select]


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What does it mean Nested quantifiers in regex

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