def problem_A16(grades):
tests1 = [
(
"""(define (square x) (* x x))
(define (f x y)
(let ((a (+ 1 (* x y)))
(b (- 1 y)))
(+ (* x (square a))
(* y b)
(* a b))))
(f 3 4)""",
456,
),
]
tests2 = [
(
"""(define x 3)
(define y 4)
(let ((x (+ y 2))
(y (+ x 1)))
(cons x y))""",
Pair(6, 4),
),
("""(let ((x 'hello)) x)""", "hello"),
]
if check_func(scheme_eval, tests1, comp=scheme_equal):
return True
if check_func(scheme_eval, tests2, comp=scheme_equal):
return True
def problem_2(grades):
tests1 = [
('(a . b)', Pair('a', 'b')),
('(a)', Pair('a', nil)),
('(a b . c)', Pair('a', Pair('b', 'c')))
]
tests2 = [
('(a b . c d)', 'Error'),
('((a b) (c (d (e f))))',
pairify([['a', 'b'], ['c', ['d', ['e', 'f']]]])),
('(a . (b . (c . (d . ()))))',
pairify(['a', 'b', 'c', 'd'])),
('(. . 2)', 'Error'),
('(2 . 3 4 . 5)', 'Error'),
]
if check_func(catch_syntax_error(read_line), tests1, comp=scheme_equal):
return True
if check_func(catch_syntax_error(read_line), tests2, comp=scheme_equal):
return True
def problem_2(grades):
tests1 = [
("(a . b)", Pair("a", "b")),
("(a)", Pair("a", nil)),
("(a b . c)", Pair("a", Pair("b", "c"))),
]
tests2 = [
("(a b . c d)", "Error"),
("((a b) (c (d (e f))))",
pairify([["a", "b"], ["c", ["d", ["e", "f"]]]])),
("(a . (b . (c . (d . ()))))", pairify(["a", "b", "c", "d"])),
("(. . 2)", "Error"),
("(2 . 3 4 . 5)", "Error"),
("(2 (3 . 4) 5)", Pair(2, Pair(Pair(3, 4), Pair(5, nil)))),
]
if check_func(catch_syntax_error(read_line), tests1, comp=scheme_equal):
return True
if check_func(catch_syntax_error(read_line), tests2, comp=scheme_equal):
return True
def pairify(lst):
if not lst:
return nil
if type(lst) is not list:
return lst
return Pair(pairify(lst[0]), pairify(lst[1:]))
def pairify(lst): # parify从函数的名字就可以听出，是将lst Pair化
if not lst:
return nil # 这个nil是全局唯一一份的nil
if type(lst) is not list:
return lst
return Pair(pairify(lst[0]), pairify(lst[1:]))
