I think its probably cause your substituting stuff into content, making the string different when it tries to do a second match...

Oh!!!!! Good point. Didn't think Perl would bomb on that. Need to go check it out. Thanks.

Cheers,
Ovid

Update: Oops. Just noticed that tye pointed out the same problem and I've verified that it's the bug. Here's a bit of sample code that can reproduce it (don't do this at home, kids):

#!/usr/bin/perl 

$string = "1";

# Infinite loop caused by modifying the string we are matching against
+ in while statement

while ($string =~ /(\d)/g) {
    $match = $1;
    $string =~ s/$match/$match/;
}
print $string;
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Update 2: After reading through Boogman and tilly's comments below, I'll have to see what I can do to reproduce the /e error. It was rather frustrating.

The /e causes the right hand side of s/// to be handled as code to eval. Well, since we are deliberately matching Perl code with this regex, this solution tends to choke quite spectacularly.

Hmmm... Thats strange. I decided to fool around with it and tried this out:

my $i = 1;
my $string = 'print "hello";';
my $content = 'print "hello";$x + 2; print "hello";print "hello";print
+ "hello";';

$content =~ s/($string)/$1.$i++."\n"/ge;

print "$content\n";

eval $string;
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and it printed out

print "hello";1
$x + 2; print "hello";2
print "hello";3
print "hello";4

hello
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It doesn't seem that it executed the print statement that was matched, even though if we hand the string directly to exec, it does print out hello.

Right hand side, not left:

$str = "Hello world\n";
$str =~ s/o/print "Got an o!\n"/eg;
print $str;
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