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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