I am trying to debug my understanding of the matching operator.
When invoked with the g modifier in list context, I thought that
the return value is a list of all possible matches. If capturing
parentheses are used, then the list is the set of all $1, $2, etc
captured.
The following bit of Perl:
#!/bin/perl -w
$" = '-';
$string = "a:b c:d";
@list = ($string =~ m/(\w):(\w)/g);
print "list=@list\n";
$string = "a:b:c";
@list = ($string =~ m/(\w):(\w)/g);
print "list=@list\n";
prints out:
list=a-b-c-d
list=a-b
I understand the first line of output, but it seems to me that
the second line of output should really be:
list=a-b-b-c
This is because the (\w):(\w) can match a:b and also b:c. It appears
that the regex engine finds the first match of a:b and then starts
the next matching attempt after the b, in which case it cannot find the
b:c match. I expected the next matching attempt to start after the a,
so that the b:c match would also be found.
I have read the Camel book chapter on this & the perlop man page,
but they don't really have a lot to say about this...
grain_of_sand