From: Florian Gross <flgr@...>
Date: 2005-01-09T17:26:23+09:00
Subject: Re: Type inference in ruby

Trevor Andrade wrote:

> def foo(object)
> 
> return object.call(9, 7, 3)
> 
> end
> couldn't the type system figure out that object must respond to the call
> command and thus eliminate an error like:
> 
> foo(5)

class Fixnum
   def call(*args) end
end

Note that Ruby could not even insert a check at the beginning of the 
method as another Thread might dynamically define Fixnum#call.

> I guess I am also wondering about a lot of other things like why do you need
> multiple assignment in Ruby?  There doesn't seem to be any need for it since
> you can just modify an object by sending it a message eg x = x + 1 is the
> same as x.+(1).

I don't see the connection between the two and you are not even doing 
multiple assignment in your example.

Fixnum#+ does not modify the original receiver. It returns the result as 
a new Object. There are in place modifications in Ruby (String#gsub! 
etc.), but that has nothing to do with multiple assignment.