You're missing the parens around (x:yx) in the last clause.
On Tue, 12 May 2015 at 11:02 Roelof Wobben
Hello,
I try to re implement ++
So far I have this ;
plusplus' :: [a] -> [a] -> [a] plusplus' [] (xs) = xs plusplus' [] [] = [] plusplus' (xs) [] = xs plusplus' (x:xs) yx = plusplus' xs x:yx
main = print . plusplus' $ [1,2] [3,4]
But I still get this error message :
src/Main.hs@5:23-5:37 Couldn't match expected type a with actual type [a] a is a rigid type variable bound by the type signature for plusplus' :: [a] -> [a] -> [a] at /home/app/isolation-runner-work/projects/112825/session.207/src/src/Main.hs:1:14 Relevant bindings include yx :: [a] (bound at /home/app/isolation-runner-work/projects/112825/session.207/src/src/Main.hs:5:18) xs :: [a] (bound at /home/app/isolation-runner-work/projects/112825/session.207/src/src/Main.hs:5:14) x :: a (bound at /home/app/isolation-runner-work/projects/112825/session.207/src/src/Main.hs:5:12) plusplus' :: [a] -> [a] -> [a] (bound at /home/app/isolation-runner-work/projects/112825/session.207/src/src/Main.hs:2:1) …
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