Re: Re: Re: Bug with lists?

[merlyn]

empty agreed, so it should be undef no?

I think this is where you are taking a leap of faith, and leaping in the wrong direction. {grin}

In fact, Perl hints the contrary in perldoc perldata:

       You may have an optional comma before the closing
       parenthesis of a list literal, so that you can say:

           @foo = (
               1,
               2,
               3,
           );

So there, you're not getting 1,2,3,undef. Just 1,2,3. An extra embedded syntax-only comma was formerly illegal (I believe). I'm a bit surprised to see that it's now being nicely ignored, just as the trailing comma had been, but it's not totally inconsistent with the trailing-comma-ignored feature.

Conclusion: no bug, although not precisely documented to work with embedded comma as well as trailing comma.

-- Randal L. Schwartz, Perl hacker

[demerphq]

Thanks merlyn, this seems like a credible explanation. Although as I said in the CB it seems like a bad call (contrary to DWIM, as well as the behaviour of about every other language.)

Nevertheless I would like to post this to perl5porters, if only to get the documentation improved. That would be the correct forum wouldn't it?

Yves / DeMerphq
--
When to use Prototypes?

[tilly]

This has been posted to p5p in the past. See here. FWIW I was said user, and that was less than 6 months after I started learning Perl.

IMHO the best possible documentation is to firmly get down Perl's idea of what a list is versus what a scalar is. If you understand what a list is, then it is obvious that ,, shouldn't insert an undef. If you don't, particularly if you are translating some VB code that uses commas as placeholders...

[demerphq]

Well, its nice to know im in good company. /ducks ;-)

Its true what you say about list context. And to be honest prior to this I would have said that I _did_ grok it. But it appears I am wrong. The fact that this wasn't docmented under perlop (which as Ive been harping about is where I would have expected this behaviour to be documented) is what threw me.

Anyway, this is a lesson that won't be forgotten any time soon, if at all. :-)

Yves / DeMerphq
--
When to use Prototypes?