def test_evaluate_3var_expr(self):
expr = 'a & b | c'
variableMap = {'a' : 0, 'b' : 1 , 'c' : 0 }
postfix = infixToPostfix(expr)
root = postfixToExpressionTree(postfix)
root.in_traversal()
print('')
self.assertEqual(evaluateExpr(postfix, variableMap), 0)
def test_evaluate_expr_true(self):
expr = 'a | !a'
variableMap = {'a' : 0}
postfix = infixToPostfix(expr)
root = postfixToExpressionTree(postfix)
root.in_traversal()
print('')
self.assertEqual(evaluateExpr(postfix, variableMap), 1)
def test_evaluate_complex_expr(self):
expr = '(a & (!b | b)) | (!a & (!b | b))'
variableMap = {'a' : 0, 'b' : 1}
postfix = infixToPostfix(expr)
root = postfixToExpressionTree(postfix)
root.in_traversal()
print('')
self.assertEqual(evaluateExpr(postfix, variableMap), 1)
def isTautology(self):
'''
Determines whether a statement given is a tuatology or not
Returns:
This function returns whether a given statement is tautology or not
'''
logging.debug (self.statement)
(variableMap, uniqueVaraibles) = self._getVariableMap(self.statement)
#optimization step is that if all are unique variables, it won't be tautology
logging.debug (variableMap, uniqueVaraibles)
if uniqueVaraibles:
return False
numVariables = len(variableMap)
postfix = infixToPostfix(self.statement)
root = postfixToExpressionTree(postfix)
for i in range(pow(2, numVariables)):
for e in enumerate(variableMap):
offset = e[0]
key = e[1]
variableMap[key] = (i & (1 << offset)) >> offset
if not self._evaluateExprTree(root, variableMap):
return False
return True
def isTautology(self):
'''
Determines whether a statement given is a tuatology or not
Returns:
This function returns whether a given statement is tautology or not
'''
logging.debug(self.statement)
(variableMap, uniqueVaraibles) = self._getVariableMap(self.statement)
#optimization step is that if all are unique variables, it won't be tautology
logging.debug(variableMap, uniqueVaraibles)
if uniqueVaraibles:
return False
numVariables = len(variableMap)
postfix = infixToPostfix(self.statement)
root = postfixToExpressionTree(postfix)
for i in range(pow(2, numVariables)):
for e in enumerate(variableMap):
offset = e[0]
key = e[1]
variableMap[key] = (i & (1 << offset)) >> offset
if not self._evaluateExprTree(root, variableMap):
return False
return True
def test_simple_expr(self):
expr = 'a'
self.assertEqual(infixToPostfix(expr), 'a')
def test_evaluate_expr_simple(self):
expr = 'a'
variableMap = {'a' : 0}
postfix = infixToPostfix(expr)
self.assertEqual(evaluateExpr(postfix, variableMap), 0)
def test_expr_with_not_complex(self):
expr = '(a & (!b | b)) | (!a & (!b | b))'
self.assertEqual(infixToPostfix(expr), 'ab!b|&a!b!b|&|')
def test_expr_with_not_same(self):
expr = 'a & !a'
self.assertEqual(infixToPostfix(expr), 'aa!&')
def test_expr_with_not(self):
expr = '!a & !b'
self.assertEqual(infixToPostfix(expr), 'a!b!&')
def test_tree_evaluate_3var_expr(self):
expr = 'a & b | c'
variableMap = {'a' : 0, 'b' : 1 , 'c' : 0 }
postfix = infixToPostfix(expr)
root = postfixToExpressionTree(postfix)
self.assertEqual(evaluateExprTree(root, variableMap), 0)
def test_tree_evaluate_complex_expr(self):
expr = '(a & (!b | b)) | (!a & (!b | b))'
variableMap = {'a' : 0, 'b' : 1}
postfix = infixToPostfix(expr)
root = postfixToExpressionTree(postfix)
self.assertEqual(evaluateExprTree(root, variableMap), 1)
def test_complex_expr_braces(self):
expr = 'a & (b | c)'
self.assertEqual(infixToPostfix(expr), 'abc|&')
def test_tree_evaluate_expr_true(self):
expr = 'a | !a'
variableMap = {'a' : 0}
postfix = infixToPostfix(expr)
root = postfixToExpressionTree(postfix)
self.assertEqual(evaluateExprTree(root, variableMap), 1)
def test_simple_expr_braces(self):
expr = 'a&b'
self.assertEqual(infixToPostfix(expr), 'ab&')