lib/haskell.rb in haskell-0.0.3 vs lib/haskell.rb in haskell-0.1.0

@@ -1,30 +1,49 @@
-require 'haskell/type_list'
-require 'haskell/base'
-require 'haskell/assert_arg_type'
-require 'haskell/assert_rtn_type'
+require 'haskell/type_pair'
 
-module Haskell; end
-
-# New Class(Type)
+# Builtin Contracts
 class  Any;     end
 module Boolean; end
 TrueClass.send(:include, Boolean)
 FalseClass.send(:include, Boolean)
 
 class Module
   private
-    def __haskell__
-      prepend (@__haskell__ = Module.new) unless @__haskell__
-      @__haskell__
+  def __haskell__
+    prepend (@__haskell__ = Module.new) unless @__haskell__
+    @__haskell__
+  end
+
+  def type(*arguments)
+    *arg_types, type_pair, meth = arguments
+
+    __haskell__.send(:define_method, meth) do |*args, &block|
+      ::Haskell.assert_arg_type(meth, args, arg_types << type_pair.last_arg_type)
+      rtn = super(*args, &block)
+      ::Haskell.assert_trn_type(meth, rtn, type_pair.rtn_type)
+      rtn
     end
+    self
+  end
+end
 
-    def type(type_list, meth)
-      __haskell__.send(:define_method, meth) do |*args, &block|
-        ::Haskell::AssertArgType.execute(meth, args, type_list.args)
-        rtn = super(*args, &block)
-        ::Haskell::AssertRtnType.execute(meth, rtn, type_list.rtn)
-        rtn
+module Haskell
+  class << self
+    def assert_arg_type(meth, args, klasses)
+      args.each_with_index do |arg, i|
+        if wrong_type?(arg, klasses[i])
+          raise ArgumentError, "Wrong type of argument, type of #{arg.inspect} should be #{klasses[i]}"
+        end
       end
-      self
     end
+
+    def assert_trn_type(meth, rtn, klass)
+      if wrong_type?(rtn, klass)
+        raise TypeError, "Expected #{meth} to return #{klass} but got #{rtn.inspect} instead"
+      end
+    end
+
+    def wrong_type?(obj, klass)
+      !(obj.is_a?(klass) || klass == Any)
+    end
+  end
 end