def encode_num(num):
if not isinstance(num, int) or isinstance(num, bool) or not num >= 0:
raise TypeError(num)
result = lib.zero
for i in xrange(num):
result = lib.succ(result)
return result
'encode_error': [None, 0, 1, 2, [None], [True]],
'decode_error': [I, B, C, APP(C, B)],
},
'byte': {
'ok': [
(lib.byte_table[ord(b'a')], b'a'),
(lib.byte_table[0x00], b'\x00'),
(lib.byte_table[0xff], b'\xff'),
],
'encode_error': [0, ['a'], 'asdf'],
'decode_error': [I, K, B, C, APP(C, B)],
},
'num': {
'ok': [
(lib.zero, 0),
(lib.succ(lib.zero), 1),
(lib.succ(lib.succ(lib.zero)), 2),
(lib.succ(lib.succ(lib.succ(lib.zero))), 3),
],
'encode_error': [None, False, True, [0], [True]],
},
('prod', 'bool', 'num'): {
'ok': [
(lib.pair(lib.true, lib.zero), (True, 0)),
(lib.pair(lib.false, lib.succ(lib.succ(lib.zero))), (False, 2)),
],
'encode_error': [None, (), (True,), [True, 0], True, 0, 'asdf']
},
('sum', 'bool', 'num'): {
'ok': [
(lib.inl(lib.true), (True, True)),
# ----------------------------------------------------------------------------
# Numerals as Y Maybe
def encode_num(num):
if not isinstance(num, int) or isinstance(num, bool) or not num >= 0:
raise TypeError(num)
result = lib.zero
for i in xrange(num):
result = lib.succ(result)
return result
_pred_var = unification.var('pred')
_succ_pattern = lib.succ(_pred_var)
def decode_num(code):
result = 0
while True:
if code is lib.zero:
return result
match = unification.unify(_succ_pattern, code)
if not match:
raise TypeError(code)
result += 1
code = match[_pred_var]
# ----------------------------------------------------------------------------
