ConstLookup

Makes resolving a constant in a given namespace easy.

Installation

Install as usual: gem install const_lookup or add gem 'const_lookup' to your Gemfile. See .travis.yml for supported (tested) Ruby versions.

Usage

module A
  module B; end
  module C; end
end
module D; end

require 'const_lookup'

ConstLookup.lookup('A', A::C)  #=> A
ConstLookup.lookup('B', A::C)  #=> A::B
ConstLookup.lookup('D', A::C)  #=> D
ConstLookup.lookup('E', A::C)  #=> #<NameError: Failed to find `E' in A::C>

Or, if you like monkey-patching Ruby core:

module A
  module B; end
  module C; end
end
module D; end

require 'const_lookup/core_ext'

A::C.const_lookup('B')  #=> A::B
A::C.const_lookup('D')  #=> D

Compare this with using Module#const_get:

module A
  module B; end
  module C; end
end
module D; end

A::C.const_get('A')        #=> A
A::C.const_get('B')        #=> #<NameError: uninitialized constant A::C::B>
A::C.const_get('B', true)  #=> #<NameError: uninitialized constant A::C::B>
A::C.const_get('D')        #=> D
A::C.const_get('E')        #=> #<NameError: uninitialized constant A::C::E>

This is because const_get looks up the ancestor tree, not the namespace tree like ConstLookup does.

Contributing

Contributions are welcome. Please be sure that your pull requests are atomic so they can be considered and accepted separately.

• Fork it
• Create your feature branch (git checkout -b my-new-feature)
• Commit your changes (git commit -am 'Add some feature')
• Push to the branch (git push origin my-new-feature)
• Create new Pull Request

Credits & License

Copyright © 2013–2017 J. Andrew Marshall. License is available in the LICENSE file.