Forum: Ruby Ruby namespace question

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Zhao Y. (Guest)
on 2009-01-21 03:13
I require two ruby files which include two classes with the same name.
how can I specify which class I use?
Ryan D. (Guest)
on 2009-01-21 03:45
(Received via mailing list)
On Jan 20, 2009, at 17:11 , Zhao Yi wrote:

> I require two ruby files which include two classes with the same name.
> how can I specify which class I use?

class X; end # x.rb
class X; end # y.rb

same class, only one to specify. Files mean nothing in ruby, they're
just vehicles for the parser.
Zhao Y. (Guest)
on 2009-01-21 03:51
Ryan D. wrote:
> On Jan 20, 2009, at 17:11 , Zhao Yi wrote:
>
>> I require two ruby files which include two classes with the same name.
>> how can I specify which class I use?
>
> class X; end # x.rb
> class X; end # y.rb
>
> same class, only one to specify. Files mean nothing in ruby, they're
> just vehicles for the parser.

For this code:

require 'x.rb'
require 'y.rb'
X.new     #which class it uses, can I specify the class like x.X or y.X?
Tom C. (Guest)
on 2009-01-21 04:16
(Received via mailing list)
Zhao Yi wrote:
>>
>> same class, only one to specify. Files mean nothing in ruby, they're
>> just vehicles for the parser.
>>
>
> For this code:
>
> require 'x.rb'
> require 'y.rb'
> X.new     #which class it uses, can I specify the class like x.X or y.X?
>
Why not answer this empirically? Try it out!

t.

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Zhao Y. (Guest)
on 2009-01-21 04:21
Tom C. wrote:
> Why not answer this empirically? Try it out!

I have tried but failed. This is my code:

logger=log4r.Logger.new

and I got the error: undefined local variable or method log4r
Justin C. (Guest)
on 2009-01-21 04:30
(Received via mailing list)
Zhao Yi wrote:
>
>

I think you want

logger = Log4r.Logger.new

or

logger = Log4r::Logger.new

But, glancing at the docs, you also need to specify a name for it, like

logger = Log4r::Logger.new "mylog"


Hope that helps.

-Justin
Zhao Y. (Guest)
on 2009-01-21 04:33
yes,

logger = Log4r::Logger.new

works. thanks.
Brian C. (Guest)
on 2009-01-21 12:48
Zhao Yi wrote:
> Ryan D. wrote:
>> On Jan 20, 2009, at 17:11 , Zhao Yi wrote:
>>
>>> I require two ruby files which include two classes with the same name.
>>> how can I specify which class I use?
>>
>> class X; end # x.rb
>> class X; end # y.rb
>>
>> same class, only one to specify. Files mean nothing in ruby, they're
>> just vehicles for the parser.
>
> For this code:
>
> require 'x.rb'
> require 'y.rb'
> X.new     #which class it uses, can I specify the class like x.X or y.X?

Nope - there is only one class X. Which file it was (first) defined in
makes no difference. If you require 'x.rb' first then class X is
created, and when you require 'y.rb' new methods are added into the
*same* class.

If you want them to be different, define them in different namespaces.
This is what Log4r:: does (it refers to the namespace, not the file)

module One; class X; end; end    # x.rb
module Two; class X; end; end    # y.rb

require 'x'
require 'y'
One::X.new   # this is the one defined in x.rb
Two::X.new   # this is the one defined in y.rb
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