* datatype.js: some design changes

datatype.js

@@ -1,60 +1,75 @@
 (function() {
 
-var multiMap = {};
+  var multiMap = {};
+  function Type() {};
+  function Protocol() {};
+
+  _.mixin({
+    extenderOf: function(x, protocol) {
+      return _(x.protocols).indexOf(protocol) != -1;
+    },
+
+    Multi: function(name, type, fn) {
+      if(_.isUndefined(multiMap[name])) {
+        var dispatchTable = {},
+            dispatcher = {};
+        multiMap[name] = dispatchTable;
+        dispatcher[name] = function(instance) {
+          var rest = _.rest(arguments);
+          return multiMap[name][instance.name].apply(instance, rest);
+        };
+        _.mixin(dispatcher);
+      }
+      multiMap[name][type.name] = fn;
+    },
 
-_.mixin({
-  extenderOf: function(x, protocol) {
-    return _(x.protocols).indexOf(protocol) != -1;
-  },
+    isProtocol: function() {
+      return x instanceof Protocol;
+    },
 
-  multi: function(name, type, fn) {
-    if(_.isUndefined(multiMap[name])) {
-      var dispatchTable = {};
-      multiMap[name] = dispatchTable;
-      var dispatcher = {};
-      dispatcher[name] = function(instance) {
-        var rest = _.rest(arguments);
-        return multiMap[name][instance.name].apply(instance, rest);
+    Protocol: function(obj) {
+      obj.prototype = new Protocol;
+      obj.toString = function() {
+        return ["<Protocol: ", (obj.name || _uniqueId("UnnamedProtocol")), ">"].join("");
       };
-      _.mixin(dispatcher);
-    }
-    multiMap[name][type.name] = fn;
-  },
+      return obj;
+    },
+
+    isType: function(x) {
+      return x instanceof Type;
+    },
 
-  protocol: function(obj) {
-    obj.toString = function() {
-      return ["<Protocol: ", (obj.name || _uniqueId("UnnamedProtocol")), ">"].join("");
-    };
-    return obj;
-  },
-
-  datatype: function(obj) {
-    obj = obj || {};
-    var klass = function() {
-      if(_.isFunction(this.initialize)) {
-        return this.initialize.apply(this, arguments);
-      } else {
-        return this;
-      }
-    };
-    var protocols = obj.protocols || [];
-    var name = obj.name = (obj.name || _.uniqueId("UnnamedType"));
-    var methodMap = protocols
-      .map(function(x) { x = _(x).clone(); delete x.name; delete x.toString; return x; });
-    obj =_.reduce(methodMap.concat(obj), {}, function(memo, m) {
-      return _.extend(memo, m);
-    });
-    obj = _(obj).extend({
-      toString: function() {
-        return ["<Type: ", name, ">"].join("");
-      }
-    });
-    klass.name = name;
-    klass.prototype = obj;
-    klass.prototype.type = klass;
-    klass.prototype.protocols = klass.protocols = protocols;
-    return klass;
-  }
-});
+    Type: function(obj) {
+      obj = obj || {};
+      var klass = function() {
+        if(_.isFunction(this.initialize)) {
+          return this.initialize.apply(this, arguments);
+        } else {
+          return this;
+        }
+      };
+      var protocols = obj.protocols || [],
+          name = obj.name = (obj.name || _.uniqueId("UnnamedType")),
+          methodMap = protocols.map(function(x) {
+            x = _(x).clone(); delete x.name; delete x.toString; return x;
+          });
+      obj =_.reduce(methodMap.concat(obj), {}, function(memo, m) {
+        return _.extend(memo, m);
+      });
+      obj = _(obj).extend({
+        toString: function() {
+          return ["<Type: ", name, ">"].join("");
+        }
+      });
+      klass.name = name;
+      klass.prototype = new Type();
+      klass.prototype.type = klass;
+      klass.prototype.protocols = klass.protocols = protocols;
+      _(obj).each(function(v, k) {
+        klass.prototype[k] = v;
+      });
+      return klass;
+    }
+  });
 
 })();