def test_atom():
"""Ensure atom indicates atomicity."""
env = prelude.env()
assert env[wtypes.Symbol('atom?')].call([wtypes.Integer(1)],
env) == wtypes.Bool(True)
assert env[wtypes.Symbol('atom?')].call([quoted_list([wtypes.Integer(1)])],
env) == wtypes.Bool(False)
def test_equal():
"""Ensure equal tests equality properly."""
assert prelude.env()[wtypes.Symbol('eq?')].call(
[wtypes.Integer(4), wtypes.Integer(4)], {}) == wtypes.Bool(True)
assert prelude.env()[wtypes.Symbol('eq?')].call(
[wtypes.Integer(4), wtypes.Integer(2)], {}) == wtypes.Bool(False)
assert prelude.env()[wtypes.Symbol('eq?')].call(
[wtypes.Integer(4), wtypes.String('abc')], {}) == wtypes.Bool(False)
def test_parse_list():
"""Ensure we can parse lists."""
assert parser.parse_expr.parse('(1 abc "abc" #t #f +)') == wtypes.List([
wtypes.Integer(1),
wtypes.Symbol('abc'),
wtypes.String('abc'),
wtypes.Bool(True),
wtypes.Bool(False),
wtypes.Symbol('+'),
])
def cond(args: typing.List[wtypes.Expression],
env: wisp.env.Environment) -> wtypes.Expression:
"""Return the expression associated with the first test to return true."""
for arg in args:
if not isinstance(arg, wtypes.List):
raise exceptions.WispException('invalid cond form: %s' % args)
elif len(arg.items) != 2:
raise exceptions.WispException('invalid cond form: %s' % args)
body, test = arg.items
if (test == wtypes.Symbol('else') or
test.eval(env) == wtypes.Bool(True)):
return body.eval(env)
else:
return wtypes.Symbol('unspecified return value')
def test_eval_bool():
"""Ensure bools evaluate to themselves."""
assert wtypes.Bool(True).eval({}) == wtypes.Bool(True)
def test_parse_bool():
"""Ensure we can parse true and false."""
assert parser.parse_expr.parse('#t') == wtypes.Bool(True)
assert parser.parse_expr.parse('#f') == wtypes.Bool(False)
def is_atom(args: typing.List[wtypes.Expression],
env: wisp.env.Environment) -> wtypes.Bool:
"""Indicate whether we're passed a list or an atom."""
return wtypes.Bool(not isinstance(args[0], wtypes.List))
def is_equal(args: typing.List[wtypes.Expression],
env: wisp.env.Environment) -> wtypes.Bool:
"""Return a boolean indicating if the two elements are equal."""
return wtypes.Bool(args[0] == args[1])
def parse_false():
"""Parse a boolean false from a #f lexeme."""
yield parsec.string('#f')
return wtypes.Bool(False)
def parse_true():
"""Parse a boolean true from a #t lexeme."""
yield parsec.string('#t')
return wtypes.Bool(True)