# Unable to register constants

**URL:** <https://www.ruby-forum.com/t/unable-to-register-constants/69242>\
**Category:** Ruby\
**Created:** [September 19, 2006, 5:10pm UTC](https://www.ruby-forum.com/t/unable-to-register-constants/69242 "2006-09-19T17:10:58Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![mjgp2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/eb8c5e/32.png) [@mjgp2](https://www.ruby-forum.com/u/mjgp2)\
**Post date:** [September 19, 2006, 5:10pm UTC](https://www.ruby-forum.com/t/unable-to-register-constants/69242/1 "2006-09-19T17:10:58Z")

</div>

Hi guys… not sure why setting constants here isn’t working!?! Here’s  
the code:

class Module

```
@@dynamically_created_models ||= Hash.new

alias :normal_const_missing :const_missing

def const_missing(class_id)

  begin
    return normal_const_missing(class_id)
  rescue
  end

  puts "Looking for unintialized model #{class_id}"

  if @@dynamically_created_models[class_id]
    puts "*** Constant not set correctly, getting from class 

```

variable…"  
return @@dynamically\_created\_models[class\_id]  
end

```
  # Can we auto generate this model class?
  unless table_name = DrNicMagicModels::Schema.models[class_id]
    raise NameError.new("uninitialized constant #{class_id}")
  end

  klass = Class.new(ActiveRecord::Base)
  klass.class_eval do
    set_table_name table_name
  end

  @@dynamically_created_models[class_id] = klass
  const_set class_id, klass

  return const_get(class_id) rescue raise("Cannot set constant 

```

#{class\_id}")  
end

end

Sure enough, when i run a small test program, part of the output is:

Looking for unintialized model Group  
\*\*\* Constant not set correctly, getting from class variable…

Any help gratefully received!

Thanks,

Matt

---

<div class="post-metadata">

**Author:** ![mjgp2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/eb8c5e/32.png) [@mjgp2](https://www.ruby-forum.com/u/mjgp2)\
**Post date:** [September 20, 2006, 10:12am UTC](https://www.ruby-forum.com/t/unable-to-register-constants/69242/2 "2006-09-20T10:12:08Z")

</div>

Matthew P. schrieb:

> Hi guys… not sure why setting constants here isn’t working!?! Here’s  
> the code:
> 
> (…)
> 
> Sure enough, when i run a small test program, part of the output is:
> 
> Looking for unintialized model Group  
> \*\*\* Constant not set correctly, getting from class variable…

Matt, your code (minus the Rails dependencies) did work for me with a  
very simple test case. Could you show us your test program?

Regards,  
Pit