gistfile1.rb

require 'set'

module Styx
    class Interface
        attr_reader :methods

        def initialize
            @methods = {}
        end
    end

    class Struct
        attr_reader :fields

        def initialize
            @fields = {}
        end
    end

    class Method
        attr_reader :parameters

        def initialize(parameters)
            @parameters = parameters
        end
    end

    class MethodImplementation
        attr_reader :method, :parameter_types

        def initialize(method, parameter_types)
            @method = method
            @parameter_types = parameter_types
        end
    end

    class Context
        attr_accessor :interfaces, :structs, :methods

        def initialize
            @interfaces = Set.new
            @structs = Set.new
            @methods = {}
        end

        def implements_interface?(struct, interface)
            interface.methods.all? do |[method, param_types]|
                expected_param_types = param_types.map{ |param_type| param_type || struct }
                @methods[method].include? expected_param_types
            end
        end

        def implementing_structs(interface)
            @structs.filter{ |struct| implements?(struct, interface) }
        end
    end
end