Fixed addition and subraction bug in the calc_engine.

calc_engine.py

@@ -146,6 +146,12 @@ def handle_multiply_and_division(tokens):
 	return running_value
 	
 def handle_add_and_subtract(tokens):
+	#
+	# Note: this is should be the first function called to calculate the result of the tokens.
+	# 		A bit hacky, and not the best name for this method, but it grew "orgranically" to be
+	#		this way. For now this is fine, and for what the calc_engine does this may not 
+	#		need to change for the life of this project.
+	#
 	running_value = 0
 	previous_token = token.CToken("", token.TokenType.unknown)
 	
@@ -162,7 +168,7 @@ def handle_add_and_subtract(tokens):
 			
 		if current_token.type == token.TokenType.exp_end:
 			tokens.append(current_token)
-			break
+			break					
 		
 		if current_token.type == token.TokenType.exp_start:
 			running_value = handle_parenthesis(tokens)
@@ -177,11 +183,11 @@ def handle_add_and_subtract(tokens):
 					running_value = operate(previous_token.value, tmp, current_token.type)
 				else:
 					running_value = operate(running_value, tmp, current_token.type)
-					
+				#Set the previous_token to an invalid state so its not used by mistake.
 				previous_token.type = token.TokenType.unknown
 				continue
-			
+				
-			if len(tokens) > 0:
+			elif len(tokens) > 0:
 				two_ahead = peek_list(tokens)
 				
 				if two_ahead.type == token.TokenType.multiply or two_ahead.type == token.TokenType.divide:
@@ -193,14 +199,17 @@ def handle_add_and_subtract(tokens):
 						running_value = operate(previous_token.value, tmp, current_token.type)
 					else:
 						running_value = operate(running_value, tmp, current_token.type)
+					#Set the previous_token to an invalid state so its not used by mistake.
 					previous_token.type = token.TokenType.unknown
+					
+					continue
 			
+			if running_value == 0:
+				running_value = operate(previous_token.value, look_ahead.value, current_token.type)
 			else:
-				if running_value == 0:
+				running_value = operate(running_value, look_ahead.value, current_token.type)
-					running_value = operate(previous_token.value, look_ahead.value, current_token.type)
+			#Set the previous_token to an invalid state so its not used by mistake.
-				else:
+			previous_token.type = token.TokenType.unknown
-					running_value = operate(running_value, look_ahead.value, current_token.type)
-				previous_token.type = token.TokenType.unknown
 			
 		elif current_token.type == token.TokenType.multiply or current_token.type == token.TokenType.divide:
 			tokens.append(current_token)
@@ -211,8 +220,12 @@ def handle_add_and_subtract(tokens):
 				tokens.append(token.CToken(running_value, token.TokenType.constant))
 			
 			running_value = handle_multiply_and_division(tokens)
-			
+			#Set the previous_token to an invalid state so its not used by mistake.
 			previous_token.type = token.TokenType.unknown
+		
+		#elif current_token.type == token.TokenType.power:
+			#In theory, if we hit this branch the expression wuld look something like this: a ^ b.
+			
 			
 	return running_value
 				

token.py

@@ -52,13 +52,13 @@ class TokenType:
 
 	@staticmethod
 	def get_operator(character):
-		"""
+		#
-        Accepts an individual character and returns either the math operator TokenType or unknown.
+        #Accepts an individual character and returns either the math operator TokenType or unknown.
-        """
+        #
 		if not character in TokenType.OPERATORS:
 			return TokenType.unknown
 		return TokenType.OPERATORS[character]
 	
 	@staticmethod
-	def get_operator_name(tokenType):
+	def get_token_type_name(tokenType):
 		return TokenType.TOKEN_NAMES[tokenType]