# How do you create a large number of irb commands?

**URL:** <https://www.ruby-forum.com/t/how-do-you-create-a-large-number-of-irb-commands/167888>\
**Category:** Ruby\
**Created:** [May 13, 2009, 5:11pm UTC](https://www.ruby-forum.com/t/how-do-you-create-a-large-number-of-irb-commands/167888 "2009-05-13T17:11:01Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![ghorner](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/a183cd/32.png) [@ghorner](https://www.ruby-forum.com/u/ghorner)\
**Post date:** [May 13, 2009, 5:11pm UTC](https://www.ruby-forum.com/t/how-do-you-create-a-large-number-of-irb-commands/167888/1 "2009-05-13T17:11:01Z")

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I’m wondering what you all consider the best way for creating a large  
number of irb commands. By commands I’m referring to methods for the  
default irb object like irb,fg and jobs. Here are some of the  
different ways that come to mind:

- Extend the default irb object with modules.
- Include modules into the default irb object. However this has the  
nasty side effect of making those methods accessible to all objects.
- Just define methods in the default irb object. Simple and seems to  
be the common way in irbrc’s.
- Use irb’s internal command system i.e. self.def\_extend\_command() in  
[http://github.com/rubyspec/matzruby/blob/9ca4e66f27e2563512afdd4c70afab34d80d513d/lib/irb/extend-command.rb](http://github.com/rubyspec/matzruby/blob/9ca4e66f27e2563512afdd4c70afab34d80d513d/lib/irb/extend-command.rb)  
Seems like overkill.

To me the only serious options are extending or just defining the  
method. By extending I get an ancestry trace on where commands came  
from which is important when dealing with a large number of commands.  
Also, if i do switch subsessions or workspaces I can just extend in  
needed functionality. Since defining methods in the irb object lacks  
the ancestry trace and the ability to reuse them in other context, my  
vote is for extending.

Thoughts?

Gabriel

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**Author:** ![ghorner](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/a183cd/32.png) [@ghorner](https://www.ruby-forum.com/u/ghorner)\
**Post date:** [May 13, 2009, 5:51pm UTC](https://www.ruby-forum.com/t/how-do-you-create-a-large-number-of-irb-commands/167888/2 "2009-05-13T17:51:01Z")

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On May 13, 11:07 am, ghorner [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> - Use irb’s internal command system i.e. self.def\_extend\_command() inhttp://github.com/rubyspec/matzruby/blob/9ca4e66f27e2563512afdd4c70af…  
> Thoughts?
> 
> Gabriel

I forgot to mention the option of commands as private methods in  
Kernel space. Like the include option, I think it’s too dirty as it  
gives all objects access to those methods through send(). Although  
this doesn’t matter for a couple of commands, it could lead to some  
dangerous side effects for many commands. My vote is still with  
extending modules.

Gabriel

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**Author:** ![ghorner](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/a183cd/32.png) [@ghorner](https://www.ruby-forum.com/u/ghorner)\
**Post date:** [May 15, 2009, 12:05am UTC](https://www.ruby-forum.com/t/how-do-you-create-a-large-number-of-irb-commands/167888/3 "2009-05-15T00:05:30Z")

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On May 13, 11:49 am, cldwalker [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> > - Include modules into the default irb object. However this has the  
> > needed functionality. Since defining methods in the irb object lacks  
> > this doesn’t matter for a couple of commands, it could lead to some  
> > dangerous side effects for many commands. My vote is still with  
> > extending modules.
> 
> Gabriel

So I guess _no one_ creates commands in irb?