Can't use Contracts with define_method in a module

[actsasbuffoon]

I love the fact that Contracts works with define_method and define_singleton_method. It makes my life a lot easier. The problem is that the same pattern doesn't seem to work in modules.

require 'contracts'

# This works:
class ExampleClass
  include Contracts

  def self.define_typed_method(method_name)
    # This works, and the contract is applied to the metaprogrammed method
    Contract None => Fixnum
    define_method(method_name) { 42 }
  end

  define_typed_method :foo
end

ExampleClass.new.foo
# => 42

# This is where things go wrong:
module ExampleModule
  include Contracts

  def define_typed_method(method_name)
    Contract None => Fixnum
    # ~> (eval):7:in `Contract': undefined method `Contract' for Class:Class (NoMethodError)
    # ~>    from -:22:in `define_typed_method'
    # ~>    from -:34:in `<class:HypotheticalClass>'
    # ~>    from -:31:in `<main>'
    define_method(method_name) { 42 }
  end
end

class HypotheticalClass
  extend ExampleModule

  # This is how I'd use it, if things were working correctly
  define_typed_method :foo
end

[egonSchiele]

This works for me after I add include Contracts in the HypotheticalClass class, though it should work without that too.

[egonSchiele]

@actsasbuffoon read this comment: https://github.com/egonSchiele/contracts.ruby/issues/229#issuecomment-193544001

I bet this is what is happening here too. Unfortunately the fix won't fix your issue ... Ruby is trying to resolve Contract as a constant, and it doesn't work.

[waterlink]

@egonSchiele Maybe we could provide an alias with lowercase? Like def_contract(...) ?

[egonSchiele]

@waterlink I'm wondering if we should start moving away from Contract and towards contract. This conflict (constant vs function name resolution) will always be there.

[waterlink]

@egonSchiele We can totally do that, I don't mind contract at all. It is not so pretty, but what can you do about it :)