def assert__(engine, obj, condition, message=u'Assertion failed'):
""":yaql:assert
Evaluates condition against object. If it evaluates to true returns the
object, otherwise throws an exception with provided message.
:signature: obj.assert(condition, message => "Assertion failed")
:arg obj: object to evaluate condition on
:argType obj: any
:arg condition: lambda function to be evaluated on obj. If result of
function evaluates to false then trows exception message
:argType condition: lambda
:arg message: message to trow if condition returns false
:argType message: string
:returnType: obj type or message
.. code::
yaql> 12.assert($ < 2)
Execution exception: Assertion failed
yaql> 12.assert($ < 20)
12
yaql> [].assert($, "Failed assertion")
Execution exception: Failed assertion
"""
if utils.is_iterator(obj):
obj = utils.memorize(obj, engine)
if not condition(obj):
raise AssertionError(message)
return obj
def memorize(collection, engine):
return utils.memorize(collection, engine)
def join(engine, collection1, collection2, predicate, selector):
collection2 = utils.memorize(collection2, engine)
for self_item in collection1:
for other_item in collection2:
if predicate(self_item, other_item):
yield selector(self_item, other_item)
def assert__(engine, obj, condition, message=u'Assertion failed'):
if utils.is_iterator(obj):
obj = utils.memorize(obj, engine)
if not condition(obj):
raise AssertionError(message)
return obj
