def is_valid_body(term):
"""Whether a term is a valid body of a definition.
Valid terms:
* must be closed (no free IVARs)
* must be normal
* must have ABS only at the top level
* cannot be TOP or BOT.
"""
assert isinstance(term, Term)
if not is_closed(term):
log_error('Not closed: {}'.format(term))
return False
if not bohm.is_normal(term):
log_error('Not normal: {}'.format(term))
return False
# TODO Decide whether TOP and BOT should be allowed as bodies.
# if term is TOP or term is BOT:
# log_error('Disallowed: {}'.format(term))
# return False
if is_join(term):
return all(is_valid_body(part) for part in bohm.iter_join(term))
while is_abs(term):
term = term[1]
if not is_abs_free(term):
log_error('ABS in inner term: {}'.format(term))
return False
return True
def test_try_compute_step_runs(term):
for step in xrange(5):
with xfail_if_not_implemented():
result = bohm.try_compute_step(term)
if is_normal(term):
assert result is None
return
else:
assert isinstance(result, Term)
def test_try_compute_step_runs(code):
for step in xrange(5):
with xfail_if_not_implemented():
result = try_compute_step(code)
if is_normal(code):
assert result is None
return
else:
assert is_code(result)
def test_linear_is_normal(term):
hypothesis.assume(is_linear(term))
assert is_normal(term)
def test_is_normal(term, expected_try_compute_step):
expected = (expected_try_compute_step is None)
assert is_normal(term) is expected
def test_linear_is_normal(code):
hypothesis.assume(is_linear(code))
assert is_normal(code)