Re: exists $foo[7] and delete $foo[7]

[Gurusamy Sarathy <gsar@ActiveState.com>]

On Thu, 13 Jan 2000 17:26:13 GMT, Pete Jordan wrote:
>Gurusamy Sarathy wrote:
>> scalar(@array) and $#array are still related in the same way as before,
>> but it _would_ be semantically cleaner for the former returning just the
>> number of initialized values.  But we really can't do that without
>> breaking compatibility.
>
>How so? There's nothing to break compatibility with: The old (current)
>definition of C<scalar @foo> would be "the number of elements that exist
>in the array (excluding putative non-existent elements that can't yet,
>errm, exist)"...
>
>As long as you carry on counting /undefined/ values, nothing can break.
>Anyone who did C<@foo=(1, 2, 3); delete $foo[1]; $foo[scalar @foo]=4;>
>would get what they deserved ;)

If we made scalar(@foo) only count the initialized valuse (a.k.a values
that exist), the following code will break:

    $foo[3] = 4;  # @foo[0,1,2] are uninitialized, even in perl 5.005
    if (@foo > 2) {
        ...
    }

I don't think we can do it.  Besides, it possibly reads better to extend
values() to do that instead.


Sarathy
gsar@ActiveState.com

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Follow-Ups from:

pete@horus.cix.co.uk (Pete Jordan)

References to:

Pete Jordan <pjordan1@email.mot.com>

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