From: Ilias Lazaridis <ilias@...>
Date: 2011-06-20T08:35:34+09:00
Subject: Re: CORE - Inconsistent Handling of Uninitialized Variables

On 20 Ιούν, 01:01, Gary Wright <gwtm...@mac.com> wrote:
> On Jun 15, 2011, at 5:00 PM, Ilias Lazaridis wrote:
>
> > I don't understand, why "p $xx" does not fail with and "not defined"
> > error.
>
> Because the parser 'sees' the variable $xx and defines it before "p $xx" gets executed.
[...] - (explanations, referring to why to locals cannot behave this
way)

I'll reduce this further down, dealing *only* with global variables.

(Please, if possible, avoid comparisons to the other variable types.)

-

$x_void

def make_nil_global(val)
  $x_undefined = val
end

p global_variables

-

Behaviour (ruby 1.9.2p180):

$x_void is added to the the global_variables (undefined, nil)
$x_undefined is added to the global_variables (undefined, nil)

Expected Behaviour:

$x_void is ignored (*not* added to global_variables, access would
raise error)
$x_undefined is added to the global_variables (undefined, nil)

-

I cannot see a use case, where placing $x_void into the
global_variables is *necessary*.

I possibly oversee something very fundamental, but the main rules for
my expectations are:

* variables come to existence when a value is assigned
* if the value cannot be determined, "nil" is assigned

.

--
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