П
replaceAt : Fin len -> elem -> Vect len elem -> Vect len elem
replaceAt FZ y (_::xs) = y :: xs
replaceAt (FS k) y (x::xs) = x :: replaceAt k y xs
типа вот это уже стрёмно
Size: a a a
П
B
AN
replaceAt : Fin len -> elem -> Vect len elem -> Vect len elem
replaceAt FZ y (_::xs) = y :: xs
replaceAt (FS k) y (x::xs) = x :: replaceAt k y xs
AN

П
П
AN
AN
AN
r
DS
TK
TK
DS
B
DS
B