[Haskell-cafe] Re: QuickCheck [Architecturally flawed]

Andrew Coppin andrewcoppin at btinternet.com
Sun Jul 13 15:49:43 EDT 2008

Ryan Ingram wrote:
> I think you can use the duality of Writer/Reader to help you here; you
> have the law that, for suitable "dual" computations r and w,
> run_reader r (run_writer (w x)) == x
> Then you can build up a list of rules specifying which computations
> are dual; read64 is dual to write64, for example.

OK. This is more or less the approach I ended up taking. Otherwise the 
QuickCheck properties just reimplement the functions themselves - which 
doesn't tell you anything! ;-)

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