-- AG Test File

{
module Example where
}

{
data Expr
  = Plus Expr Expr
  | Const Int
  | Funny
}

interface Eval
  visit select
    inputs  e :: {Expr}
  visit compute
    outputs v :: {Int}
  visit funny
    outputs z :: {Char}

{
eval_expr =
 {{ sem :: Eval
      production
        visit select
          clause
            match { Const @loc.x } = { @lhs.e }
        visit compute
          clause
            eval  { @lhs.v       } = { @loc.x }
        visit funny
          clause
            eval  { @lhs.z       } = { 'a' }

      production
        visit select
          clause
            match { Plus @loc.e1 @loc.e2 } = { @lhs.e }

        visit compute
          clause
            child k1 :: Eval   = { eval_expr }
            child k1 : select  = { id }
            child k1 : compute = { id}
            
            child k2 :: Eval   = { eval_expr }
            child k2 : select  = { id }
            child k2 : compute = { id }

            eval { @k1.e}    = { @loc.e1 }
            eval { @k2.e}    = { @loc.e2 }
            eval { @lhs.v }  = { @k1.v + @k2.v }
        
        visit funny
          clause
            eval { @lhs.z }  = { 'b' }
      
      production
        visit select
          clause
        visit compute
          external { Just (Eval_funny (Just 'c'), 2) }
        
        visit funny
 }}


main = let e   = Plus (Plus (Const 1) (Const 2)) (Const 3)
           inh = Inh_Eval_select { e_Inh_Eval_select = e }
           syn = wrap_Eval_select eval_expr inh
           v   = v_Syn_Eval_select syn
           z   = z_Syn_Eval_select syn
       in putStrLn (z : show v)
}