# Get namespaces
**URL:** https://rubytalk.org/t/get-namespaces/73873
**Category:** ruby-talk
**Created:** [4 November 2016 14:52 UTC](https://rubytalk.org/t/get-namespaces/73873 "2016-11-04T14:52:34Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@Die\_Optimisten](https://rubytalk.org/u/Die_Optimisten)
#### Post date: [4 November 2016 14:52 UTC](https://rubytalk.org/t/get-namespaces/73873/1 "2016-11-04T14:52:34Z")
Hi
Is there a method to get all namespaces (like Math::, which don't have to be loaded necessarily)
Opti
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### Author:  [@Rob\_Biedenharn](https://rubytalk.org/u/Rob_Biedenharn)
#### Post date: [4 November 2016 15:11 UTC](https://rubytalk.org/t/get-namespaces/73873/2 "2016-11-04T15:11:37Z")
Hi
Is there a method to get all namespaces (like Math::, which don't have
to be loaded necessarily)
Opti
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Perhaps something like:
Object.constants.map{|c| eval c.to\_s }.select{|o| o.is\_a?(Module) && !
o.is\_a?(Class) }
Would be a start.
-Rob
> **···**
>
> On Fri, Nov 4, 2016 at 10:52 AM Die Optimisten \<[inform@die-optimisten.net](mailto:inform@die-optimisten.net)\> wrote:
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### Author:  [@Xavier\_Noria](https://rubytalk.org/u/Xavier_Noria)
#### Post date: [4 November 2016 15:15 UTC](https://rubytalk.org/t/get-namespaces/73873/3 "2016-11-04T15:15:10Z")
which don't have to be loaded necessarily
>
What do you mean there? And what is the program supposed to have loaded at
that point?
> **···**
>
> On Fri, Nov 4, 2016 at 3:52 PM, Die Optimisten \ wrote:
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### Author:  [@Robert\_K1](https://rubytalk.org/u/Robert_K1)
#### Post date: [4 November 2016 16:34 UTC](https://rubytalk.org/t/get-namespaces/73873/4 "2016-11-04T16:34:23Z")
I think that requirement is impossible to fulfill since with
autoloading and other features you cannot know what files can be
loaded potentially to determine all possible namespaces.
You can determine all currently known namespaces though:
puts ObjectSpace.each\_object(Module).to\_a
puts ObjectSpace.each\_object(Module).sort\_by {|x| x.name || ""}
Kind regards
robert
> **···**
>
> On Fri, Nov 4, 2016 at 4:15 PM, Xavier Noria \ wrote:
>
> > On Fri, Nov 4, 2016 at 3:52 PM, Die Optimisten \ \> wrote:
> >
> > > which don't have to be loaded necessarily
> >
> > What do you mean there? And what is the program supposed to have loaded at
> > that point?
>
> --
> [guy, jim, charlie].each {|him| remember.him do |as, often| as.you\_can
> - without end}
> [http://blog.rubybestpractices.com/](http://blog.rubybestpractices.com/)
---
### Author:  [@Die\_Optimisten](https://rubytalk.org/u/Die_Optimisten)
#### Post date: [4 November 2016 22:04 UTC](https://rubytalk.org/t/get-namespaces/73873/5 "2016-11-04T22:04:45Z")
Thank you Robert!
What Modul is 'fatal ' (lowercase??)
Opti
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### Author:  [@Die\_Optimisten](https://rubytalk.org/u/Die_Optimisten)
#### Post date: [4 November 2016 23:03 UTC](https://rubytalk.org/t/get-namespaces/73873/6 "2016-11-04T23:03:56Z")
Hi
How can I select the main-class, if I have more Modules using the same name for a class?
e.g.:
String
Neither "abc".A:🅱:String.to\_s nor
"abc".Main::String.to\_s is working!
Thank you
Opti
> **···**
>
> A:🅱:String
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### Author:  [@Xavier\_Noria](https://rubytalk.org/u/Xavier_Noria)
#### Post date: [4 November 2016 23:32 UTC](https://rubytalk.org/t/get-namespaces/73873/7 "2016-11-04T23:32:23Z")
Maybe I have missed some emails... how do you know the OP is talking about
autoloading?
With the original email, I don't really know which is the situation.
> **···**
>
> On Friday, 4 November 2016, Robert Klemme \ wrote:
>
> > On Fri, Nov 4, 2016 at 4:15 PM, Xavier Noria \ \\> wrote:
> > \> On Fri, Nov 4, 2016 at 3:52 PM, Die Optimisten \< \> inform@die-optimisten.net \\> \> \> wrote:
> > \>
> > \>\> which don't have to be loaded necessarily
> > \>
> > \> What do you mean there? And what is the program supposed to have loaded
> > at
> > \> that point?
> >
> > I think that requirement is impossible to fulfill since with
> > autoloading and other features you cannot know what files can be
> > loaded potentially to determine all possible namespaces.
>
> --
> Sent from Gmail Mobile
---
### Author:  [@Robert\_K1](https://rubytalk.org/u/Robert_K1)
#### Post date: [5 November 2016 11:15 UTC](https://rubytalk.org/t/get-namespaces/73873/8 "2016-11-05T11:15:45Z")
> > \>
> > \>\> which don't have to be loaded necessarily
> > \>
> > \> What do you mean there? And what is the program supposed to have loaded
> > \> at that point?
> >
> > I think that requirement is impossible to fulfill since with
> > autoloading and other features you cannot know what files can be
> > loaded potentially to determine all possible namespaces.
>
> Maybe I have missed some emails... how do you know the OP is talking about
> autoloading?
He was not explicitly. But please look at his sentence I quoted from
the initial question. He is obviously asking for a general mechanism
to obtain all namespaces and explicitly states that he wants also
namespaces which have not been loaded. Autoloading is one mechanism
which might lead to files loaded at an arbitrary point of time.
require is another one and eval yet another one.
> With the original email, I don't really know which is the situation.
There are arbitrary ways that classes and modules can come into
existence at an arbitrary point in time. You could also mention eval.
Thing is, it is fairly easy to get the \_currently known\_ set of
classes and modules but there is no way to look into the future
because of Ruby's dynamic nature.
Kind regards
robert
> **···**
>
> On Sat, Nov 5, 2016 at 12:32 AM, Xavier Noria \ wrote:
>
> > On Friday, 4 November 2016, Robert Klemme \ \> wrote:
> >
> > > On Fri, Nov 4, 2016 at 4:15 PM, Xavier Noria \ wrote:
> > > \> On Fri, Nov 4, 2016 at 3:52 PM, Die Optimisten \>\> \> \ \>\> \> wrote:
>
> --
> [guy, jim, charlie].each {|him| remember.him do |as, often| as.you\_can
> - without end}
> [http://blog.rubybestpractices.com/](http://blog.rubybestpractices.com/)