Cleaned Code

MathPad/MPExpression.m

@@ -308,10 +308,7 @@
             break;
             
         case MPTokenReferenceFrame:
-            [_elements enumerateObjectsUsingBlock:^(id<MPToken> obj, NSUInteger idx, BOOL *stop) {
-                symbolIndex = NSMaxRange(obj.range);
-                *stop = idx >= index - 1;
-            }];
+            symbolIndex = [self.tokens[index] range].location;
             break;
     }
     
@@ -345,22 +342,24 @@
             
         case MPTokenReferenceFrame:
         {
-            NSUInteger totalLength = 0;
             NSUInteger tokenIndex = 0;
-            id<MPToken> token;
-            while (totalLength < symbolIndex) {
-                token = self.tokens[tokenIndex++];
-                totalLength = NSMaxRange(token.range);
+            while (true) {
+                id<MPToken> token = self.tokens[tokenIndex++];
+                if (NSMaxRange(token.range) < symbolIndex || token.range.location > symbolIndex) {
+                    continue;
+                }
+                NSUInteger offsetInToken = index - token.range.location;
+                if (offsetInToken == token.range.length) {
+                    offsetInToken = 0;
+                    tokenIndex++;
+                }
+                if (offset) {
+                    *offset = offsetInToken;
+                }
+                return tokenIndex;
             }
-            NSUInteger offsetInToken = token.range.length - totalLength + symbolIndex;
-            if (offsetInToken == token.range.length) {
-                offsetInToken = 0;
-                tokenIndex++;
-            }
-            if (offset) {
-                *offset = offsetInToken;
-            }
-            return tokenIndex;
+            // Should never get here
+            return 0;
         }
     }
 }
@@ -525,15 +524,10 @@
 - (NSDecimalNumber *)evaluateWithError:(MPParseError *__autoreleasing *)error
 {
     MPExpressionTree *tree = [self parse];
-    if ([tree validate:error]) {
-        return [tree evaluate];
-    }
-    if (error) {
-        (*error).pathToExpression = self.indexPath;
-    }
-    return nil;
+    return [tree validate:error] ? [tree evaluate] : nil;
 }
 
+
 - (MPExpressionTree *)parse
 {
     MPTokenStream *tokenStream = [[MPTokenStream alloc] initWithTokens:self.tokens];