def testLeftArcIsNotValidWithRoot(self):
"""invalid left when second item on the stack is root"""
state = tdatatypes.State(5)
system = ArcStandard()
system.applyTransition(state, ArcStandard.SHIFT)
self.assertFalse(system.isValidTransition(state, ArcStandard.LEFTARC))
def testRightArcHead(self):
"""RightArcStandard introduces an arc from the top-most token on the stack to the second one"""
state = tdatatypes.State(5)
system = ArcStandard()
system.applyTransition(state, ArcStandard.SHIFT)
system.applyTransition(state, ArcStandard.RIGHTARC)
self.assertEqual(state.arcs.getHead(0), -1)
def testLeftArcHead(self):
"""LeftArc introduces an arc from the second to the first item on the stack"""
state = tdatatypes.State(5)
system = ArcStandard()
system.applyTransition(state, ArcStandard.SHIFT)
system.applyTransition(state, ArcStandard.SHIFT)
system.applyTransition(state, ArcStandard.LEFTARC)
self.assertEqual(state.arcs.getHead(0), 1)
def testShift(self):
"""Shift takes the first token from the front of the buffer and pushes it onto the stack"""
state = tdatatypes.State(5)
system = ArcStandard()
system.applyTransition(state, ArcStandard.SHIFT)
self.assertEqual(state.buffer.toList(), [1, 2, 3, 4])
self.assertEqual(state.stack.toList(), [-1, 0])
def testLeftArcRemove(self):
"""LeftArc removes the second token on the stack"""
state = tdatatypes.State(5)
system = ArcStandard()
system.applyTransition(state, ArcStandard.SHIFT)
self.assertEqual(state.stack.toList(), [-1, 0])
system.applyTransition(state, ArcStandard.LEFTARC)
self.assertEqual(state.stack.toList(), [0])
def testRightArcRemove(self):
"""RightArcStandard removes the top-most token from the stack"""
state = tdatatypes.State(5)
system = ArcStandard()
system.applyTransition(state, ArcStandard.SHIFT)
self.assertEqual(state.stack.toList(), [-1, 0])
self.assertEqual(state.buffer.toList(), [1, 2, 3, 4])
system.applyTransition(state, ArcStandard.RIGHTARC)
self.assertEqual(state.stack.toList(), [-1])
self.assertEqual(state.buffer.toList(), [1, 2, 3, 4])
def applyTransition(self, state, tId):
self.transitions.append(tId)
return ArcStandard.applyTransition(self, state, tId)