This is what I was going to say. The original poster is right, but still, null is a function. It is one level of indirection away from pattern matching.
On Tuesday, April 16, 2024 at 10:46:56 AM EDT, Henning Thielemann
ghc should be able to deduce correct use of partial functions and not give a warning in such cases, e.g. in 9.8.2
if null ys then [] else [(xs,tail ys)])
gets a warning
warning: [GHC-63394] [-Wx-partial]
but it is clear that this use of tail will never be a problem so IMHO that line of code should not get a warning.
Does anybody know if there is a plan or enhancement request to eliminate such warnings?
I would just use good old pattern matching: case ys of [] -> [] _:zs -> [(xs,zs)]_______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.