From: Ryan Davis <ryand-ruby@...>
Date: 2010-02-19T17:10:40+09:00
Subject: Re: Ruby conditionals subtlety?


On Feb 18, 2010, at 23:06 , Albert Schlef wrote:

> Farhad Farzaneh wrote:
>>> I should also point out: almost all of this is of no consequence. You 
>>> almost never use defined? on a local variable like this. You usually use 
>>> it on a const, ivar, cvar, or global, and all of those are unambiguous.
>> 
>> Thanks.  I sometimes use it in Rails partials rendering, where I may 
>> pass an optional local variable, but if it isn't passed, I want to set 
>> it to some default value.
> 
> BTW, I wonder,
> 
> In templates, local variables are created dynamically (e.g., the 
> programmer passes a hash of "variables" to the template engine). So how 
> can Ruby know, in the template code, that a "name" refers to a variable? 
> By default Ruby thinks names are method invocations and since there's no 
> assignment, Ruby has no way to know these are variables...

that's a rails question. Please take it to a rubyonrails forum (or dig up the code--but I really don't recommend that).