From: Dave Thomas <Dave@...>
Date: 2001-10-26T01:38:46+09:00
Subject: [ruby-talk:23316] Re: why the @ s ?

Tobias Reif <tobiasreif@pinkjuice.com> writes:

> Dave,
> 
> thanks for your explanation. But I'm still confused: (thanks for your 
> patience)
> 
>  > a = 10
>  > def fred
>  >   p a    #=> -:3:in `fred': undefined local variable or method `a'
>  > end
> 
> with ruby 1.6.3 (2001-03-19) [i386-cygwin] :
> --------------------
> a = 10
> def fred
>    p a      #=> no error
> end

you have to call 'fred' to get the error...

> --------------------
> 
> works:
> --------------------
> var01 = 'var01'
> 
> def print_var var
>    print var
> end
> 
> print_var var01 #=> prints 'var01'

Because you're passing 'var' in as a parameter


> doesn't:
> --------------------
> var01 = 'var01'
> 
> def print_var01
> 
>    print var01
> 
> end
> 
> print_var01
> 
> # 18:in `print_var01': undefined local variable or method `var01' for
> # #<Object:0x45aa028> (NameError)
> --------------------

var01 is not defined inside print_var01

> In the last example: how could I make it work without adding an @
> sign?

You can't. Local variables are no in scope within the method.

> in the last line? Since print_var01 is defined as method just above; why 
> doesn't Ruby treat it as such?

It does - the problem is the 'var01' variable.



Regards


Dave