Functions Signatures

[nofernandes]

Hello,

Does someone knows how can i declare a function signature at the start of the code!? Like is done in C or Java??

Example:

If i had this funcion:

sub Hello{
my($text)=@_;
print $text;
}

How can i show at the beggining of the file that this function exists without comments of course..

Something like this:

sub Hello($text);

$a="Hello World";
Hello($a);
sub Hello{
my($text)=@_;
print $text;
}

Does anyone knows? Is it possible?

Thanks...

[Abigail-II]

You can always declare subs:

    sub Hello;

It doesn't show what kind of arguments it expects, because the definition of the sub doesn't see so either. You could use prototypes, but be aware of the results. Prototypes aren't as useful as you may think. If you use prototypes, write:

    sub Hello ($);

but then you have to repeat that prototype when defining the function:

    sub Hello ($) {
        my ($text) = @_;
        print $text;
    }

Abigail

[crouchingpenguin]

In addition, you can also

use subs qw( sub_name_one sub_name_two etc );

cp
----
"Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic."

[nofernandes]

Ok.. but so i cannot show the arguments of the file?

Ok thank you very much!!

[Abigail-II]

Arguments of the file? What do you mean by that?

Abigail

[broquaint]

Unfortunately perl5 doesn't natively support function signatures, as we'll be getting in perl6. Although there are likely to be some modules on CPAN to do the job such as Attribute::Signature. As it stands the closest thing perl has to function signatures, is the prototype, but it's very far removed from the general interpretation of function signatures, and isn't looked upon too kindly as Tom Christiansen thoroughly illustrated in Far More Than Everything You've Ever Wanted to Know about Prototypes in Perl.
HTH

_________
broquaint

[Nkuvu]

Question's been answered, but I have one of my own. Um, why would you feel the need to do this?

When I write scripts I put all subroutines at the end of the script, and don't have any problems calling them in the main portion of the script.

Maybe it's just for developer information so they don't have to scroll to where your subs are to see what's available?

[blue_cowdawg]

Maybe it's just for developer information so they don't have to scroll to where your subs are to see what's available?

That's what comments are for. If you insist, put a set of comments in the beginning of your code that provide an "index" to the functions you define.

Better yet, make it POD so you can do neat things later on like generate MAN pages, HTML, etc.

---

Peter L. Berghold	Brewer of Belgian Ales
[e-mail]	www.berghold.net
Unix Professional

[Nkuvu]

Well, yes, that would be my approach. But it was the best idea I could come up with for doing this.

[dragonchild]

If they're that lazy that they won't use a search function .....

------
We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.

Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.