Merge pull request #176 from v-for-vandal/lua_eq

Add default __eq implementation for Lua

Examples/test-suite/lua/cpp_basic_runme.lua

@@ -86,3 +86,14 @@ f4_name = tostring(f4)
 assert( f2_name == "Foo" )
 assert( f3_name == "Foo" )
 assert( f4_name == "FooSubSub" )
+
+-- Test __eq implementation supplied by default
+
+-- eq_f1 and eq_f2 must be different userdata with same Foo* pointer. If eq_f1 and eq_f2 are the same userdata (e.g.)
+-- > eq_f1 = smth
+-- > eq_f2 = eq_f1
+-- then default Lua equality comparison kicks in and considers them equal. Access to global_fptr is actually a
+-- function call (internally) and it returns new userdata each time.
+eq_f1 = cb.Bar.global_fptr
+eq_f2 = cb.Bar.global_fptr
+assert( eq_f1 == eq_f2 )

Examples/test-suite/lua/equality_runme.lua

@@ -0,0 +1,47 @@
+require("import")	-- the import fn
+import("equality")	-- import code
+eq=equality    -- renaming import
+
+-- catch "undefined" global variables
+local env = _ENV -- Lua 5.2
+if not env then env = getfenv () end -- Lua 5.1
+setmetatable(env, {__index=function (t,i) error("undefined global variable `"..i.."'",2) end})
+
+-- === No equality operator ===
+
+-- logically same data without equality operator are not equal
+p1 = eq.MakePoint(10,9);
+p2 = eq.MakePoint(10,9);
+
+assert( p1 ~= p2 );
+
+-- different wrappers for same Point* are equal
+p3 = eq.GetZeroPointPtr()
+p4 = eq.GetZeroPointPtr()
+
+assert( p3 == p4 )
+
+
+-- === Logically correct equality operator ===
+
+ed1 = eq.EqualOpDefined(10)
+ed2 = eq.EqualOpDefined(10)
+ed3 = eq.EqualOpDefined(15)
+
+assert( ed1 == ed2 )
+assert( ed1 ~= ed3 )
+
+
+-- === Logically incorrect equality operator ===
+
+ew1 = eq.EqualOpWrong()
+ew2 = eq.EqualOpWrong()
+
+assert( ew1 ~= ew2 );
+
+ew3 = eq.EqualOpWrong.GetStaticObject()
+ew4 = eq.EqualOpWrong.GetStaticObject()
+
+-- Even though these are pointers to same object, operator== overload should
+-- state that they are not equal
+assert( ew3 ~= ew4 )