def fn(pair):
# we use an empty pair to 'capture' the nodes
# produced by the grouped exprs.
p2 = prepare(pair.tail)
p2 = expr(p2)
node = Node(fn, p2.nodes)
return Pair(pair.nodes + [node], p2.tail)
def test_prepare():
given = ["k"]
after = Pair(Vec(), Vec(*given))
assert prepare(given) == after
def test_term_no_match():
given = prepare([B])
with pytest.raises(ValueError):
K(given)
def test_term_empty_seq():
given = prepare([])
with pytest.raises(ValueError):
K(given)
def test_term():
given = prepare([N])
after = Pair([N], [])
assert K(given) == after
def test_term_multiple():
given = prepare([N,B])
after = Pair([N], [B])
assert K(given) == after
def test_maybe():
m = maybe(Ta)
assert m(prepare([Nb])) == Pair([], [Nb])
assert m(prepare([Na])) == Pair([Na], [])
def test_null():
given = prepare([N])
after = given
assert null(given) == after
def test_option_empty():
with pytest.raises(ValueError):
assert option(Ta, Tb)(prepare([Nc]))
def test_option():
opt = option(Ta, Tb, Tc)
for node in [Na, Nb]:
assert opt(prepare([node])) == Pair([node], [])
def test_repeat():
r = repeat(Ta)
given = prepare([Na]*10)
after = Pair([Na]*10, [])
assert r(given) == after
def test_group():
g = group(Ta)
given = prepare([Na])
after = Pair([Node(g, [Na])], [])
assert g(given) == after
def test_sequence():
s = sequence(Ta, Tb)
given = prepare([Na, Nb])
after = Pair([Na, Nb], [])
assert s(given) == after
