Why does my Perl regex cause an infinite loop? - regex

Question

I have some code that grabs the "between" of some text;
specifically, between a foo $someword and the next foo $someword.
However, what happens is it gets stuck at the first "between" and somehow the internal string position doesn't get incremented.
The input data is a text file with newlines here and there: they are rather irrelevant, but make printing easier.
my $component = qr'foo (\w+?)\s*?{';
while($text =~ /$component/sg)
{
push #baz, $1; #grab the $someword
}
my $list = join( "|", #baz);
my $re = qr/$list/; #create a list of $somewords
#Try to grab everything between the foo $somewords;
# or if there's no $foo someword, grab what's left.
while($text=~/($re)(.+?)foo ($re|\z|\Z)/ms)
#if I take out s, it doesn't repeat, but nothing gets grabbed.
{
# print pos($text), "\n"; #this is undef...that's a clue I'm certain.
print $1, ":", $2; #prints the someword and what was grabbed.
print "\n", '-' x 20, "\n";
}

Answer 1

Update: One more update to deal with 'foo' occurring inside the text you want to extract:
use strict;
use warnings;
use File::Slurp;
my $text = read_file \*DATA;
my $marker = 'foo';
my $marker_re = qr/$marker\s+\w+\s*?{/;
while ( $text =~ /$marker_re(.+?)($marker_re|\Z)/gs ) {
print "---\n$1\n";
pos $text -= length $2;
}
__DATA__
foo one {
one1
one2
one3
foo two
{ two1 two2
two3 two4 }
that was the second one
foo three { 3
foo 3 foo 3
foo 3
foo foo
foo four{}
Output:
---
one1
one2
one3
---
two1 two2
two3 two4 }
that was the second one
---
3
foo 3 foo 3
foo 3
foo foo
---
}