Updated exceptions to be more fitting, fixed a parse bug in the tokenizer and added the start of the calc engine.

calc_engine.py

@@ -0,0 +1,25 @@
+import token
+
+def calculate_results(tokens):
+	
+	return 0
+
+def peek_list(tokens):
+    if tokens:
+        return tokens[-1]
+    else:
+        raise IndexError("The token list is empty.", tokens)
+
+def operate(n1, n2, tokenType):
+	if tokenType == token.TokenType.add:
+		print("Adding %d and %d to get %d." %(n1, n2, n1 + n2))
+	elif tokenType == token.TokenType.subtract:
+		print("Subtracting %d and %d to get %d." %(n1, n2, n1 - n2))
+	elif tokenType == token.TokenType.multiply:
+		print("Multiplying %d and %d to get %d" %(n1, n2, n1 * n2))
+	elif tokenType == token.TokenType.divide:
+		print("Dividing %d and %d to get %d" %(n1, n2, n1 / n2))
+	elif tokenType == token.TokenType.power:
+		print("Raising %d to the power of %d to get %d" %(n1, n2, n1**n2))
+	else:
+		raise TypeError("Invalid operator value " + str(tokenType) + ".", tokenType)

main.py

@@ -1,7 +1,7 @@
 import token
 import tokenizer
 #userInput = input('Enter your formula: ')
-tokens = tokenizer.get_tokens_from_expression_string("1 + 2 / 3 (3 * 4) 5")
+tokens = tokenizer.get_tokens_from_expression_string("i + 2 / i (3 * n) 5")
 
 for t in tokens:
 	print("%s (%s) " %(t.value, token.TokenType.get_operator_name(t.type)), end = "")

tokenizer.py

@@ -14,7 +14,7 @@ def get_tokens_from_expression_string(expression_string):
 		c = expression_string[i]
 		if c == '.' or c.isdigit():
 			if tmp.count('.') == 1:
-				raise ValueError("Invalid grammar, to many periods in number!")
+				raise SyntaxError("Invalid grammar, to many periods in number. Found at position " + str (i) + ".")
 			if len(tokens) > 1:
 				lookBehind = tokens[-1]
 				if lookBehind.type == token.TokenType.exp_end:
@@ -49,7 +49,7 @@ def get_tokens_from_expression_string(expression_string):
 		elif c != ' ':
 			if len(tokens) > 1:
 				lookBehind = tokens[-1]
-				if lookBehind.type == TokenType.exp_end:
+				if lookBehind.type == token.TokenType.exp_end:
 					tokens.append(token.CToken("^", token.TokenType.power))
 			if (i + 1) < len(expression_string):
 				lookAHead = expression_string[i + 1]
@@ -72,17 +72,3 @@ def get_tokens_from_expression_string(expression_string):
 
 	return tokens
 
-def operate(n1, n2, tokenType):
-	if tokenType == token.TokenType.add:
-		print("Adding %d and %d to get %d." %(n1, n2, n1 + n2))
-	elif tokenType == token.TokenType.subtract:
-		print("Subtracting %d and %d to get %d." %(n1, n2, n1 - n2))
-	elif tokenType == token.TokenType.multiply:
-		print("Multiplying %d and %d to get %d" %(n1, n2, n1 * n2))
-	elif tokenType == token.TokenType.divide:
-		print("Dividing %d and %d to get %d" %(n1, n2, n1 / n2))
-	elif tokenType == token.TokenType.power:
-		print("Raising %d to the power of %d to get %d" %(n1, n2, n1**n2))
-	else:
-		raise ValueError("Invalid operator value.")
-