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Re: howto strip the first char of a string?

by herveus (Prior)
on Sep 08, 2004 at 13:34 UTC ( [id://389356]=note: print w/replies, xml ) Need Help??


in reply to howto strip the first char of a string?

Howdy!

Well, there's always chop reverse; reverse;

yours,
Michael

Replies are listed 'Best First'.
Re^2: howto strip the first char of a string?
by ihb (Deacon) on Sep 08, 2004 at 15:21 UTC

    Did you try running that? Perhaps you meant the pseudo-code reverse; chop; reverse; which spelled out in Perl would be $_ = reverse; chop; $_ = reverse;?

    If not, I don't understand how you'd expect chop reverse; reverse; to do anything useful.

    ihb

    Read argumentation in its context!

      Well, in the insane-o universe where reverse was an lvalue, chop reverse is all you'd need. That, however is certainly not the case. It's funny just to think, though, about someone implementing an lvalue reverse function... can you lvalue a tied scalar? I should look into that :-p
      ------------ :Wq Not an editor command: Wq
        And, amazingly... it completely works!
        package Tie::ReverseScalar; sub TIESCALAR { my $class = shift; return bless \$_[0] => $class; } sub FETCH { return reverse ${$_[0]}; } sub STORE { ${$_[0]} = reverse $_[1]; } sub DESTROY { undef ${$_[0]}; } 1;
        and then:
        use Tie::ReverseScalar; sub Reverse :lvalue { my $x = @_ ? \$_[0] : \$_; tie $x, 'Tie::ReverseScalar', $$x; $x } $_ = 'foo'; chop Reverse; print; __END__ oo
        Now, of course, that's not the way that reverse actually works... but isn't that fun?

        Update: oops, I had written that this output "fo" (which wouldn't have been interesting at all), but it actually outputs "oo" (which is what makes it cool). Thanks, BrowserUK, for pointing out the typo.

        ------------ :Wq Not an editor command: Wq

        Yes you can. You don't even need to go as far as you're thinking about.

        BEGIN { sub funky_reverse : lvalue {} *CORE::GLOBAL::reverse = \&funky_reverse; }

        It doesn't help you, though. You really want to return an alias (or a list thereof), not any old lvalue(s). And that's not something you can do in vanilla Perl. You need something like Data::Alias.

        Makeshifts last the longest.

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