Re: [FWP] Comparing two arrays

[abigail@foad.org]

On Sun, Jul 23, 2000 at 05:18:16PM -0400, Jeff Pinyan wrote:
> 
> >> (especially if value happens to be an empty string, since the split would
> >> remove the empty trailing fields...).
> >
> >    map {(split /\0/ => $_, -1) [-1]}
> 
> Yup, I know.  Sadly, Perl doesn't optimize
> 
>   ($a,$b,$c) = (split)[-3 .. -1];
> 
> the same way it optimizes
> 
>   ($a,$b,$c) = (split)[0..2];  # [0..2] optional, I believe...
> 
> And if it DOES optimize this, I am highly unaware.  It'd be quite nice of
> Perl to do this.  How possible is this optimization?


I would be very surprised if Perl could. In general, I don't think it
possible to extract only the last N fields from a split without creating
all the fields, because you will never know how much the regexes consume
of the string if you don't start from the beginning.

But there might be a way to optimize it if it's determined that the regex
doesn't contain any metacharacters.


Abigail

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