Implemented hasSameMembers

source/quack/extends.d

@@ -8,7 +8,7 @@ import quack;
  * Checks if Child extends Parent in any of the supported ways.
  *
  * Params:
- *      Child =        The base class to test.
+ *      Child =         The base class to test.
  *      Parent =        The parent class to test.
  *
  * Returns:
@@ -18,7 +18,8 @@ template extends( Child, Parent )
 {
     enum extends =
         is( Child : Parent ) ||
-        isAliasThis!( Child, Parent );
+        isAliasThis!( Child, Parent ) ||
+        hasSameMembers!( Child, Parent );
 }
 ///
 unittest

source/quack/membertest.d

@@ -0,0 +1,77 @@
+/**
+ *
+ */
+module quack.membertest;
+import quack.extends;
+
+import std.algorithm: among;
+
+/**
+ * Checks if Child extends Parent by having a matching set of members.
+ *
+ * Params:
+ *      Child =         The base class to test.
+ *      Parent =        The parent class to test.
+ *
+ * Returns:
+ *      Whether Child has all the members of Parent.
+ */
+template hasSameMembers( Base, Parent )
+{
+    static if( isExtendable!( Base, Parent ) )
+    {
+        enum hasSameMembers = {
+            // If there are no members to check, return false.
+            static if( [__traits( allMembers, Parent )].length == 0 )
+            {
+                return false;
+            }
+            else
+            {
+                foreach( member; __traits( allMembers, Parent ) )
+                {
+                    // Ignore some members.
+                    static if( !member.among( "this" ) )
+                    {
+                        // If Base has the member, check the type.
+                        static if( __traits( hasMember, Base, member ) )
+                        {
+                            static if( !is(
+                                typeof( __traits( getMember, Parent, member ) ) ==
+                                typeof( __traits( getMember, Base, member ) )
+                                ) )
+                            {
+                                return false;
+                            }
+                        }
+                        else
+                        {
+                            return false;
+                        }
+                    }
+                }
+
+                return true;
+            }
+        } ();
+    }
+    else
+    {
+        enum hasSameMembers = false;
+    }
+}
+///
+unittest
+{
+    struct S1
+    {
+        @property int x() { return 42; }
+    }
+
+    struct S2
+    {
+        @property int x() { return 42; }
+    }
+
+    assert( hasSameMembers!( S1, S2 ) );
+}

source/quack/mixins.d

@@ -3,7 +3,7 @@
  * defines all the same members of a template mixin.
  */
 module quack.mixins;
-import quack.extends;
+import quack.extends, quack.membertest;
 
 /**
  *
@@ -12,37 +12,13 @@ template hasTemplateMixin( Base, alias mix )
 {
     static if( isExtendable!Base )
     {
+        //TODO: Make sure `mixin mix!();` compiles.
         private struct MixImpl
         {
-            /*static if( __traits( compiles, mixin mix ) )
-            {*/
-                mixin mix!();
-            //}
+            mixin mix!();
         }
 
-        enum hasTemplateMixin = {
-            bool isEqual = false;
-
-            foreach( member; __traits( allMembers, MixImpl ) )
-            {
-                static if( __traits( hasMember, Base, member ) )
-                {
-                    static if( is(
-                        typeof( __traits( getMember, MixImpl, member ) ) ==
-                        typeof( __traits( getMember, Base, member ) )
-                        ) )
-                    {
-                        isEqual = true;
-                    }
-                }
-                else
-                {
-                    return false;
-                }
-            }
-
-            return isEqual;
-        } ();
+        enum hasTemplateMixin = hasSameMembers!( Base, MixImpl );
     }
     else
     {

source/quack/package.d

@@ -6,3 +6,4 @@ public:
 import quack.extends;
 import quack.aliasthis;
 import quack.mixins;
+import quack.membertest;