Haskell tuple of duple type error

Question

i have this data type in haskell

type Coordinate = (Int,Int)
type Skyline = [Coordinate]

And im trying to do:

combina :: (Skyline, Skyline) -> Skyline
combina ([], x) = x
combina (x, []) = x
combina ((ii, ia):ri, (di, da):rd) = subcombina(((ii, ia):ri,0), (((di, da):rd),0), 0)
    where subcombina(((ii, ai):ri,uai), (((id, ad):rd),uad), uaa)
            | ai < ad && max(uai uad) /= uaa                      = (ii, max ai uad) : subcombina((ri,ai), ((id, ad):rd, uad), max(ai uad))
            | ai < ad && max(uai uad) == uaa                      =                    subcombina((ri,ai), ((id, ad):rd, uad), uaa)
            | ((ai > ad) || (ai == ad)) && max(uai uad) /= uaa    = (id, max uai ad) : subcombina(((ii, ai):ri,uai),(rd, ad), max (uai ad))
            | ((ai > ad) || (ai == ad)) && max (uai uad) /= uaa   =                    subcombina(((ii, ai):ri,uai),(rd, ad), uaa)

So, im trying to call to subcombina with

(((leftElementOfFirstLeftListTuple,rigthElementOfFirstLeftListTuple):restOfList,anyInteger),((leftElementOfFirstRigthListTuple,rigthElementOfFirsttRigthLListTuple):restOfList,anyInteger),
anyInteger)

And im getting this errors:

:l Skyline                                                                                                                                                                           
[1 of 1] Compiling Skyline          ( Skyline.hs, interpreted )

Skyline.hs:26:38:
    Couldn't match type ‘t0 -> a0’ with ‘Int’
    Expected type: Skyline
      Actual type: [(Int, t0 -> a0)]
    In the expression:
      subcombina (((ii, ia) : ri, 0), (((di, da) : rd), 0), 0)
    In an equation for ‘combina’:
        combina ((ii, ia) : ri, (di, da) : rd)
          = subcombina (((ii, ia) : ri, 0), (((di, da) : rd), 0), 0)
          where
              subcombina (((ii, ai) : ri, uai), (((id, ad) : rd), uad), uaa)
                | ai < ad && max (uai uad) /= uaa
                = (ii, max ai uad)
                  : subcombina ((ri, ai), ((id, ad) : rd, uad), max (ai uad))
                | ai < ad && max (uai uad) == uaa
                = subcombina ((ri, ai), ((id, ad) : rd, uad), uaa)
                | ((ai > ad) || (ai == ad)) && max (uai uad) /= uaa
                = (id, max uai ad)
                  : subcombina (((ii, ai) : ri, uai), (rd, ad), max (uai ad))
                | ((ai > ad) || (ai == ad)) && max (uai uad) /= uaa
                = subcombina (((ii, ai) : ri, uai), (rd, ad), uaa)

Skyline.hs:26:55:
    Couldn't match expected type ‘t0 -> a0’ with actual type ‘Int’
    In the expression: ia
    In the first argument of ‘(:)’, namely ‘(ii, ia)’

Skyline.hs:26:59:
    Couldn't match type ‘Int’ with ‘t0 -> a0’
    Expected type: [(Int, t0 -> a0)]
      Actual type: [Coordinate]
    In the second argument of ‘(:)’, namely ‘ri’
    In the expression: (ii, ia) : ri

Skyline.hs:26:73:
    Couldn't match expected type ‘t0 -> a0’ with actual type ‘Int’
    In the expression: da
    In the first argument of ‘(:)’, namely ‘(di, da)’

Skyline.hs:26:77:
    Couldn't match type ‘Int’ with ‘t0 -> a0’
    Expected type: [(Int, t0 -> a0)]
      Actual type: [Coordinate]
    In the second argument of ‘(:)’, namely ‘rd’
    In the expression: ((di, da) : rd)

Skyline.hs:28:103:
    Occurs check: cannot construct the infinite type: t1 ~ t1 -> a
    Expected type: (t1 -> a) -> a
      Actual type: t1 -> a
    Relevant bindings include
      uaa :: a -> a (bound at Skyline.hs:27:62)
      uad :: t1 -> a (bound at Skyline.hs:27:56)
      rd :: [(t, t1 -> a)] (bound at Skyline.hs:27:52)
      ad :: t1 -> a (bound at Skyline.hs:27:48)
      uai :: (t1 -> a) -> a (bound at Skyline.hs:27:35)
      ri :: [(t, t1 -> a)] (bound at Skyline.hs:27:32)
      (Some bindings suppressed; use -fmax-relevant-binds=N or -fno-max-relevant-binds)
    In the expression: ai
    In the expression: (ri, ai)
Failed, modules loaded: none.

I think i'm mixing types but i cannot found where.

Answer 1

You are attempting to call max using (among other things)

max(ai uad)

This says "Apply the function ai to the value uad and apply max to the result." You probably meant to use

max ai uad

Answer 2

You have something like

max (ai uad) 

in your code. This applies ai to uad But I guess what you wanted was simply:

max ai uad