# How to understand Ruby code? (noting various mixins/includes) Is there a tool to assist here?

**URL:** <https://www.ruby-forum.com/t/how-to-understand-ruby-code-noting-various-mixins-includes-is-there-a-tool-to-assist-here/179915>\
**Category:** Ruby\
**Created:** [December 8, 2009, 12:47am UTC](https://www.ruby-forum.com/t/how-to-understand-ruby-code-noting-various-mixins-includes-is-there-a-tool-to-assist-here/179915 "2009-12-08T00:47:41Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![greg](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/71c47a/32.png) [@greg](https://www.ruby-forum.com/u/greg)\
**Post date:** [December 8, 2009, 12:47am UTC](https://www.ruby-forum.com/t/how-to-understand-ruby-code-noting-various-mixins-includes-is-there-a-tool-to-assist-here/179915/1 "2009-12-08T00:47:41Z")

</div>

Hi,

I seem to spend a good deal of time trying to make sense of open  
source ruby code due to the way it is very dynamic. There are various  
code files that are really just ready to be “mixed in” to other files  
(e.g. with the class methods & instance methods ready to go). Just  
trying to make sense of the final object structure and where methods  
resides seems to be a challenge. The latest one I’ve been looking at  
are things like AuthLogic and Paperclip which are used in the Rails  
world.

QUESTION 1: Is there a tool that could assist here? I’m thinking of  
one that could do things like walk the code base and then:

- Give a hierarchy structure where various files methods are loaded  
into which objects

- Perhaps something that analyses code and then added comments to  
the various files highlighting where that files methods will reside in  
terms of the final object structure.

- Given sample walk throughs of methods hit in which files for a  
given use case (e.g. like how the java IDEs can auto-sequence  
diagrams)

QUESTION 2: Should of nothing be available for the above, and tips/  
tricks people have re understanding a new ruby codebase? (although in  
particular with a rails bent)

thanks

---

<div class="post-metadata">

**Author:** ![greg](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/71c47a/32.png) [@greg](https://www.ruby-forum.com/u/greg)\
**Post date:** [December 8, 2009, 1:16am UTC](https://www.ruby-forum.com/t/how-to-understand-ruby-code-noting-various-mixins-includes-is-there-a-tool-to-assist-here/179915/2 "2009-12-08T01:16:22Z")

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On Mon, Dec 7, 2009 at 4:47 PM, Greg H. \<  
removed\_email\_address@domain.invalid\> wrote:

> Just trying to make sense of the final object structure and where methods  
> resides seems to be a challenge. The latest one I’ve been looking at  
> are things like AuthLogic and Paperclip which are used in the Rails  
> world.

I feel your pain, especially with AuthLogic. It’s very difficult to  
follow  
how methods are dispatched among a quagmire of mixins.

---

<div class="post-metadata">

**Author:** ![greg](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/71c47a/32.png) [@greg](https://www.ruby-forum.com/u/greg)\
**Post date:** [December 8, 2009, 1:56am UTC](https://www.ruby-forum.com/t/how-to-understand-ruby-code-noting-various-mixins-includes-is-there-a-tool-to-assist-here/179915/3 "2009-12-08T01:56:47Z")

</div>

On Dec 7, 2009, at 8:45 PM, Tony A. wrote:

> I feel your pain, especially with AuthLogic. It’s very difficult to  
> follow  
> how methods are dispatched among a quagmire of mixins.

I found that YARD does a good job at finding static relationships  
between classes  
as well as informing you about them. It also provides a tool that  
draws you a graph  
out of them (yard-graph).

For a sample: [http://yardoc.org/docs/datamapper-dm-core/DataMapper/](http://yardoc.org/docs/datamapper-dm-core/DataMapper/)  
Model (includes  
2 modules, extends another one, is defined in more then one file and  
defines multiple  
helper classes and modules under his namespace.

It’s not 100%, but catches most reasonable cases. For more gathering,  
there is still  
Kernel#set\_trace\_fun. I experimented with a visualization for that for  
university,  
but it explodes horribly quick.

Regards,  
Florian G.

