Front page | perl.perl5.porters |
Postings from June 2022
"Paul \"LeoNerd\" Evans" <leonerd@leonerd.org.uk> writes:
> On Fri, 24 Jun 2022 16:44:27 +0100
> "Paul \"LeoNerd\" Evans" <leonerd@leonerd.org.uk> wrote:
>
>> I was thinking that maybe it should be just exposed as a builtin::
>> function itself, perhaps as
>>
>> builtin::lexically_export $name, \&func;
>
> I've had a bit of a go at implementing this:
>
> https://github.com/leonerd/perl5/tree/lexically-export
>
>> Perhaps it should take a whole kv-list of name/ref pairs, so you can
>> export lots in one go:
>>
>> builtin::lexically_export
>> one => \&one,
>> two => \&two, ...
>
> It currently doesn't do this yet, but shouldn't be hard to add.
I think it should support this, since it's common to export multiple
things, and build up data structures of things to be exported, e.g.:
my %exportables = ( ... );
sub import ($class, @items) {
# [ validation here ]
lexically_export %exportables{@items};
}
instead of having to do
lexically_export $_ => $exportables{$_} for @items;
> In the process of writing it I've come up with some more questions, to
> which I don't have an easy answer:
>
> * Should it support things other than functions? Should we support
>
> lexically_export VAR => \my $scalar;
Yes.
> * If so, should names be sigil-prefixed?
>
> lexically_export '$VAR' => \my $scalar, '&func' => sub {...};
Yes, but …
> Instead, perhaps a compromise idea taken from the way Exporter.pm
> works; which is to say that sigils would be required for
> scalar/hash/array variables, but not required for regular functions.
>
> lexically_export
> name => \&function, # a regular function
> '$VAR' => \my $scalar, # a scalar variable
> '@VAR' => \my @arr, # an array variable
> '%VAR' => \my %hash, # a hash variable
>
> '&func' => \&func, # also permitted for symmetry, but not
> # required
>
> I.e. the model being "if no sigil is specified, presume &"; and
> additionally, error if the sigil doesn't match the thing being
> referenced.
Yes.
> I think this feels sane - does anyone disagree?
I think this is a good approach, for reasons of convenience,
consistency, and safety.
- ilmari
Thread Previous
|
Thread Next