[Haskell-cafe] How to express a logic matrix clearly?
tom-lists-haskell-cafe-2017 at jaguarpaw.co.uk
Fri May 17 09:37:20 UTC 2019
On Thu, May 16, 2019 at 10:21:14PM -0500, Nathan Bloomfield wrote:
> This is a good opportunity to use case syntax. You can also case on tuples,
> like this:
> foo a b = case (a,b) of
> (A1,B1) -> fun1
> (A1,B2) -> fun2
> (A1,B3) -> fun3
> (A1,_) -> fun4 <- this is probably not necessary anymore, unless you
> expect Rule2 to get more constructors.
> (A2,B1) -> fun5
In fact, and this is veering somewhat off-topic, but I would strongly
recommend *not* making a default match `(A1,_)` because then you will get an
explicit warning if indeed `Rule2` gets more constructors.
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