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Re: Why views are useful, and why their syntax doesn't matter much

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Aristotle Pagaltzis
July 10, 2011 17:54
Re: Why views are useful, and why their syntax doesn't matter much
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* Father Chrysostomos <> [2011-07-11 02:20]:
> I can’t speak for Perl 6, but making something read-only in
> Perl 5 just feels un-Perl-5-ish. After all, we allow $^X
> assignment.

Heck it was only recently agreed that

    for (1,2,3) { ++$_; say }

should not complain about “modification of read-only value” nor
change the values in the optree but instead give you modifiable
copies. Arguably that is what one would expect to happen there
in the first place.

> If you want something more efficient than copying, we have
> copy-on-write for strings. Can we make perl use that more
> often? And isn’t copying an RV or a number just as fast as
> making a view?

Yes, I believe `my ($arg, $um, $ents) = @_` already has perfectly
sensible semantics that should be replicated by whatever syntax
becomes the default. If it can yield better performance too (as
defaulting to CoW would allow), all the better, but that should
not be the primary concern. As for aliases, anyone who wants one
should just be able to ask for one explicitly, along the lines of
`my (\$arg, $um, $ents) = @_` per the backslash-in-lvalue-context

Aristotle Pagaltzis // <>

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