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Postings from September 2009
* Ben Morrow <ben@morrow.me.uk> [2009-08-29 15:25]:
> First: I don't like the ro-alias default at all. I would much
> prefer a cow-alias
Is there any user-visible difference between a copy and a COW
alias? If not, there’s no such thing as a COW alias as far as
the user is concerned… it’s just an implementation detail.
> for one thing, it's not at all clear how 'deep' the
> readonlyness should go.
The only sane option IMO is that it be completely shallow.
I mean, how is that question different from asking how deeply
a copy should copy? Seems to me the answer should be the same
in both cases, for the same reasons.
> sub foo (@a) { # expects scalars, creates ro aliases
> sub foo (\@a) { # expects array, creates ro alias
> sub foo (!@a) { # expects scalars, creates rw aliases
> sub foo (!\@a) { # expects array, creates rw alias
> sub foo (=@a) { # expects scalars, creates copies
> sub foo (=\@a) { # expects array, creates (1-level deep) copy
Like the :() proposal I find this is too much punctuation.
I would prefer a slightly more keywordy notation, maybe (to
follow existing precedent in Perl) something like attribute
synax:
sub foo ( @a) { # expects scalars, creates ro aliases
sub foo (\@a) { # expects array, creates ro alias
sub foo ( @a : rw) { # expects scalars, creates rw aliases
sub foo (\@a : rw) { # expects array, creates rw alias
sub foo ( @a : copy) { # expects scalars, creates copies
sub foo (\@a : copy) { # expects array, creates (1-level deep) copy
Be a bit shorter and lighter-looking than `is` and also leaves
whitespace style up to the user (something Abigail will surely
appreciate :-) ).
> We already have
>
> state $x = 4;
>
> which isn't in any way an ordinary assignment
Good point.
> so what's wrong with
>
> alias $x = $y;
>
> which has the advantage of being compatible with Data::Alias in
> simple cases?
Yeah, I like this.
Regards,
--
Aristotle Pagaltzis // <http://plasmasturm.org/>
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