---

<div class="post-metadata">

**Author:** ![greg](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/71c47a/32.png) [@greg](https://www.ruby-forum.com/u/greg)\
**Post date:** [December 8, 2009, 2:28am UTC](https://www.ruby-forum.com/t/how-to-understand-ruby-code-noting-various-mixins-includes-is-there-a-tool-to-assist-here/179915/4 "2009-12-08T02:28:58Z")

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On Monday 07 December 2009 05:47:11 pm Greg H. wrote:

> QUESTION 1: Is there a tool that could assist here?

Probably. I know people have written tools which generate Graphviz  
charts of  
whole programs. I haven’t used these tools, though, especially when  
there’s  
decent documentation – so listen to the other posters on this one.

> - Given sample walk throughs of methods hit in which files for a  
> given use case (e.g. like how the java IDEs can auto-sequence  
> diagrams)

I don’t really know what this looks like. Ruby does have a debugger, but  
as  
you’ve used a Java IDE before, I assume the concept of a debugger isn’t  
new to  
you.

> QUESTION 2: Should of nothing be available for the above, and tips/  
> tricks people have re understanding a new ruby codebase? (although in  
> particular with a rails bent)

Well, there’s always playing around in irb – or script/console, in  
Rails.  
There’s inserting puts and p statements into the code – with a local  
branch,  
obviously, so you can revert those.

The best tool, though, is good documentation, and especially, read the  
specs,  
or the tests. Rails seems to be trying to strongly encourage TDD, which  
means  
that every intended behavior should have a descriptively-named test for  
it.  
This will at least give you an idea of how the code is intended to be  
used,  
and that’s the very first thing you’ll need before trying to understand  
how it  
works.

---

<div class="post-metadata">

**Author:** ![greg](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/71c47a/32.png) [@greg](https://www.ruby-forum.com/u/greg)\
**Post date:** [December 8, 2009, 7:22pm UTC](https://www.ruby-forum.com/t/how-to-understand-ruby-code-noting-various-mixins-includes-is-there-a-tool-to-assist-here/179915/5 "2009-12-08T19:22:08Z")

</div>

thanks for the pointer to YARD - interestingly I just run across my  
whole rails app (which has AuthLogic as a plugin), but it did give  
some WARNINGS and finally an exception - I’ll have a better look

e.g.  
[warn]: in YARD::Handlers::Ruby::Legacy::ClassHandler: Undocumentable  
class ‘base’  
[warn]: in file  
‘./vendor/plugins/redhillonrails\_core/lib/red\_hill\_consulting/core/active\_record/schema.rb’:9:

```
    9: class << base
    10: attr_accessor :defining
    11: alias :defining? :defining
    12:
    13: alias_method_chain :define, :redhillonrails_core
    14: end

```

/opt/local/lib/ruby/gems/1.8/gems/yard-0.4.0/templates/default/module/html/defines.erb:2:in  
`erb': wrong argument type Symbol (expected Proc) (TypeError) from /opt/local/lib/ruby/gems/1.8/gems/yard-0.4.0/bin/../lib/yard/templates/template.rb:225:in `erb’  
from  
/opt/local/lib/ruby/gems/1.8/gems/yard-0.4.0/templates/default/module/html/box\_info.erb:28:in  
`erb' from /opt/local/lib/ruby/gems/1.8/gems/yard-0.4.0/bin/../lib/yard/templates/template.rb:225:in `erb’  
from  
/opt/local/lib/ruby/gems/1.8/gems/yard-0.4.0/bin/…/lib/yard/templates/template.rb:306:in  
`render_section' from /opt/local/lib/ruby/gems/1.8/gems/yard-0.4.0/bin/../lib/yard/templates/template.rb:196:in `run’  
from /opt/local/lib/ruby/1.8/erb.rb:743:in `each_with_index' from /opt/local/lib/ruby/gems/1.8/gems/yard-0.4.0/bin/../lib/yard/templates/template.rb:191:in `each’  
from  
/opt/local/lib/ruby/gems/1.8/gems/yard-0.4.0/bin/…/lib/yard/templates/template.rb:191:in  
`each_with_index' ... 38 levels... from /opt/local/lib/ruby/gems/1.8/gems/yard-0.4.0/bin/../lib/yard/cli/yardoc.rb:29:in `run’  
from /opt/local/lib/ruby/gems/1.8/gems/yard-0.4.0/bin/yardoc:4  
from /opt/local/bin/yardoc:19:

2009/12/8 Florian G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):