[pm-h] Interesting Blog Posts on Context & Array vs List

[Mark Allen]

I don't know much programming you do in other languages, but honestly, it's a little bit uh, disappointing that Perl 5 can't unpack @_ into variables automatically after 25 years. 

What is it laying the groundwork for?  Having a first class mop/object system is the most immediately obvious extension.  Whether you think mop/method signatures are Good Things or not I couldn't say, but I think it's long overdue for both.

So I say, more like this please.

Mark



On Friday, February 21, 2014 10:44 AM, B. Estrade <estrabd at gmail.com> wrote:
 
I am just wondering, what's it a start for? I don't get all upset about language features because this is all optional anyway, but I am curious about what groundwork this is laying.

Brett



On Fri, Feb 21, 2014 at 10:13 AM, Mark Allen <mrallen1 at yahoo.com> wrote:

I think it's a pretty great 1st start.  And you *can* have a slurpy arg in the final position. Plus everything's still in @_ if you want to be traditional or modify stuff using topic variables.
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>On Friday, February 21, 2014 9:05 AM, B. Estrade <estrabd at gmail.com> wrote:
> 
>So I guess with the signatures, the answer is "it depends" since it'll work with signatures as one might expect (i.e., the flattened array would have to have each element correspond to a sig parameter) or the sig parameter may very well be data type passed by reference.
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>I read up on the signature thing, and I doubt I'll find it useful for anything. It's also experimental, so requires an explicit feature 'use' and can be taken out at any time.
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>http://search.cpan.org/~tonyc/perl-5.19.9/pod/perlsub.pod#Signatures
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>It seems a squishy and a little general, maybe it'd be better if one could specific the Perl data type (scalar, hashref, arrayref, etc) via the signature definition.
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>Brett
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>On Fri, Feb 21, 2014 at 8:03 AM, Uri Guttman <uri at stemsystems.com> wrote:
>
>On 02/21/2014 08:13 AM, B. Estrade wrote:
>>
>>On Wed, Feb 19, 2014 at 2:35 PM, Mark Allen <mrallen1 at yahoo.com> wrote:
>>>
>>>
>>>When subroutine signatures are released in 5.20, you'll be able to do
>>>>
>>>>sub foo ($self, $foo, $bar, $baz) {
>>>>    $foo ||= 'default';
>>>>    $baz //= 0;
>>>>
>>>>    ...;
>>>>}
>>>>
>>>>Yay!
>>>>
>>>>
>>>
>>>How will this behave if you call the method with foo(@a, at b, at c, at d) versus
>>>foo(\@a,\@b,\@c,\@d) ?  Does list flattening still occur in this case
>>>necessitating the use array references if you want to pass one array per
>>>parameter?
>>>
>>>
>>
sub calls always flatten into @_. the only way to pass individual arrays is by reference. prototypes (not recommended in most cases) do allow arrays to be parsed as single args but they are actually passed as references.
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>>
>>uri
>>
>>
>>-- 
>>Uri Guttman - The Perl Hunter
>>The Best Perl Jobs, The Best Perl Hackers
>>http://PerlHunter.com
>>
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>>
>
>
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