Chaitin's construction/Combinatory logic

Combinatory logic term modules

CL

 module CL (CL, k, s, apply) where

 import Tree (Tree (Leaf, Branch))
 import BaseSymbol (BaseSymbol, kay, ess)

 type CL = Tree BaseSymbol 

 k, s :: CL
 k = Leaf kay
 s = Leaf ess

 apply :: CL -> CL -> CL
 apply = Branch

CL extension

 module CLExt ((>>@)) where

 import CL (CL, apply)
 import Control.Monad (Monad, liftM2)

 (>>@) :: Monad m => m CL -> m CL -> m CL
 (>>@) = liftM2 apply

Base symbol

 module BaseSymbol (BaseSymbol, kay, ess) where

 data BaseSymbol = K | S

 kay, ess :: BaseSymbol
 kay = K
 ess = S