49 lines
1.6 KiB
Python
49 lines
1.6 KiB
Python
class Expression:
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# This object represents all the needed initial data about an expression that is to be parsed.
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expression = "" # The formula to parse as a string.
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# correct_response = 0
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wrong_response = 0 # The incorrect response that was entered by the student.
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variables = [] # A list of Variable.
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def __init__(self, expression_string, variables, wrong_response):
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self.expression = expression_string
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self.variables = variables
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self.wrong_response = wrong_response
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class Variable:
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# This object represents a variable that is found in the formula. It encodes the name, the type of variable
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# and the starting point from which to look for mutations in the variable's value.
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name = ""
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type = ""
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starting_point = 0
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# ending_point = 0
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VARIABLE_TYPES = {
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"i" : "Interest",
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"I" : "Interest",
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"n" : "Time",
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"N" : "Time",
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"k" : "Installment",
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"K" : "Installment"
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}
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def __init__(self, name, type, starting_point = 0, ending_point = 0):
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self.name = name
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self.type = type
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self.starting_point = starting_point
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self.ending_point = ending_point
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@staticmethod
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def get_variable_type(variable_name):
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# Utilitie function to get the variable's type from it's name.
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# For example, a variable with 'i' in its name is an Interest type.
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# Returns the variable's type as a string or 'Unknown' otherwise.
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if not variable_name[0] in Variable.VARIABLE_TYPES:
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return "Unknown"
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return Variable.VARIABLE_TYPES[variable_name[0]]
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def __str__(self):
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return "Name: %s Type: %s Start: %f" %(self.name, Variable.get_variable_type(self.name), self.starting_point)
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