def apply(self, state, id, data, prevs):
cur_item = state.get_proof_item(id)
assert cur_item.rule == "sorry", "revert intro: id is not a gap"
assert len(prevs) == 1, "revert intro: prevs must have length one"
pt = state.get_proof_item(prevs[0])
assert pt.rule == 'assume', "revert_intro: prev is not assume"
state.set_line(id,
'sorry',
th=Thm.implies_intr(pt.th.prop, cur_item.th))
item = state.get_proof_item(id.incr_id(1))
state.set_line(id.incr_id(1),
item.rule,
args=item.args,
prevs=[p for p in item.prevs if p != prevs[0]],
th=item.th)
state.remove_line(prevs[0])
def testImpliesIntr3(self):
th = Thm([], B)
self.assertEqual(Thm.implies_intr(A, th), Thm([],
Term.mk_implies(A, B)))
def testImpliesIntr2(self):
th = Thm([A, B], B)
self.assertEqual(Thm.implies_intr(A, th), Thm([B], Implies(A,B)))