def test_dotted_list():
"""Check that dotted lists get tokenized correctly"""
entry = tokenize("(a b c . (d . e))")[0]
assert entry == HyCons(
HySymbol("a"),
HyCons(HySymbol("b"),
HyCons(HySymbol("c"), HyCons(HySymbol("d"), HySymbol("e")))))
def test_cons_replacing():
"""Check that assigning to a cons works as expected"""
cons = HyCons("foo", "bar")
cons[0] = "car"
assert cons == HyCons("car", "bar")
cons[1:] = "cdr"
assert cons == HyCons("car", "cdr")
try:
cons[:] = "foo"
assert True is False
except IndexError:
pass
def paren(p):
cont = p[1]
# Dotted lists are expressions of the form
# (a b c . d)
# that evaluate to nested cons cells of the form
# (a . (b . (c . d)))
if len(cont) >= 3 and isinstance(cont[-2], HySymbol) and cont[-2] == ".":
reject_spurious_dots(cont[:-2], cont[-1:])
if len(cont) == 3:
# Two-item dotted list: return the cons cell directly
return HyCons(cont[0], cont[2])
else:
# Return a nested cons cell
return HyCons(cont[0], paren([p[0], cont[1:], p[2]]))
# Warn preemptively on a malformed dotted list.
# Only check for dots after the first item to allow for a potential
# attribute accessor shorthand
reject_spurious_dots(cont[1:])
return HyExpression(p[1])
def test_cons_slicing():
"""Check that cons slicing works as expected"""
cons = HyCons("car", "cdr")
assert cons[0] == "car"
assert cons[1:] == "cdr"
try:
cons[:]
assert True is False
except IndexError:
pass
try:
cons[1]
assert True is False
except IndexError:
pass
def test_simple_cons():
"""Check that cons gets tokenized correctly"""
entry = tokenize("(a . b)")[0]
assert entry == HyCons(HySymbol("a"), HySymbol("b"))