6 May
2010
6 May
'10
4:50 a.m.
So the good news is that quickcheck 2.1 behaves as I expected. I'm still curious as to the behaviour of the older version.
In QC 1.2, the instance of Arbitrary for the Maybe type uses the "sized" combinator to choose between Nothing and Just, whereas in QC 2.1, the instance uses the "frequency" combinator. I'm guessing that the notion of size applies to the whole enclosing value, so gets replicated to all of its parts, whereas frequency is independently generated for each component. Regards, Malcolm