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Postings from August 2013
On 15 August 2013 16:22, Ricardo Signes <perl.p5p@rjbs.manxome.org> wrote:
> * Father Chrysostomos <sprout@cpan.org> [2013-08-14T12:03:29]
>> Ricardo Signes wrote:
>> > « $x->@* acts exactly like @$x » is the rule. "Except in interpolation" would
>> > be the exception.
>>
>> So we allow "$x->@*" and "$$x->@*" and "$x->$*->@*".
>>
>> What about the brace forms? How far does the equivalance of "@{...}"
>> and "...->@*" hold?
>>
>> "@{$foo}" --> "$foo->@*" # 1
>> "@{$foo[0]}" --> "$foo[0]->@*" # 2
>> "@{*$foo}" ??? # 3
>> "@{$foo->**}" --> "$foo->**->@*" # 4
>> "@{$foo->()}" --> "$foo->()->@*" # 5
>> "@{$foo++}" --> "$foo++->@*" # 6
>> "@{$foo ? bar() : []}" => "$foo ? bar() : []->@*" # 7
>
> We allow ->@* at the end of an expression that we would've allowed up to that
> point. Of your examples above, which I've taken the liberty of numbering, #1
> and #2 qualify. Of the rest, none do.
>
> So far, I don't feel like I've seen a real argument that this is complicating
> the language. From my thready knowledge of the guts here, I also think the
> changes to the internals are pretty minor, but I'm happy to be proved wrong.
>
> That said, I have softened just a little because I got to thinking that what
> we'd really benefit from is a generic "interpolate this expression" syntax,
> which is in Ruby as "foo #{ expr } bar" or the same in Perl 6 without the
> octothorpe.
>
> In Perl 5, of course, we have this in a sense: "foo @{[ expr ]} bar" and "foo
> ${\ expr } bar". Possibly that's as good as it gets, since such a syntax would
> need to either force one context or have two forms. And either way, it's
> circumfix.
>
> So: "@{ $foo->[0] }" isn't so bad; generic interpolation form
>
> We lose more simplicity with:
>
> "@{ $foo }[0,2]"
> vs.
> "$foo->@[0,2]"
>
> ...because the idea that "@{...}" is "generic interpolation" no longer holds
> together.
I know you put a lot of effort into this one so I am sorry to say
this, but I am pretty sure we will regret adding this syntax.
I hope I am wrong of course.
cheers,
Yves
--
perl -Mre=debug -e "/just|another|perl|hacker/"
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