From 3f915d36449ad43030d7e0691905595f07954ee5 Mon Sep 17 00:00:00 2001
From: Mike Gerwitz <mike@mikegerwitz.com>
Date: Thu, 3 Mar 2011 19:08:24 -0500
Subject: [PATCH] The interface module may now be invoked, providing a more
 natural looking means of declaring interfaces

---
 lib/interface.js              |  39 ++++++++-
 test/test-interface-extend.js | 146 +++++++++++++++++++++++-----------
 2 files changed, 139 insertions(+), 46 deletions(-)

diff --git a/lib/interface.js b/lib/interface.js
index 7958c80..f9098f4 100644
--- a/lib/interface.js
+++ b/lib/interface.js
@@ -27,12 +27,49 @@ var util           = require( './util' ),
     Class          = require( './class' );
 
 
+/**
+ * This module may be invoked in order to provide a more natural looking
+ * interface definition
+ *
+ * Only new interfaces may be created using this method. They cannot be
+ * extended. To extend an existing interface, call its extend() method, or use
+ * the extend() method of this module.
+ *
+ * @param  {Object}  def  interface definition
+ *
+ * @return  {Interface}  new interface
+ */
+module.exports = function( def )
+{
+    // if the first argument is an object, then we are declaring an interface
+    if ( typeof def !== 'object' )
+    {
+        throw TypeError(
+            "Must provide interface definition when declaring interface"
+        );
+    }
+
+    // ensure we have the proper number of arguments (if they passed in too
+    // many, it may signify that they don't know what they're doing, and likely
+    // they're not getting the result they're looking for)
+    if ( arguments.length > 1 )
+    {
+        throw Error(
+            "Expecting one argument for Interface definition; " +
+                arguments.length + " given."
+        );
+    }
+
+    return extend( def );
+};
+
+
 /**
  * Creates an interface
  *
  * @return  {Interface}  extended interface
  */
-exports.extend = function()
+module.exports.extend = function()
 {
     return extend.apply( this, arguments );
 };
diff --git a/test/test-interface-extend.js b/test/test-interface-extend.js
index 385fe7c..06d68e7 100644
--- a/test/test-interface-extend.js
+++ b/test/test-interface-extend.js
@@ -83,57 +83,113 @@ assert.doesNotThrow(
 );
 
 
-var BaseType = Interface.extend(
+// There's a couple ways to create interfaces. Test 'em both.
+var base_types = [
+    Interface.extend(
+    {
+        'abstract method': [],
+    } ),
+
+    Interface( {
+        'abstract method': [],
+    } )
+];
+
+var BaseType;
+for ( var i = 0; i < base_types.length; i++ )
 {
-    'abstract method': [],
-});
+    BaseType = base_types[ i ];
 
-assert.ok(
-    ( BaseType.prototype.method instanceof Function ),
-    "Interface contains defined abstract methods"
-);
+    assert.ok(
+        ( BaseType.prototype.method instanceof Function ),
+        "Interface contains defined abstract methods"
+    );
 
 
-var SubType = Interface.extend( BaseType,
+    var SubType = Interface.extend( BaseType,
+    {
+        'abstract second': [],
+    });
+
+    assert.ok(
+        ( SubType.prototype instanceof BaseType ),
+        "Generic interface extend method can extend from other interfaces"
+    );
+
+    assert.ok(
+        ( SubType.prototype.method === BaseType.prototype.method ),
+        "Interface subtypes inherit abstract methods"
+    );
+
+    assert.ok(
+        ( SubType.prototype.second instanceof Function ),
+        "Interfaces can be extended with additional abstract methods"
+    );
+
+
+    assert.ok(
+        ( BaseType.extend instanceof Function ),
+        "Interface contains extend method"
+    );
+
+
+    var SubType2 = BaseType.extend(
+    {
+        'abstract second': [],
+    });
+
+    assert.ok(
+        ( SubType2.prototype instanceof BaseType ),
+        "Interface extend method can extend interfaces"
+    );
+
+    assert.ok(
+        ( SubType2.prototype.second instanceof Function ),
+        "Interfaces can be extended with additional abstract methods using " +
+            "shorthand extend method"
+    );
+}
+
+
+/**
+ * The interface invocation action depends on what arguments are passed in. One
+ * use is to pass in an object as the first and only argument, creating a new
+ * interface with no supertype.
+ */
+( function testInvokingInterfaceModuleRequiresObjectAsArgumentIfExtending()
 {
-    'abstract second': [],
-});
+    assert.throws( function()
+        {
+            Interface( 'moo' );
+            Interface( 5 );
+            Interface( false );
+            Interface();
+        },
+        TypeError,
+        "Invoking interface module requires object as argument if extending " +
+            "from base interface"
+    );
 
-assert.ok(
-    ( SubType.prototype instanceof BaseType ),
-    "Generic interface extend method can extend from other interfaces"
-);
+    var args = [ {}, 'one', 'two', 'three' ];
 
-assert.ok(
-    ( SubType.prototype.method === BaseType.prototype.method ),
-    "Interface subtypes inherit abstract methods"
-);
+    // we must only provide one argument if the first argument is an object (the
+    // interface definition)
+    try
+    {
+        Interface.apply( null, args );
 
-assert.ok(
-    ( SubType.prototype.second instanceof Function ),
-    "Interfaces can be extended with additional abstract methods"
-);
-
-
-assert.ok(
-    ( BaseType.extend instanceof Function ),
-    "Interface contains extend method"
-);
-
-
-var SubType2 = BaseType.extend(
-{
-    'abstract second': [],
-});
-
-assert.ok(
-    ( SubType2.prototype instanceof BaseType ),
-    "Interface extend method can extend interfaces"
-);
-
-assert.ok(
-    ( SubType2.prototype.second instanceof Function ),
-    "Interfaces can be extended with additional abstract methods using " +
-        "shorthand extend method"
-);
+        // if all goes well, we don't get to this line
+        assert.fail(
+            "Only one argument for interface definitions is permitted"
+        );
+    }
+    catch ( e )
+    {
+        assert.notEqual(
+            e.toString().match( args.length + ' given' ),
+            null,
+            "Interface invocation should give argument count on error"
+        );
+    }
+} )();