Re: array or scalar, that's the question

[Parham]

well it seems like no matter what you do... you're going to end up with an array cuz that's what your returning from &someonesFunc() (you don't need the ampersand on that btw). I think the solution you already have is a very good one and i can't see why you'd want to even change it.

In both cases though, you're always going to have an array, either with one or more elements.

[hotshot]

to clear things up a little. the function I use (someonesFunc() in the last post) is something from the format:

if ($x) {
   return $foo;   # returns scalar
}else{
   return @bar;   # returns array
}

I just thought there's a better way then mine to know what it returned, but if you suggest that what I did is good then what that's good enough for me.
Thanks.

Hotshot

[Fastolfe]

Differentiating between a "scalar" and an "array" is meaningless here. When you say "return @bar" Perl flattens @bar into a list.

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

return $foo;       # (3)
return @bar;       # (1, 2, 3)

In a scalar context, both of these versions will return 3 (the last element in the list returned). In a list context, you get 3 or 1, 2, 3. Just returning @bar, though, is sufficient for both cases, because it's your calling code that would want to act on the results. Make sense?

If you're wanting to return a real solid array (so that you can return @foo, @bar without flattening it into one big list), you need to return references to each array.

return (\@foo, \@bar);
...

my ($fooref, $barref) = your_function();

[Juerd]

When you say "return @bar" Perl flattens @bar into a list.

That's what happens in _list_ context. If the sub is called in scalar context, @bar will also be in scalar context and thus return the number of elements in @bar.



sub foo {
    my @foo = qw(a b c d);
    return @foo;
}
sub bar {
    return qw(15 4 3 12);
}

print        foo(), "\n"; #   list context => abcd\n
print scalar foo(), "\n"; # scalar context => 4\n
print        bar(), "\n"; #   list context => 154312\n
print scalar bar(), "\n"; # scalar context => 12\n

Explanation: a list returns its last element in scalar context, an array returns the number of elements in scalar context.

2;0 juerd@ouranos:~$ perl -e'undef christmas'
Segmentation fault
2;139 juerd@ouranos:~$