From: 7stud -- <bbxx789_05ss@...>
Date: 2009-09-16T05:21:29+09:00
Subject: Re: .map.with_object(3){|v|v+3} #=> 3 Is this a bug?

David A. Black wrote:
> Hi --
> 
> On Wed, 16 Sep 2009, 7stud -- wrote:
> 
>>>> ------------------------------------------------------------------------
>>>    tens_hash = array.each_with_object({}) {|n,obj| obj[n] = n * 10 }
>>> call on it:
>>>>
>> 2) Why (*args) ?
> I read it as just shorthand for "miscellaneous other arguments". I
> don't know whether there's a better way to denote that.
>

When I see *args as a parameter variable, I expect the parameter 
variable to always reference an array.  For instance:

def meth(*args)
  p args
end

meth(1, 2)
meth("red")

--output:--
[1, 2]
["red"]


So the *args confuses me in the ri info:

------------------------------------------------- Enumerator#with_object
     e.with_object(obj) {|(*args), memo_obj| ... }
     e.with_object(obj)

     From Ruby 1.9.1
--------------


As my examples show, sometimes args will be an array and other times it 
won't.



>> In the definition:
>>
>>> e.with_object(obj) {|(*args), memo_obj| ... }
>>
>> 3) Why 'memo_obj' and not 'obj'?
>>
>> Even though two different variable names makes it hard to track what is
>> going on, the following assignment takes place:
>>
>> memo_obj = obj
> 
> I think it's schematic. obj is not necessarily the variable "obj";
> it's just an object:
> 

I see.


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