From: Robert Klemme <shortcutter@...>
Date: 2006-12-20T00:10:12+09:00
Subject: Re: Discovering the number of return arguments requested.

On 19.12.2006 12:21, Brad Phelan wrote:
> Eric Hodel wrote:
>> On Dec 19, 2006, at 01:20, Brad Phelan wrote:
>>
>>> Is it possible ( and I think not ) that you can discover if any 
>>> return arguments are requested when a method is called.
>>
>> Methods only ever return one Object.  (Sometimes that Object will be 
>> splatted, giving the illusion of multiple arguments.)
> 
> True. However that doesn't answer the question as
> to whether it is possible to discover if that single object is used
> or not. I suspect Ruby syntax would make this difficult to figure
> out.

Actually, a Ruby method does *always* return an instance (even without 
explicit "return").  Conversely there is nothing like a void function / 
method - there is always a value returned.

 >> def foo() end
=> nil
 >> foo
=> nil

> If the critical function is called as the last statement in another 
> function or block then the return object can get passed implicitly
> up the stack until something takes hold of it.

This is exactly what happens:

 >> def bar() 1 end
=> nil
 >> def foo() bar() end
=> nil
 >> foo
=> 1
 >> bar
=> 1

IMHO you are worrying too much about this: if a method has a meaningful 
return value it should be documented and returned no matter what the 
caller does.  If he chooses to ignore it that's his choice.  My 0.02EUR.

Kind regards

	robert