in reply to Re: Simple stack implementation
in thread Simple stack implementation

He did use an array.

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Re: Re: Simple stack implementation
by Adam (Vicar) on Nov 18, 2000 at 01:48 UTC
    Yes, but the over-head of tieing it to a scalar is excessive.
[reply]
      I don't think 'excessive overhead' has any meaning without a context. It might be excessive for some applications and not for others.

      And I think the interface is sufficiently interesting that the overhead might be worth spending. Being able to write 

          $stack = newitem;

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      for a push operation and 
          $top = $stack;

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      for a pop operation is pretty clever.

      But one thing I would do differently is to resolve the fifo/lifo string to boolean in the TIESCALAR method instead of doing it over and over on every FETCH. Just change the TIESCALAR like this: 

      sub TIESCALAR {
    return unless $_[1] =~ /[fl]i[fl]o/i;
    my $stack = $_[1] =~ /([fl])i\1o/i;
)   return bless [$stack,[]], $_[0];
}

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      Then we can eliminate the regex from FETCH; the if line becomes simply: 
          if ($_[0]->[0]) {

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In Section Cool Uses for Perl