Fixed Evaluation of Powers and Factorials.

Added Error Messages.

MathPad/MPExpressionParser.m

@@ -371,7 +371,6 @@
                 self.value = term;
             }
         } else if (self.currentToken.tokenType == MPPowerToken) {
-            [self nextToken];
             if (self.value) {
                 NSArray *errors;
                 MPPowerTerm *term = [[MPPowerTerm alloc] initWithFunction:(MPFunction *)self.currentToken errors:&errors];
@@ -381,6 +380,7 @@
                 term.baseTerm = self.value;
                 self.value = term;
             }
+            [self nextToken];
         } else {
             checkMore = NO;
         }
@@ -407,7 +407,12 @@
         if (self.errorTokenIndex >= self.tokens.count) {
             [self addErrorWithCode:0 localizedDescription:NSLocalizedString(@"Unexpected end. Expected Value.", nil)];
         } else {
-            [self addErrorWithCode:1 localizedDescription:NSLocalizedString(@"Unexpected Symbol. Expected Value", nil)];
+            id<MPToken> unexpectedToken = self.tokens[self.errorTokenIndex];
+            if (unexpectedToken.tokenType == MPPowerToken) {
+                [self addErrorWithCode:34 localizedDescription:NSLocalizedString(@"No base for Power", nil)];
+            } else {
+                [self addErrorWithCode:1 localizedDescription:NSLocalizedString(@"Unexpected Symbol. Expected Value", nil)];
+            }
         }
     }
     return self.errors.count > 0;

MathPad/MPFactorialTerm.m

@@ -22,7 +22,7 @@
 
 - (NSDecimalNumber *)doEvaluation:(NSError *__autoreleasing *)error
 {
-    NSDecimalNumber *value = [self.value evaluate:error];
+    NSDecimalNumber *value = [self.term evaluate:error];
     if (!value) {
         return nil;
     }