From: psy <psy@...>
Date: 2008-08-18T17:03:16+09:00
Subject: Re: What's difference?

Hier from Programming Ruby book. Its not exactly for this case, but i think it gets close : 

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When Ruby sees a name such as ``a'' in an expression, it needs to determine if it is a local variable reference or a call to a method with no parameters. To decide which is the case, Ruby uses a
heuristic. As Ruby reads a source file, it keeps track of symbols that have been assigned to. It assumes that these symbols are variables. When it subsequently comes across a symbol that might be
either a variable or a method call, it checks to see if it has seen a prior assignment to that symbol. If so, it treats the symbol as a variable; otherwise it treats it as a method call.
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There is also this example down below : 

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Note that the assignment does not have to be executed---Ruby just has to have seen it. This program does not raise an error.

a = 1 if false; a
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Greets

On Mon, 18 Aug 2008 15:29:04 +0900
Kyung won Cheon <kdream95@gmerce.co.kr> wrote:

> --- test1.rb ---
> 
> b = 1
> puts a if a = b
> 
> # NameError: undefined local variable or method `a' for main:Object
> 
> 
> --- test2.rb ---
> 
> a = 1 if false
> puts defined?(a)
> 
> # local-variable
> 
> 
> ###############
> # Help Me^^
> ###############