Added Factorial, added parts of exponents

MathPad/MPExpressionEvaluator.m

@@ -15,6 +15,7 @@
 #import "MPTokenStream.h"
 
 #import "MPEvaluationContext.h"
+#import "MPPowerFunction.h"
 
 
 
@@ -171,7 +172,7 @@
     switch (token.tokenType) {
         case MPNumberToken:
         {
-            return [[MPTerm alloc] initWithNumber:token.number];
+            return [self decoratedTerm:[[MPTerm alloc] initWithNumber:token.number]];
         }
             
         case MPVariableToken:
@@ -180,12 +181,12 @@
                 self.error = MPParseError(token.range, @"Undefined Variable");
                 return nil;
             }
-            return [[MPTerm alloc] initWithVariable:token.variable];
+            return [self decoratedTerm:[[MPTerm alloc] initWithVariable:token.variable]];
         }
             
         case MPGenericFunctionToken:
         {
-            return [((MPFunction *)token) parseWithError:_error];
+            return [self decoratedTerm:[((MPFunction *)token) parseWithError:_error]];
         }
             
         case MPSinToken:
@@ -241,4 +242,22 @@
     }
 }
 
+- (MPTerm *)decoratedTerm:(MPTerm *)term
+{
+    MPTerm *decoratedTerm = term;
+    MPToken *facultyToken = [tokenStream nextTokenOfType:MPFactorialToken];
+    if (facultyToken) {
+        decoratedTerm = [[MPTerm alloc] initWithFactorialOfTerm:term];
+    }
+    MPToken *powerToken = [tokenStream nextTokenOfType:MPGenericFunctionToken];
+    if ([powerToken isKindOfClass:[MPPowerFunction class]]) {
+        MPPowerFunction *powerFunction = (MPPowerFunction *)powerToken;
+        powerFunction.baseTerm = decoratedTerm;
+        return [powerFunction parseWithError:_error];
+    } else {
+        tokenStream.currentLocation--;
+    }
+    return decoratedTerm;
+}
+
 @end