Updated the tokenizer to use a deque object instead of a list. The old calc_engine should still work, not tested. New parser code works with this change.

tokenizer.py

@@ -1,10 +1,11 @@
 import ptoken as token
+from collections import deque
 
 def get_tokens_from_expression_string(expression_string):
 	# Takes user input (in the format of a string) of an actuarial formula and parses the formula to its components.
 	# Returns the list of Token objects that represent the string expression.
 	
-	tokens = []  # List of objects of Token class
+	tokens = deque()
 	tmp = ""
 	parsing_number = False
 	symbols_dic = {}  # Dictionary to keep track of the no. of times each variable appears.
@@ -114,22 +115,6 @@ def peek_list(tokens):
         return tokens[-1]
     else:
         raise IndexError("The token list is empty.", tokens)
-
-def replace_variables(tokens, new_constants):
-	# Searches and replaces variable Tokens with Constant TokenType Token objects. Doing so enables the calc_engine to never have
-	# to even know variable token types exist.
-	# Returns a list of Token objects with the variables replaced by the supplied list of new constants.
-	newTokenList = []
-	for t in tokens:
-		if t.type == token.TokenType.variable:
-			if not t.is_negative_variable:
-				newTokenList.append(token.Token(new_constants.pop(0), token.TokenType.constant))
-			else:
-				newTokenList.append(token.Token(new_constants.pop(0) * -1, token.TokenType.constant))
-		else:
-			newTokenList.append(token.Token(t.value, t.type))
-			
-	return newTokenList
 	
 def print_token_list(tokens):
 	# Prints the list of Tokens to standard out.