Topic awaiting preservation: ...And on your left, a Perl subroutine...

I know about using 'shift()', but

How do you get a return value from a sub in Perl?


Code - CGI - links - DHTML - Javascript - Perl - programming - Magic - http://www.twistedport.com
ICQ: 67751342

Here is a quick little sub that shows you how to return a value. It's pretty straight forward:

sub parse_template {

  my ($self, $file, @vars) = @_;



  $file             or  return $self->error ('PAGEERR', 'WARN', '[empty]');

  $file =~ /\.\./   and return $self->error ('PAGEERR', 'WARN', $file);

  -e $file          or  return $self->error ('PAGEERR', 'WARN', $file);

  -r _              or  return $self->error ('PAGEERR', 'WARN', $file);

    

  require GT::Template;

  my $vars = $self->load_template_vars(@vars);



  return GT::Template->parse($file, $vars, { escape => 1 });;

}

I'm returning an object in this one but you can return just about anything. I always try to return at least a "true" value, or a "false" if something broke, when I build subs. It makes the subs quite a bit more portable.

Regards,
Charlie

What's nice about Perl is you can return a list of things...

sub mysub {
return (3,4,5);
}

my ($a,$b,$c) = &mysub();

(Apologies if I got the syntax wrong, Perl is weird and I don't use it much)

$subValue = returnScript();



sub returnScript {

    return(1);

}

subVal = 1

There is also that slime mention

($val1, $val2, $val3) = returnScript();



@vals = returnScript();



sub returnScript {

    return(1,2,3);

}

val1 = 1
val2 = 2
val3 = 3

vals[0] = 1
vals[1] = 2
vals[2] = 3

so, you're saying is- all I need is the 'return();' function?


Code - CGI - links - DHTML - Javascript - Perl - programming - Magic - http://www.twistedport.com
ICQ: 67751342

Well, yes. But technically speaking, return isn't a function. I'm tempted to say it's an operator, but I'm not sure, so I'm going to look it up...

Yup, it's an operator. Don't be fooled by the fact that I put parenthesis after it. The parenthesis in that case were a container for a list. The list was being returned.

return 4;

is a completely valid statement.

(For the record, while loops aren't functions either, they're a "control structure". Same for if blocks and for loops and some other things.)

note the return statement is not even always needed, if not explictly called the sub will automatically return the value of the last statement.
try this.

sub no_return {
my $ret = "This is what is returned";
}
print no_return();





.:[ Never resist a perfect moment ]:.

ok but subroutines do not need parenthsis either.

for example

sub this {

  my ($x, $y) = @_;

  print "$x, $y\n";

  return 5, 6, 7;

};



my @x = this "that", "this";

foreach my $b (@x) {

  print "$b\n";

};

produces the results

that, this
5
6
7

also.. you can specify a subroutine as

sub this {
"that";
};

and when you call this... you get that back.... this is how perl makes constants in the packages.

Rahly

[This message has been edited by Petskull (edited 07-07-2003).]