The prototypes found in C allow functions to behave differently, given different arguments: 
int product (int x, int y) {
  return x * y;
}

char *product (char *company, int prodID) {
  /*
    magic to return name of product
    related to prodID in the given company
  */
}

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Now, in Perl, we can do this ourselves in the function, by checking the contents of @_, since Perl doesn't differentiate between strings and numbers (or types of numbers) like C does. (But the practice of having a function do totally unrelated things is A Bad Thing, and lends itself to confusion.)

How would you C-ize this Perl function? 
sub foo {
  die "foo() needs at least one argument" if !@_;
  (my($x,$), local($z)) = @_;
  $y ||= 10;
  $z ||= $x * $y;
  # ...
}

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Maybe something like 
sub foo (
  my($x) :req,
  my($y) ||= 10,
  local($z) ||= ($x * $y)
) {
  # ...
}

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I find that hideous. I really think I would find any type of variable-based prototyping in Perl pretty ugly.

japhy -- Perl and Regex Hacker

In reply to C-like Function Prototypes by japhy
in thread sub ($self,$var,@arr) {} by raptor

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