gistfile1.rb

  def self.coerce_rlimit_resource(resource)
    if resource.is_a?(Symbol) && (const_name = "RLIMIT_#{resource}") && const_defined?(const_name)
      resource = const_get(const_name)
    else
      raise ArgumentError, "invalid resource name #{resource}"
    end
    Rubinius::Type.coerce_to resource, Integer, :to_int
  end

This doesn't work, because arguments are allowed to not be Symbols, in which case they should be passed on through to the next step unaltered (ie don't raise).

Maybe something like:

def self.coerce_rlimit_resource(resource)
  if resource.is_a?(Symbol)
   constant_name = "RLIMIT_#{resource}"
   raise ArgumentError, "invalid resource name #{resource}" unless const_defined? constant_name
   resource = const_get constant_name
  end
  Rubinius::Type.coerce_to resource, Integer, :to_int
end

Ah, I see. Yeah, I guess that's a little more concise than initial implementation