Changed the JSON generator to generate JSON that includes the correct answer for the expression.

expression.py

@@ -0,0 +1,27 @@
+class Expression:
+	expression = ""
+	variables = []
+	
+	def __init__(self, expression_string, variables):
+		self.expression = expression_string
+		self.variables = variables
+		
+class Variable:
+	VARIABLE_TYPES = {
+		"i" : "Interest",
+		"I" : "Interest",
+		"n" : "Time",
+		"N" : "Time"
+	}
+	
+	def __init__(self, name, type, starting_point = 0, ending_point = 0):
+		self.name = name
+		self.type = type
+		self.starting_point = starting_point
+		self.ending_point = ending_point
+		
+	@staticmethod
+	def get_variable_type(variable_name):
+		if not variable_name in Variable.VARIABLE_TYPES:
+			return "Unknown"
+		return Variable.VARIABLE_TYPES[variable_name]