Fundamental Redesign of Evaluation

MathPad/MPParenthesisFunction.m

@@ -10,7 +10,7 @@
 #import "MPParenthesisFunction.h"
 
 #import "MPExpression.h"
-#import "MPExpressionTree.h"
+#import "MPParenthesisTerm.h"
 
 @implementation MPParenthesisFunction
 
@@ -21,14 +21,9 @@ MPFunctionAccessorImplementation(Expression, _expression)
     return @[@"expression"];
 }
 
-- (BOOL)validate:(NSError *__autoreleasing *)error
+- (Class)functionTermClass
 {
-    return [[self.expression parse] validate:error];
-}
-
-- (NSDecimalNumber *)evaluate
-{
-    return [[self.expression parse] evaluate];
+    return [MPParenthesisTerm class];
 }
 
 - (NSString *)description