m modifier not doing what I'm expecting?

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

Hi, I'm trying to work out why this regex isn't working as I'm expecting. I'm using the /m modifier to make it treat the data as "new lines" per row, but it seems to just keep looping through on the first one:

my $data = <<_DATA_;
== Example header 1

== a

f

== Header 2 example

==== sub header

a sub sub header :)

== Testing header item with some stuff in

[[fffsdfsdf]]
_DATA_

while ($data =~ /^\=\= (.+?)$/m) {
    print "FOO: $1 \n";
}
[download]

..just keeps printing out:

FOO: Example header 1 (repeatedly, til you kill the script)

Can anyone point me to where I'm going wrong?

TIA!

Andy

Comment on m modifier not doing what I'm expecting? Download Code

Replies are listed 'Best First'.
Re: m modifier not doing what I'm expecting? by Eliya (Vicar) on Dec 21, 2011 at 12:15 UTC
You also want the `/g` modifier. (`/m` alone matches from the beginning every time, thus the endless loop...)	[reply] [d/l] [select]
Re^2: m modifier not doing what I'm expecting? by ultranerds (Hermit) on Dec 21, 2011 at 12:28 UTC
Aaah thanks - so was just missing the /g ... works like a charm now. Thanks! Andy	[reply]
Re: m modifier not doing what I'm expecting? by moritz (Cardinal) on Dec 21, 2011 at 12:14 UTC
Note that without `/s`, the dot . doesn't match a newline \n character. Perl 6 - second systems done right	[reply] [d/l]
Re^2: m modifier not doing what I'm expecting? by Anonymous Monk on Dec 21, 2011 at 12:56 UTC
This is not a problem here, as the dot isn't supposed to match a newline.	[reply]
Re^3: m modifier not doing what I'm expecting? by moritz (Cardinal) on Dec 21, 2011 at 13:24 UTC
Then maybe you should elaborate on what output you want. Perl 6 - second systems done right	[reply]
Re^4: m modifier not doing what I'm expecting? by Anonymous Monk on Dec 21, 2011 at 13:46 UTC

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