module Gyehoek.Test.CPS.Stackify (root) where

import Test.Tasty (TestTree, testGroup)
import Test.Tasty.HUnit
import qualified Gyehoek.CPS.Stackify as Sut
import Gyehoek.Stack.VM as Stk
import Data.List (List)
import Gyehoek.CPS.Syntax (cps)
import Gyehoek.GenSym (runGenSym)
import Effectful


root :: IO TestTree
root = pure . testGroup "stackify" $
  [ trivialReturn
  , tailCall
  , prim
  ]

evalsTo :: List Obj -> Sut.Exp -> Assertion
evalsTo rs e =
  Stk.eval e' @?= rs
  where e' = runPureEff . runGenSym $ Sut.stackifyExp "main" e

trivialReturn = testGroup "trivial return"
  [ testCase "return int" do
      evalsTo [ObjImm (ImmInt 4)]
        [cps|(continue halt 4)|]
  , testCase "return bool" do
      evalsTo [ObjImm (ImmBool True)]
        [cps|(continue halt #t)|]
      evalsTo [ObjImm (ImmBool False)]
        [cps|(continue halt #f)|]
  ]

tailCall = testGroup "tail call"
  [ testCase "square" do
      evalsTo [ObjImm (ImmInt 16)]
        [cps|(letrec ((square (λ (x ktail)
                                (prim (* x x)
                                  (κ (x0) (continue ktail x0))))))
               (square 4 halt))|]
  ]

prim = testGroup "prim"
  [ testCase "multiply" do
      evalsTo [ObjImm (ImmInt 20)]
        [cps|(prim (* 4 5)
               (κ (x) (continue halt x)))|]
  , testCase "add" do
      evalsTo [ObjImm (ImmInt 9)]
        [cps|(prim (+ 4 5)
               (κ (x) (continue halt x)))|]
  ]