calling in Ruby and Perl

[Mathieu Bouchard]

Question 1:

How would other languages get multiple return values from a Perl
procedure? How would code in that other language signal scalar vs list
context? what about the finer subdivisions of Perl context?



Question 2:

How would other languages call a Ruby procedure that expects something in
the proc-slot ? For example, if I have the following code:

        def each_recursively(&foo)
          each {|x|
            foo.call x
            x.each_recursively(&foo)
          }
        end

In Perl I would write code similar to the above:

        sub each_recursively{ my($self,$foo)=@_;
          $self->each(sub{ my($x)=@_;
            $foo->($x);
            $x->each_recursively($foo);
          });
        }

But this is not completely equivalent code, because here $foo is arg
number 1, which would be arg number 0 in Ruby; but in "&foo", the & means
it's the proc-slot (or "iterator"), which is out-of-band and so has no
numbered position in the argument list: it's the absolute-last argument;
it allows for rest-arguments while still allowing a proc to be passed (and
without having to pop the proc explicitly... etc)

so I thought that while a normal call would be like:

$receiver->$selector($arg0,$arg1,$arg2,...,$argN);

a Perl-to-Ruby call could be done like this:

$receiver->call_with_iter($selector,[$arg0,$arg1,$arg2,...,$argN],$proc);

or:

$receiver->call_with_iter($selector,$proc,$arg0,$arg1,$arg2,...,$argN);

or:

$receiver->call_with_iter($selector,$arg0,$arg1,$arg2,...,$argN,$proc);

or:

call_with_iter(sub {
        $receiver->$selector($arg0,$arg1,$arg2,...,$argN);
}, $proc);



so... what do you think?



matju