From: James Edward Gray II <james@...>
Date: 2007-04-18T03:42:54+09:00
Subject: Re: how to have a default argument

On Apr 17, 2007, at 12:59 PM, Kyle Schmitt wrote:

> Ohh.  So this is technically not argument number type overloading.   
> Dohh.
>
>
> ie: def foo(bar)
>     def foo(bar,manchu)
>     def foo(bar,manchu,biebelch)
>
> Which you can't do in straight ruby.  Or can  you?

Sure, multiple ways;

 >> def foo(bar, manchu = nil, biebelch = nil)
 >>   [bar, manchu, biebelch]
 >> end
=> nil
 >> foo 1
=> [1, nil, nil]
 >> foo 1, 2
=> [1, 2, nil]
 >> foo 1, 2, 3
=> [1, 2, 3]
 >> foo 1, 2, 3, 4
ArgumentError: wrong number of arguments (4 for 3)
         from (irb):7:in `foo'
         from (irb):7
 >> def foo(*args)
 >>   case args.size
 >>   when 1 then "Called with bar:  #{args.inspect}."
 >>   when 2 then "Called with bar and manchu:  #{args.inspect}."
 >>   when 3 then "Called with bar, manchu and biebelch:  # 
{args.inspect}."
 >>   else        raise ArgumentError, "wrong number of arguments"
 >>   end
 >> end
=> nil
 >> foo 1
=> "Called with bar:  [1]."
 >> foo 1, 2
=> "Called with bar and manchu:  [1, 2]."
 >> foo 1, 2, 3
=> "Called with bar, manchu and biebelch:  [1, 2, 3]."
 >> foo 1, 2, 3, 4
ArgumentError: wrong number of arguments
         from (irb):25:in `foo'
         from (irb):31

Hope that helps.

James Edward Gray II