import Clash.Prelude
-- import Clash.Explicit.Testbench

data SList a
  = SNil
  | SCons !a !(SList a)
  deriving (NFDataX, Generic)

isSNil :: SList a -> Bool
isSNil sl = case sl of
  SNil -> True
  _ -> False

tf :: SList Int -> Int -> (SList Int, Maybe Bool)
tf s inp = case s of
  SCons _ s' -> (s', Just False)
  SNil -> (SNil, Just True)

mon
  :: SystemClockResetEnable
  => Signal System Int
  -> Signal System (Maybe Bool)
mon = mealy tf SNil

topEntity
  :: Clock System
  -> Reset System
  -> Enable System
  -> Signal System Int
  -> Signal System (Maybe Bool)
topEntity = exposeClockResetEnable mon

{-

GHC: Setting up GHC took: 0.662s
GHC: Compiling and loading modules took: 1.062s
Clash: Parsing and compiling primitives took 0.176s
GHC+Clash: Loading modules cumulatively took 2.192s
Clash: Compiling Main.topEntity
Clash.Normalize.Transformations.Inline(523): InlineNonRep: c$Main.mon_ds[19] already inlined 20 times in: Main.mon[8214565720323816306]
. The type of the subject is:

  GHC.Tuple.(,)[3746994889972252676]
    (Main.SList[8214565720323816301]
       GHC.Types.Int[3674937295934324766])
    (GHC.Maybe.Maybe[3674937295934324792]
       GHC.Types.Bool[3674937295934324744])

Function Main.mon[8214565720323816306] will not reach a normal form and compilation 
might fail.

Run with '-fclash-inline-limit=N' to increase the inline limit to N.
Clash.Normalize.Transformations.Inline(523): InlineNonRep: c$Main.mon_ds[19] already inlined 20 times in: Main.mon[8214565720323816306]
. The type of the subject is:

  GHC.Tuple.(,)[3746994889972252676]
    (Main.SList[8214565720323816301]
       GHC.Types.Int[3674937295934324766])
    (GHC.Maybe.Maybe[3674937295934324792]
       GHC.Types.Bool[3674937295934324744])

Function Main.mon[8214565720323816306] will not reach a normal form and compilation 
might fail.

Run with '-fclash-inline-limit=N' to increase the inline limit to N.
Clash.Normalize.Transformations.Inline(523): InlineNonRep: c$Main.mon_ds[19] already inlined 20 times in: Main.mon[8214565720323816306]
. The type of the subject is:

  GHC.Tuple.(,)[3746994889972252676]
    (Main.SList[8214565720323816301]
       GHC.Types.Int[3674937295934324766])
    (GHC.Maybe.Maybe[3674937295934324792]
       GHC.Types.Bool[3674937295934324744])

Function Main.mon[8214565720323816306] will not reach a normal form and compilation 
might fail.

Run with '-fclash-inline-limit=N' to increase the inline limit to N.

<no location info>: error:
    Clash error call:
    Clash.Core.Type(395): Report as bug: not a FunTy
    CallStack (from HasCallStack):
      error, called at src/Clash/Core/Type.hs:395:20 in clash-lib-1.6.3-4vM2gwSsWPHufxjlmfu4S:Clash.Core.Type

-}