def ast_test_all_raise(error, test, *invalid):
for each in invalid:
try:
with assert_raises(error):
bind(each, test)
except:
print(each)
raise
def ast_test_all(test, mf_result, mf_expected, *term_pairs):
for term, expected in term_pairs:
result = bind(term, mf_result)
expected = bind(expected, mf_expected)
try:
test(result, expected)
except:
print(term)
print(result)
print(expected)
print()
raise
def test_monad_laws():
"Test if the basic monadic functions conform to the three Monad Laws."
from hornet.expressions import unit, bind, lift
x = ast.Name(id='x', ctx=load)
y = ast.Name(id='y', ctx=load)
z = ast.Name(id='z', ctx=load)
mx = unit(x)
binop = lambda u, op, v: unit(ast.BinOp(left=u, op=op(), right=v))
and_y = lambda u: binop(u, ast.BitAnd, y)
or_z = lambda u: binop(u, ast.BitOr, z)
y_and = lambda v: binop(y, ast.BitAnd, v)
z_or = lambda v: binop(z, ast.BitOr, v)
mfuncs = [unit, lift(identity), and_y, or_z, y_and, z_or]
# left identity:
for mf in mfuncs:
ast_eq(bind(mx, mf), mf(x))
# right identity:
ast_eq(bind(mx, unit), mx)
# associativity:
for mf, mg in itertools.product(mfuncs, repeat=2):
ast_eq(
bind(bind(mx, mf), mg),
bind(mx, lambda v: bind(mf(v), mg))
)