in reply to Why is this link parser only working the first time?

If you had turned warnings on you would have receieved a message about "cannot stay shared". I tried to explain the error in RE (3): BrainPain-Help, I never got any feedback on it so I have no idea whether it is or isn't understandable.

Anyways to fix your problem is simplicity, instead of writing: 

sub attachment_link_extractor { # ...

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write that as 
my $link_extractor = sub { # ...

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And then just pass the variable in to the constructor to LinkExtor.

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Re: Re (tilly) 1: Why is this link parser only working the first time?
by dave_aiello (Pilgrim) on Jan 20, 2001 at 01:19 UTC
    tilly:

    Thanks very much. This is an excellent solution because the code change is limited to a single line.

    What used to be: 

        sub attachment_link_extractor
            {
                my ($tag, %attr) = @_;

                push(@links, values %attr)
                    if (($tag eq 'a') &&
                        ($attr{href} =~ m/attachments/));
            }

      my $p = HTML::LinkExtor->new(\&attachment_link_extractor);

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    ... now becomes ... 
        $attachment_link_extractor =
        sub {
                my ($tag, %attr) = @_;

                push(@links, values %attr)
                    if (($tag eq 'a') &&
                        ($attr{href} =~ m/attachments/));
            };

      my $p = HTML::LinkExtor->new($attachment_link_extractor);

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    The only part of the your suggested change that confused me was the need to put a semicolon after the bracket that closes the subroutine. I don't remember ever writing Perl that way before, but, I keep forgetting that the subroutine itself is part of an assignment statement.

    Dave Aiello
    Chatham Township Data Corporation

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      Sorry, I should have remembered the semi-colon. That is the kind of detail I stopped thinking about, they just automatically go in when I write, and if I edit then run I expect to have Perl catch.

      You are right about why you need it. In the language used in perlsyn, the subroutine is now within a "simple statement" and you need to terminate the statement.

      As for writing Perl like that, I do it all of the time and recommend it whenever I get the chance. :-)

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