SMT.hs

{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE UndecidableInstances #-}

{- |
This module provides a concrete implementation for 'MonadSMT' with it's state 'SMT'.
-}
module Language.Hasmtlib.Type.SMT
(
  -- * Type
  SMT(..)

  -- * Lens
, lastVarId, vars, formulas
, mlogic, options
, sharingMode, Language.Hasmtlib.Type.SMT.stableMap
)
where

import Language.Hasmtlib.Internal.Sharing
import Language.Hasmtlib.Type.MonadSMT
import Language.Hasmtlib.Type.SMTSort
import Language.Hasmtlib.Type.Option
import Language.Hasmtlib.Type.Expr
import Data.List (isPrefixOf)
import Data.Default
import Data.Coerce
import Data.Sequence hiding ((|>), filter)
import Data.HashMap.Lazy (HashMap)
import Control.Monad.State
import Control.Lens hiding (List)
import System.Mem.StableName

-- | The state of the SMT-problem.
data SMT = SMT
  { _lastVarId :: {-# UNPACK #-} !Int                                 -- ^ Last Id assigned to a new var
  , _vars      :: !(Seq (SomeKnownSMTSort SMTVar))                    -- ^ All constructed variables
  , _formulas  :: !(Seq (Expr BoolSort))                              -- ^ All asserted formulas
  , _mlogic    :: Maybe String                                        -- ^ Logic for the SMT-Solver
  , _options   :: [SMTOption]                                         -- ^ All manually configured SMT-Solver-Options
  , _sharingMode :: !SharingMode                                       -- ^ How to share common expressions
  , _stableMap :: !(HashMap (StableName ()) (SomeKnownSMTSort Expr))  -- ^ Mapping between a 'StableName' and it's 'Expr' we may share
  }
$(makeLenses ''SMT)

instance Default SMT where
  def = SMT 0 mempty mempty mempty [ProduceModels True] def mempty

instance Sharing SMT where
  type SharingMonad SMT = Monad
  stableMap = Language.Hasmtlib.Type.SMT.stableMap
  assertSharedNode _ expr = modifying formulas (|> expr)
  setSharingMode sm = sharingMode .= sm

instance MonadState SMT m => MonadSMT SMT m where
  smtvar' _ = fmap coerce $ lastVarId <+= 1
  {-# INLINE smtvar' #-}

  var' p = do
    newVar <- smtvar' p
    vars %= (|> SomeSMTSort newVar)
    return $ Var newVar
  {-# INLINEABLE var' #-}

  assert expr = do
    smt <- get
    sExpr <- runSharing (smt^.sharingMode) expr
    qExpr <- case smt^.mlogic of
      Nothing    -> return sExpr
      Just logic -> if "QF" `isPrefixOf` logic then return sExpr else quantify sExpr
    modify $ \s -> s & formulas %~ (|> qExpr)
  {-# INLINE assert #-}

  setOption opt = options <>= pure opt

  setLogic l = mlogic ?= l