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Re: Predefining sub Parameters

by moot (Chaplain)
on Jun 22, 2005 at 17:29 UTC ( #469107=note: print w/ replies, xml ) Need Help??


in reply to Predefining sub Parameters

If you want to provide a compile-time check that parameters passed to a function are of the correct type, use a prototype:

sub functionname($@$) { ... }
The problem with this example is that perl flattens the @ and second $ parameter into one list, so your function wouldn't know where the second parameter (the @) ends.

There are some techniques in the cookbook and other literature that you might want to investigate, such as mimicking behaviour of built-ins with function prototypes. Some of these techniques can be used to alleviate the problem I've identified above.

You may also think about having your function accept only a hash (actually, a list of arguments your function will treat as a hash), and requiring callers to use named parameters:

sub functionname { my %hash = @_; # Validate keys of hash here } functionname(param1 => 1, param2 => 2, ...);
Did I mention There's More Than One Way To Do It? ;)

Now hiring in Atlanta. /msg moot for details.


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