def test_apply_user_function():
# backup function_env
import evaluator
initial_fundefs = evaluator.function_env
evaluator.function_env = {}
# test
define_function('triple', ['n'], ['*', 'n', 3])
ast = ['triple', 7]
assert 21 == evaluate({}, ast)
# restore function_env
evaluator.function_env = initial_fundefs
def test_apply_user_function():
# backup function_definitions
import evaluator
initial_fundefs = evaluator.function_definitions
evaluator.function_definitions = {}
# test
parts = 'triple', ['n'], ['*', 'n', 3]
define_function(parts)
ast = ['triple', 7]
assert 21 == evaluate({}, ast)
# restore function_definitions
evaluator.function_definitions = initial_fundefs
def test_evaluate_user_function_missing_argument(mod_body):
# backup function_definitions
import evaluator
initial_fundefs = evaluator.function_definitions
evaluator.function_definitions = {}
# test
define_function(('mod', ['m', 'n'], mod_body))
ast = ['mod', 19]
with raises(errors.MissingArgument) as excinfo:
evaluate({}, ast)
assert "Missing argument: 'mod' needs 2." == str(excinfo.value)
# restore function_definitions
evaluator.function_definitions = initial_fundefs
def repl(input_fn=input):
"""Read-Eval-Print-Loop"""
print(f'To exit, type {QUIT_COMMAND}', file=sys.stderr)
while True:
# ___________________________________________ Read
try:
line = input_fn('> ')
except EOFError:
break
if line == QUIT_COMMAND:
break
if not line:
continue
# ___________________________________________ Eval
current_exp = parse_exp(tokenize(line))
if isinstance(current_exp, list) and current_exp[0] == 'define':
result = define_function(current_exp[1:])
else:
try:
result = evaluate({}, current_exp)
except (errors.UndefinedVariable, errors.UndefinedFunction) as exc:
print('***', exc)
continue
# ___________________________________________ Print
print(result)
def repl(input_fn=input):
"""Read-Eval-Print-Loop"""
print(f'To exit, type {QUIT_COMMAND}', file=sys.stderr)
while True:
# ___________________________________________ Read
try:
source = multiline_input('> ',
'... ',
quit_cmd=QUIT_COMMAND,
input_fn=input_fn)
except (EOFError, QuitRequest):
break
except errors.UnexpectedCloseParen as exc:
print('***', exc)
continue
if not source:
continue
# ___________________________________________ Eval
current_exp = parse_exp(tokenize(source))
if isinstance(current_exp, list) and current_exp[0] == 'define':
result = define_function(current_exp[1:])
else:
try:
result = evaluate({}, current_exp)
except errors.EvaluatorException as exc:
print('***', exc)
continue
# ___________________________________________ Print
print(result)
def run(source_file, env=None):
"""Read and execute opened source file"""
source = source_file.read()
if env is None:
env = {}
tokens = tokenize(source)
while tokens:
try:
current_exp = parse_exp(tokens)
except errors.UnexpectedCloseParen as exc:
print('***', exc, file=sys.stderr)
break
if isinstance(current_exp, list) and current_exp[0] == 'define':
define_function(current_exp[1:])
else:
try:
evaluate(env, current_exp)
except errors.EvaluatorException as exc:
print('***', exc, file=sys.stderr)
continue
def test_define_function():
# backup function_definitions
import evaluator
initial_fundefs = evaluator.function_definitions
evaluator.function_definitions = {}
# test
parts = ['double', ['n'], ['*', 'n', 2]]
want_name = 'double'
want_formals = ['n']
want_body = ['*', 'n', 2]
got = define_function(parts)
assert '<UserFunction (double n)>' == got
new_func = evaluator.function_definitions[want_name]
assert want_name == new_func.name
assert want_formals == new_func.formals
assert want_body == new_func.body
# restore function_definitions
evaluator.function_definitions = initial_fundefs