Wrote some more comments about the code.

main.py

@@ -3,7 +3,7 @@ import tokenizer
 import expression
 import calc_engine
 import factors
-import jsonpickle
+#import jsonpickle
 import itertools
 import copy
 
@@ -14,6 +14,8 @@ variables = {}
 var_types = {}
 
 def print_vars(vars):
+	# Utility function to print out the variables list to standard out.
+	
 	i = 0
 	for key in vars.keys():
 		var = vars[key]
@@ -25,6 +27,8 @@ def print_vars(vars):
 	print()
 	
 def modify_variable(var, vars):
+	# Acts as an interactive prompt that allows the user to modify any one variable that has been found in the formula string.
+	
 	print("%s is now selected." %(var.name))
 	print("The following properties are avaliable: Variable Type, Starting Point and Ending Point.")
 	print('Commands are "type", "start" and "end", respectly.')