Cleaned Code & Fixed Some Errors

MathPad/MPFractionTerm.m

@@ -14,16 +14,18 @@
 
 - (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error
 {
-    NSDecimalNumber *nominator = [[self expressionAtIndex:0] evaluate:error];
-    if (!nominator) {
+    MPEvaluateExpression(nominator, 0);
+    MPEvaluateExpression(denominator, 1);
+    if ([denominator isEqualToNumber:@0]) {
+        if (error) {
+            *error = [NSError errorWithDomain:MPMathKitErrorDomain
+                                         code:100
+                                     userInfo:@{NSLocalizedDescriptionKey: NSLocalizedString(@"Division by zero.", nil)}];
+        }
         return nil;
+    } else {
+        return [nominator decimalNumberByDividingBy:denominator];
     }
-    NSDecimalNumber *denominator = [[self expressionAtIndex:1] evaluate:error];
-    if (!denominator) {
-        return nil;
-    }
-#warning Division by zero ahead
-    return [nominator decimalNumberByDividingBy:denominator];
 }
 
 @end