Beefy Boxes and Bandwidth Generously Provided by pair Networks
P is for Practical
 
PerlMonks  

Re^3: ${^MATCH} regex special variable(s) and /p regex modifier

by JavaFan (Canon)
on Oct 04, 2011 at 11:15 UTC ( #929512=note: print w/ replies, xml ) Need Help??


in reply to Re^2: ${^MATCH} regex special variable(s) and /p regex modifier
in thread ${^MATCH} regex special variable(s) and /p regex modifier

With 5.12.2:

$ perl -wE 'my $s = "foo bar"; $s =~ /(bar)/; say ${^PREMATCH}' foo $ perl -wE 'my $s = "foo bar"; $s =~ /bar/; say ${^PREMATCH}' Use of uninitialized value $^PREMATCH in say at -e line 1. $
Note also the difference in what's going on:
$ perl -Mre=debug -wE 'my $s = "foo bar"; $s =~ /bar/;' Compiling REx "bar" Final program: 1: EXACT <bar> (3) 3: END (0) anchored "bar" at 0 (checking anchored isall) minlen 3 Guessing start of match in sv for REx "bar" against "foo bar" Found anchored substr "bar" at offset 4... Starting position does not contradict /^/m... Guessed: match at offset 4 Freeing REx: "bar" $ perl -Mre=debug -wE 'my $s = "foo bar"; $s =~ /(bar)/;' Compiling REx "(bar)" Final program: 1: OPEN1 (3) 3: EXACT <bar> (5) 5: CLOSE1 (7) 7: END (0) anchored "bar" at 0 (checking anchored) minlen 3 Guessing start of match in sv for REx "(bar)" against "foo bar" Found anchored substr "bar" at offset 4... Starting position does not contradict /^/m... Guessed: match at offset 4 Matching REx "(bar)" against "bar" 4 <foo > <bar> | 1:OPEN1(3) 4 <foo > <bar> | 3:EXACT <bar>(5) 7 <foo bar> <> | 5:CLOSE1(7) 7 <foo bar> <> | 7:END(0) Match successful! Freeing REx: "(bar)" $


Comment on Re^3: ${^MATCH} regex special variable(s) and /p regex modifier
Select or Download Code
Re^4: ${^MATCH} regex special variable(s) and /p regex modifier
by lidden (Deacon) on Oct 04, 2011 at 14:16 UTC
    Yes, but it seems anything but a literal string will make the variable defined.
    $ perl -wE 'my $s = "foo 123"; $s =~ /\d+/; say ${^PREMATCH}' foo

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://929512]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others having an uproarious good time at the Monastery: (8)
As of 2014-12-27 06:16 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    Is guessing a good strategy for surviving in the IT business?





    Results (176 votes), past polls