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Re: Poor Man's Perl6 Exegesis (you get what you pay for)

by mikfire (Deacon)
on Jan 24, 2002 at 23:45 UTC ( #141297=note: print w/ replies, xml ) Need Help??


in reply to Poor Man's Perl6 Exegesis (you get what you pay for)

I am uncertain if I should update my previous node or not. As I am attacking a seperate portion of this, I believe I am correct in making a new node.

sub myimport($exp_from : *@symbols=() : *@options=())
What does this do? I have been over the related Apocalypse and Exegesis ( part 3 ) and I think the idea here is to allow myimport to be called with lists instead of arrays.

According to TheDamian in Exegesis 3, page 1, the @ will cause perl6 to expect either an array or an array reference as the parameter. If we were to declare a perl6 sub like this:

sub foo( @bar )
and called it like this:
&foo( "a", "b" );
we would generate an error ( at compile time? ).

If we really want foo to be called with a list, we need to put the flattening star in the sub definition:

sub foo( *@bar )

But, later on in the same tome, we are told that this will have the standard perl5 affect of slurping the remainder of the parameters.

I am guessing this to be an error on BrentDax's part. I believe BrentDax was attempting to allow myimport to be called with lists, but forgot that the flattening star would behave exactly as we expect from perl5. If I have missed something, I would really appreciate being corrected.

update: Changed a bit of wording in the last paragraph. Mik
mikfire


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(Ovid) Re(2): Poor Man's Perl6 Exegesis (you get what you pay for)
by Ovid (Cardinal) on Jan 25, 2002 at 00:08 UTC
    sub foo( @bar ){...} &foo( "a", "b" );

    As I read things, yes, this is an error. The flattening star will be necessary to slurp up the rest of the goodies. I suspect that this is going to be a source of bugs for many people switching to Perl6. Also, I suspect the following will trip people up:

    @*ARGS; # was @ARGV

    The star between the sigil and the variable name, I believe, is how we will now be referring to special globals. Thus, @*ARGS != @ARGS.

    Cheers,
    Ovid

    Join the Perlmonks Setiathome Group or just click on the the link and check out our stats.

      Not true. @*ARGS and @ARGS are the same thing, unless you define a new @ARGS in your scope. If that happens, you can still access the global @ARGS as @*ARGS.

      =cut
      --Brent Dax
      There is no sig.

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