Why the Greedy Ones are the Defaults

• Typical case:

        # $s contains a line of code:
        $s = '($label =~ tr/.//) < 3; # do not attach these';

        # Let's strip out comments
        $s =~ s/#.*//;

• $s is now:

        '($label =~ tr/.//) < 3; '

• If it weren't greedy, $s would be:

        '($label =~ tr/.//) < 3;  do not attach these';

• Suppose * were nongreedy by default....

• To get the expected behavior, you'd have to say

        # In the parallel universe where * is nongreedy
        $s =~ s/#.*$//;         

• But that would be inefficient because it would backtrack on every character!

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Copyright © 2002 M. J. Dominus