From: Peter Vandenabeele <peter@...>
Date: 2011-01-26T07:53:55+09:00
Subject: Re: The finer points of postfix conditionals.

Robert Klemme wrote in post #977145:
> On Mon, Jan 24, 2011 at 3:22 PM, Jon Leighton <j@jonathanleighton.com>
> wrote:
...
>> and even:
>>
>> if false
>> foo = 1
>> bar = 2
>> end
>>
>> (results in both foo and bar being assigned nil)
>
> This is not exactly true: foo is not "assigned nil" but rather is foo
> initialized as a local variable and initially a variable refers nil.
> There is no assignment but because you have an assignment in code
> (even though it's no executed) the local variable comes into existence
> (see above).

To understand this better, I used the method 'defined?'.
Would 'defined?' be a correct way to determine if a name was
already 'initialized as a local variable' in this case?

$ rvm use 1.9.2  # (same behavior in 1.8.7)
Using /home/peterv/.rvm/gems/ruby-1.9.2-p136
$ irb
001:0> defined?(x)  #=> nil
002:0> if false
003:1> x = 10
004:1> end  #=> nil
005:0> defined?(x)  #=> "local-variable"
006:0> x  #=> nil

Thanks,

Peter

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