def test_or_shortcircuit():
source = ['(or #t never-reached)']
exp = parse_tokens(tokenize(source))[0]
try:
eval_in_env(exp, Environment([]))
except Exception as e:
assert str(e) != 'unknown variable "never-reached"'
def test_eval_recursion():
env = Environment([['sumto', ['closure', ['lambda', ['n'],
['if', ['<', 'n', 1],
0,
['+', 'n', ['sumto', ['-', 'n', 1]]]]],
[]]]])
exp = ['sumto', 3]
assert eval_in_env(exp, env) == 6
def repl():
color_print('****************************************', 'blue')
color_print('lis.py - a simple Lisp written in Python', 'blue')
color_print('(c) Nick Collins, 2013', 'blue')
color_print('****************************************', 'blue')
env = Environment([])
while True:
try:
user_input = raw_input('lis.py> ')
exp = parse_tokens(tokenize([user_input]))[0]
tmp_env = Environment([], env)
color_print(eval_in_env(exp, tmp_env), 'green')
env = tmp_env
except EOFError:
color_print('\nLeaving lis.py.', 'blue')
break
except LisNameError as e:
color_print(e, 'red')
except LisSyntaxError as e:
color_print(e, 'red')
except Exception as e:
color_print(e, 'red')
print('*** Invalid input ***')
def test_eval_if():
exp = ['if', True, 3, 4]
assert eval_in_env(exp, Environment([])) == 3
def test_eval_cond_false():
exp = ['cond', [['>', 4, 4], 1], ['else', 0]]
assert eval_in_env(exp, Environment([])) == 0
def test_eval_set():
env = Environment([['a', 0]])
exp = ['set!', 'a', 10]
eval_in_env(exp, env)
assert env.lookup('a') == 10
def test_nullcheck_2():
source = ['(null? (cons 1 null))']
exp = parse_tokens(tokenize(source))[0]
assert eval_in_env(exp, []) == False
def test_list():
source = ['(list 1 2 (+ 1 2) 4)']
exp = parse_tokens(tokenize(source))[0]
assert eval_in_env(exp, []) == [1, 2, 3, 4]
def test_eval_recursion_2():
env = Environment([['factorial', ['closure', ['lambda', ['n'],
['if', ['<', 'n', 1], 1, ['*', 'n', ['factorial', ['-', 'n', 1]]]]], []]]])
exp = ['factorial', 5]
assert eval_in_env(exp, env) == 120
def test_gt():
source0, source1 = ['(> 2 2)'], ['(> 3 2)']
exp0 = parse_tokens(tokenize(source0))[0]
exp1 = parse_tokens(tokenize(source1))[0]
assert eval_in_env(exp0, Environment([])) == False
assert eval_in_env(exp1, Environment([])) == True
def test_eval_closure():
env = Environment([['add3', ['closure', ['lambda', ['x'], ['+', 'x', 3]], []]]])
exp = ['add3', 10]
assert eval_in_env(exp, env) == 13
def test_subtract():
source = ['(- 10 14)']
exp = parse_tokens(tokenize(source))[0]
assert eval_in_env(exp, Environment([])) == -4
def test_divide():
source = ['(/ 10 3)']
exp = parse_tokens(tokenize(source))[0]
assert eval_in_env(exp, Environment([])) == 3
def test_multiply():
source = ['(* 1 3 5)']
exp = parse_tokens(tokenize(source))[0]
assert eval_in_env(exp, Environment([])) == 15
def test_cons():
source = ['(cons (+ 1 3 5) null)']
exp = parse_tokens(tokenize(source))[0]
assert eval_in_env(exp, Environment([])) == [9]
def test_nullcheck_3():
source = ['(null? (cdr (list 1)))']
exp = parse_tokens(tokenize(source))[0]
assert eval_in_env(exp, []) == True
def test_eval_let():
exp = ['let', [['x', 3], ['y', 10]], ['+', 'x', 'y']]
assert eval_in_env(exp, Environment([])) == 13
def test_add():
source = ['(+ 1 3 5)']
exp = parse_tokens(tokenize(source))[0]
assert eval_in_env(exp, Environment([])) == 9
def test_eval_define():
env = Environment([])
exp = ['define', 'a', 3]
eval_in_env(exp, env)
#assert env._env == [['a', 3]]
assert env.lookup('a') == 3
def test_and_false():
source = ['(and (> 2 1) (= 1 2) #t)']
exp = parse_tokens(tokenize(source))[0]
assert eval_in_env(exp, Environment([])) == False
def test_eval_closure_2():
env = Environment([['ifthen', ['closure', ['lambda', ['x'], ['if', True, 'x', 3]], []]]])
exp = ['ifthen', 10]
assert eval_in_env(exp, env) == 10
def test_or_false():
source = ['(or (> 2 10) (= 1 2) #f)']
exp = parse_tokens(tokenize(source))[0]
assert eval_in_env(exp, Environment([])) == False
def test_eval_add_const():
exp = ['+', 3, 4]
res = eval_in_env(exp, Environment([]))
assert res == 7
def test_eval_modulo():
assert 0 == eval_in_env(['modulo', 9, 3], Environment([]))
assert 1 == eval_in_env(['modulo', 10, 3], Environment([]))
assert 2 == eval_in_env(['modulo', 11, 3], Environment([]))
def test_eval_anon():
exp = [['lambda', ['x'], ['+', 'x', 'x']], 7]
assert eval_in_env(exp, Environment([])) == 14
def test_cdr():
source = ['(cdr (cons 1 null))']
exp = parse_tokens(tokenize(source))[0]
assert eval_in_env(exp, []) == []
def test_eval_begin():
exp = ['begin', ['define', 'a', 0], ['set!', 'a', 10], 'a']
assert eval_in_env(exp, Environment([])) == 10
def test_nullcheck():
source = ['(null? null)']
exp = parse_tokens(tokenize(source))[0]
assert eval_in_env(exp, []) == True
def test_eval_not():
assert True == eval_in_env(['not', False], Environment([]))
assert False == eval_in_env(['not', True], Environment([]))
assert False == eval_in_env(['not', 'null'], Environment([]))
def test_car():
source = ['(car (cons 1 null))']
exp = parse_tokens(tokenize(source))[0]
assert eval_in_env(exp, Environment([])) == 1