[Haskell] View patterns in GHC: Request for feedback
Andreas-Haskell at gmx.net
Tue Jul 24 19:20:09 EDT 2007
I find that the suggested view pattern produce quite obfuscated code!
I guess it sets the language barrier quite a bit higher.
Do you really think a normal progrogrammer understands:
insert x s@(has x -> Just _) = s
fib (np 2 -> Just n) = fib (n + 1) + fib n
fib (np 2 => n) = fib (n + 1) + fib n
Do you really know what
fun f z  = z
fun f z (x : fun f z -> xs) = x `f` xs
I find it really hides the most important fact that fun is recursive.
(If you didn't recognize fun: it is foldr.)
I didn't see 1 convincing excample for the "need" of view pattern in that
paper and I didn't read the other proposals.
----- Original Message -----
From: "Dan Licata" <drl at cs.cmu.edu>
To: <haskell at haskell.org>
Sent: Monday, July 23, 2007 11:09 AM
Subject: [Haskell] View patterns in GHC: Request for feedback
> Hi everyone,
> Simon PJ and I are implementing view patterns, a way of pattern matching
> against abstract datatypes, in GHC. Our design is described here:
> If you have any comments or suggestions about this design, we'd love to
> hear them. You can respond to this list (and we can take it to
> haskell-cafe if the thread gets long) or, if you prefer, directly to me.
> Haskell mailing list
> Haskell at haskell.org
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