Beefy Boxes and Bandwidth Generously Provided by pair Networks
laziness, impatience, and hubris

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. :-)


Log In?

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

How do I use this? | Other CB clients
Other Users?
Others perusing the Monastery: (8)
As of 2016-10-25 17:47 GMT
Find Nodes?
    Voting Booth?
    How many different varieties (color, size, etc) of socks do you have in your sock drawer?

    Results (326 votes). Check out past polls.