Says juerd: 
sub DELETE {
      my ($self, $key) = @_:
      $self->STORE($key, '');
}

[download]
That, unfortunately, doesn't work well. Suppose %h is tied to the string converted, and then you do delete @h{2,5}. You'd like to delete the n and the r, yielding coveted, but that's not what happens. Instead, Perl calls DELETE(2), which deletes the n, leaving coverted, and then DELETE(5), which deletes the t, not the r, leaving covered instead of coveted.

Of course, that's not your fault, but at present it can't really be made to work right. I was going to put in a patch to fix this (motivated by the same problem using delete with Tie::File) but I haven't gotten around to it yet. The easy solution is that if you're deleting a list of values, Perl should delete them in order from last to first instead of from first to last. That fixes the delete @h{2,5} problem, but unfortunately the same problem persists with delete @h{2,5,3}.

The patch I planned to make would allow the tied hash class to request that Perl call a special DELETESLICE method instead of making multiple calls to DELETE in such cases. It would follow the same form as the NEGATIVE_INDICES feature in the current bleadperl.

--
Mark Dominus
Perl Paraphernalia

In reply to Re: Are strings lists of characters? by Dominus
in thread Are strings lists of characters? by John M. Dlugosz

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