module APL.AST
  ( VName,
    Exp (..),
    printExp,
  )
where

type VName = String

data Exp
  = CstInt Integer
  | CstBool Bool
  | Add Exp Exp
  | Sub Exp Exp
  | Mul Exp Exp
  | Div Exp Exp
  | Pow Exp Exp
  | Eql Exp Exp
  | If Exp Exp Exp
  | Var VName
  | Let VName Exp Exp
  | Lambda VName Exp
  | Apply Exp Exp
  | TryCatch Exp Exp
  deriving (Eq, Show)

printExp :: Exp -> String
printExp (CstBool b)      = show b
printExp (CstInt i)       = show i
printExp (Add e1 e2)      = "("++(printExp e1)++" + "++(printExp e2)++")"
printExp (Mul e1 e2)      = "("++(printExp e1)++" * "++(printExp e2)++")"
printExp (Sub e1 e2)      = "("++(printExp e1)++" - "++(printExp e2)++")"
printExp (Div e1 e2)      = "("++(printExp e1)++" / "++(printExp e2)++")"
printExp (Pow e1 e2)      = "("++(printExp e1)++" ** "++(printExp e2)++")"
printExp (Eql e1 e2)      = "("++(printExp e1)++" == "++(printExp e2)++")"
printExp (If e1 e2 e3)    = "(if "++(printExp e1)++" then "++(printExp e2)++" else "++(printExp e3)++")"
printExp (Var var)        = var
printExp (Let var e1 e2)  = "(let "++var++" = "++(printExp e1)++" in "++(printExp e2)++")"
printExp (Lambda var e)   = "(\\"++var++" -> "++(printExp e)++")"
printExp (Apply e1 e2)    = "("++(printExp e1)++" "++(printExp e2)++")"
printExp (TryCatch e1 e2) = "(try "++(printExp e1)++" catch "++(printExp e2)++")"