[Haskell-cafe] QuickCheck Arbitrary - infinite recursion on
marco-oweber at gmx.de
Mon Jun 4 22:40:20 EDT 2007
data A = A INt
| B [A]
instace Arbitrary A where
arbitrary = oneof [ liftM A arbitrary
, liftM B arbitrary
But now QuickCheck will propably create a test value
A ( B [ A ( B [ A .... -> no end
Is there an easy QuickCheck way to prevent this?
I can think of:
a) using sized to pass when to stop (decrement the value ..)
b) using some type hackary
data Recursive a = R a
then use arbitrary :: R ( R ( a ))
and remove one R each time..
c) pass a recursion indicator manually and decrement that...
Which would you choose?
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