Validation¶
from pymonet.validation import Validation
def test_validation_is_fail():
assert Validation.fail(['fail']).is_fail()
def validate_length(value):
if len(value) < 5:
return Validation.fail(['value not long enough'])
return Validation.success()
def validate_uppercase(value):
if value[0].upper() != value[0]:
return Validation.fail(['value not uppercase'])
return Validation.success()
def validate_contains_special_character(value):
if re.match(r'^[a-zA-Z0-9_]*$', value):
return Validation.fail(['value not contains special character'])
return Validation.success()
def validate(value):
return (Validation.success(value)
.ap(validate_length)
.ap(validate_uppercase)
.ap(validate_contains_special_character))
validate('Success$') # Validation['Success$', []]
validate('Success') # Validation['Success$', ['value not uppercase']]
validate('S$') # Validation['Success$', ['value not long enough']]
validate('s$') # Validation['Success$', ['value not long enough', 'value not uppercase']]
validate('s') # Validation['Success$', ['value not long enough', 'value not uppercase', 'value not contains special character']]
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class
pymonet.validation.Validation(value, errors)¶ It that can hold either a success value or a failure value and has methods for accumulating errors
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__eq__(other)¶ Two Validations are equals when values and errors lists are equal.
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ap(fn)¶ It takes as a parameter function returning another Validation. Function is called with Validation value and returns new Validation with previous value and concated new and old errors.
- Parameters
monad (Function(A) -> Validation[Any, List[E]]) – monad contains function
- Returns
new validation with stored errors
- Return type
Validation[A, List[E]]
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bind(folder)¶ Take function and applied this function on current Validation value and returns folder result.
- Parameters
mapper (Function(A) -> Validation[B, E]) – mapper function
- Returns
new Validation with mapped value
- Return type
Validation[B, E]
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classmethod
fail(errors=[])¶ Returns failed Validation with None as value and errors list.
- Params errors
list of errors to store
- Returns
Failed Validation
- Return type
Validation[None, List[E]]
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is_fail()¶ Returns True when errors list are not empty.
- Returns
True for empty errors not list
- Return type
Boolean
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is_success()¶ Returns True when errors list are empty.
- Returns
True for empty errors list
- Return type
Boolean
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map(mapper)¶ Take function (A) -> B and applied this function on current Validation value.
- Parameters
mapper (Function(A) -> B) – mapper function
- Returns
new Validation with mapped value and previous errors
- Return type
Validation[B, List[E]]
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classmethod
success(value=None)¶ Returns successful Validation with value and empty errors list.
- Params value
value to store in Validation
- Returns
Successful Validation
- Return type
Validation[A, []]
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to_either()¶ Transform Validation to Either.
- Returns
Right monad with previous value when Validation has no errors, in other case Left with errors list
- Return type
Right[A] | Left[E]
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to_lazy()¶ Transform Validation to Try.
- Returns
Lazy monad with function returning Validation value
- Return type
Lazy[Function() -> (A | None)]
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