def curried(s):
part = Just(s)
part >>= expandCharacters(ce)
part >>= replaceCharacters(cr)
part >>= replaceCharacters(ci)
return part.value
def eval(exp: Expr) -> Maybe:
if isinstance(exp, Val):
return Just(exp.n)
elif isinstance(exp, Div):
return eval(exp.a) >> (lambda x:\
eval(exp.b) >> (lambda y:\
safediv(x, y)))
def eval_do(exp: Expr) -> Maybe:
if isinstance(exp, Val):
return Just(exp.n)
elif isinstance(exp, Div):
n = eval_do(exp.a)
m = eval_do(exp.b)
return safediv(n.getValue(), m.getValue()) if n and m else None
def _get_multi(rej, res):
try:
r = memcache.get_multi(keys, key_prefix=prefix)
res([
Nothing if r.get(k) is None else Just(r.get(k)) for k in keys
])
except Exception as e:
rej(err.wrap(e))
def current():
# () -> Maybe User
try:
u = users.get_current_user()
if u is None:
return Nothing
else:
return Just(u)
except Exception as e:
return Nothing
def _get(rej, res):
try:
ent = self._model.get_by_id(uid)
if ent is None:
res(Nothing)
else:
res(Just(ent))
except Exception as e:
rej(err.wrap(e))
def curried(s):
parts = []
for token in expandToken(self.tokenExpand, tokenize(s)):
part = Just(token.lower())
part >>= replaceToken(self.tokenReplace)
part >>= ignoreToken(self.tokenIgnore)
part >>= expandCharacters(ce)
part >>= replaceCharacters(cr)
part >>= replaceCharacters(ci)
parts.append(part)
joined = ''.join([x.value for x in parts if x.value])
return joined
def curried(s):
parts = []
for token in expandToken(self.tokenExpand, tokenize(s)):
part = Just(token.lower())
part >>= replaceToken(self.tokenReplace)
part >>= ignoreToken(self.tokenIgnore)
part >>= expandCharacters(ce)
part >>= replaceCharacters(cr)
part >>= replaceCharacters(ci)
part >>= expandCharacters(r)
parts.append(part)
delimited = []
for pair in window([x.value for x in parts if x.value]):
delimited.append(pair[0])
if pair[1][0] not in ['.', '%']:
delimited.append('+')
delimited.append(parts[-1].value)
return ''.join(delimited)
def test_mplus_with_just_and_nothing(self):
self.givenMonoids(First(Just(1)), Nothing)
self.ensure_mconcat_equals(First(Just(1)))
def test_right_identity(self):
self.givenMonoid(First(Just(9)))
self.ensure_monoid_plus_zero_equals(First(Just(9)))
def replaceCharacters(table, s):
b = unicodedata.normalize('NFKD', s)
s = b.translate(table)
return Just(s)
def testEqualityOfIdenticalTypes(self):
self.givenMonads(Just(8), Just(8))
self.ensureMonadsAreEqual()
def monad_function_f(self, x):
return Just(x + 10)
def test_mplus_with_two_just_values(self):
self.givenMonoids(Last(Just(1)), Last(Just(2)))
self.ensure_mconcat_equals(Last(Just(2)))
def testSafeRootTo9() -> bool:
return all(testSafeRoot(n) == Just(2) for n in range(10))
from pymonad.Maybe import Just, Nothing
from pymonad.List import List
def add(x, y):
return x + y
add << Just(7) & Just(8) # returns Just(15)
add << Nothing & Just(8) # returns Nothing
add << Just(7) & Nothing # returns Nothing
add << List(1, 2, 3) & List(4, 5, 6) # returns List(5, 6, 7, 6, 7, 8, 7, 8, 9)
def testMonadComparisonException(self):
self.givenMonads(StringWriter(8, "log message"), Just(8))
self.ensureComparisonRaisesException()
def test_left_identity(self):
self.givenMonoid(Last(Just(9)))
self.ensure_zero_plus_monoid_equals(Last(Just(9)))
def safeSqrt(val: float) -> Maybe:
return Nothing if val < 0 else Just(sqrt(val))
def test_associativity(self):
self.givenMonoids(Last(Just(1)), Last(Just(2)), Last(Just(3)))
self.ensure_associativity()
def _get(rej, res):
try:
r = memcache.get(key)
res(Nothing if r is None else Just(r))
except Exception as e:
rej(err.wrap(e))
def test_mplus_with_nothing_and_just(self):
self.givenMonoids(Nothing, Last(Just(1)))
self.ensure_mconcat_equals(Last(Just(1)))
def replaceToken(table, s):
return Just(table[s]) if s in table else Just(s)
def monad_function_g(self, x):
return Just(x * 5)
def testInequalityOfJustAndNothing(self):
self.givenMonads(Just(8), Nothing)
self.ensureMonadsAreNotEqual()
def safediv(a: int, b: int) -> Maybe:
if b == 0:
return Nothing
else:
return Just((a // b))
def testMonadComparisonExceptionWithJust(self):
self.givenMonads(Just(8), Reader(8))
self.ensureComparisonRaisesException()
def ignoreToken(table, s):
return Nothing if s in table else Just(s)
def expandCharacters(table, s):
expanded = [table[c] if c in table else c for c in s]
return Just(''.join(expanded))