def recursive(base, extend, max_leaves=100):
"""
base: A strategy to start from
extend: A function which takes a strategy and returns a new strategy
max_leaves: The maximum number of elements to be drawn from base on a given
run.
This returns a strategy S such that S = extend(base | S). That is, values
maybe drawn from base, or from any strategy reachable by mixing
applications of | and extend.
An example may clarify: recursive(booleans(), lists) would return a
strategy that may return arbitrarily nested and mixed lists of booleans.
So e.g. False, [True], [False, []], [[[[True]]]], are all valid values to
be drawn from that strategy.
"""
check_strategy(base)
extended = extend(base)
if not isinstance(extended, SearchStrategy):
raise InvalidArgument(
u'Expected extend(%r) to be a SearchStrategy but got %r' % (
base, extended
))
from hypothesis.searchstrategy.recursive import RecursiveStrategy
return RecursiveStrategy(base, extend, max_leaves)
def recursive(base, extend, max_leaves=100):
"""base: A strategy to start from.
extend: A function which takes a strategy and returns a new strategy.
max_leaves: The maximum number of elements to be drawn from base on a given
run.
This returns a strategy S such that S = extend(base | S). That is, values
maybe drawn from base, or from any strategy reachable by mixing
applications of | and extend.
An example may clarify: recursive(booleans(), lists) would return a
strategy that may return arbitrarily nested and mixed lists of booleans.
So e.g. False, [True], [False, []], [[[[True]]]], are all valid values to
be drawn from that strategy.
"""
from hypothesis.searchstrategy.recursive import RecursiveStrategy
return RecursiveStrategy(base, extend, max_leaves)
