Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl: the Markov chain saw
 
PerlMonks  

Re^3: Perl Complains of Nested Quantifiers

by demerphq (Chancellor)
on May 22, 2012 at 21:38 UTC ( #971886=note: print w/ replies, xml ) Need Help??


in reply to Re^2: Perl Complains of Nested Quantifiers
in thread Perl Complains of Nested Quantifiers

Well, what this means is that a pattern like /foo(?:baz)++baz/ will never match. If you had a string like "foobazbazbaz" it would fail because (?:baz)++ will "gobble up" all of the "baz" in the string, and then refuse to give anything back. What it means by "does not disable backtracking" is that "foobazbazbaz foobazbazbaz" will *attempt* the /(?:baz)++/ twice, once after each "foo". Neither will match of course, and if the RE was _really_ smart it would know it could never match and wouldn't try at all, but it isn't. :-)

---
$world=~s/war/peace/g


Comment on Re^3: Perl Complains of Nested Quantifiers
Download Code

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://971886]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others scrutinizing the Monastery: (7)
As of 2014-09-20 16:43 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    How do you remember the number of days in each month?











    Results (160 votes), past polls