[Haskell-cafe] Test.QuickCheck: generate

Paul Johnson paul at cogito.org.uk
Thu Oct 8 12:15:46 EDT 2009

On 08/10/09 04:57, David Menendez wrote:
> On Wed, Oct 7, 2009 at 8:29 PM, Michael Mossey<mpm at alumni.caltech.edu>  wrote:
>> In Test.QuickCheck, the type of 'generate' is
>> generate :: Int ->  StdGen ->  Gen a ->  a
>> I can't find docs that explain what the Int does. Some docs are here:
> Judging by the source code, the integer is the upper bound for the
> size parameter. If you are generating a list, for example, it gives
> the maximum size of the list
Thats right.  Its the "size" parameter, and what it does depends on the 
instance of Arbitrary.  Arbitrary numbers will be within +/- size.  
Arbitrary lists will be of maximum length size.  On the other hand 
arbitrary booleans will just be True or False.

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