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module Builtins where
import Code
( Builtin(..)
, Cho(..)
, Datum(..)
, Dereferenced(..)
, Heap(..)
, Instr(..)
, Interp(..)
, InterpFn
, InterpFn
, derefHeap
, heapStruct
)
import qualified Compiler as Co
import Control.Monad.IO.Class (liftIO)
import Control.Monad.Trans.Class (lift)
import Control.Monad.Trans.State.Lazy (get, gets, modify)
import Data.Functor.Identity (runIdentity)
import Data.List (intercalate)
import qualified Data.Map as M
import Env (PrlgEnv(..), findAtom, findStruct, prlgError)
import qualified IR
import Interpreter (backtrack)
import qualified Operators as O
import System.Console.Haskeline (getInputChar, outputStr, outputStrLn)
bi = Builtin
showTerm itos heap = runIdentity . heapStruct atom struct hrec heap
where
atom (Atom a) = pure $ itos M.! a
atom VoidRef = pure "_"
struct (Struct (IR.Id h _)) args =
pure $ itos M.! h ++ "(" ++ intercalate "," args ++ ")"
hrec (HeapRef hr) ref =
pure $
(if hr == ref
then "_X"
else "_Rec") ++
show hr
printLocals :: InterpFn
printLocals = do
scope <- gets (gvar . cur)
heap <- gets (heap . cur)
IR.StrTable _ _ itos <- gets strtable
flip traverse (M.assocs scope) $ \(local, ref) ->
lift . outputStrLn $
"_Local" ++ show local ++ " = " ++ showTerm itos heap ref
return Nothing
promptRetry :: InterpFn
promptRetry = do
last <- gets (null . cho)
if last
then return Nothing
else promptRetry'
promptRetry' :: InterpFn
promptRetry' = do
x <- lift $ getInputChar "? "
case x of
Just ';' -> backtrack
_ -> return Nothing
withArgs :: [Int] -> ([Int] -> InterpFn) -> InterpFn
withArgs as f = do
scope <- gets (hvar . cur)
if all (`M.member` scope) as
then f $ map (scope M.!) as
else prlgError "arguments not bound"
write' :: InterpFn -> InterpFn
write' c =
withArgs [0] $ \[arg] -> do
heap <- gets (heap . cur)
IR.StrTable _ _ itos <- gets strtable
lift . outputStr $ showTerm itos heap arg
c --this now allows error fallthrough but we might like EitherT
write = write' $ return Nothing
nl :: InterpFn
nl = do
lift $ outputStrLn ""
return Nothing
writeln :: InterpFn
writeln = write' nl
assertFact :: InterpFn
assertFact =
withArgs [0] $ \[arg] -> do
heap <- gets (heap . cur)
case Co.compileGoal . Co.squashVars <$>
Co.heapStructPrlgInt Nothing heap arg of
Just (U (Struct s):head) -> do
addClause s $ head ++ [NoGoal]
return Nothing
_ -> prlgError "assert fact failure"
assertClause :: InterpFn
assertClause =
withArgs [0, 1] $ \args -> do
scope <- gets (hvar . cur)
heap <- gets (heap . cur)
comma <- findAtom ","
cut <- findAtom "!"
case Co.squashVars . IR.CallI 0 <$>
traverse (Co.heapStructPrlgInt Nothing heap) args of
Just (IR.CallI 0 [hs, gs]) ->
let (U (Struct s):cs) =
Co.compileGoal hs ++ Co.seqGoals (Co.compileGoals comma cut gs)
in do addClause s cs
return Nothing
_ -> prlgError "assert clause failure"
retractall :: InterpFn
retractall =
withArgs [0] $ \[arg] -> do
heap <- gets (heap . cur)
case derefHeap heap arg of
BoundRef _ (Atom a) -> dropProcedure (IR.Id {IR.arity = 0, IR.str = a})
BoundRef _ (Struct id) -> dropProcedure id
_ -> prlgError "retractall needs a struct"
call :: InterpFn
call =
withArgs [0] $ \[arg] -> do
heap@(Heap _ hmap) <- gets (heap . cur)
let exec base struct arity = do
cur <- gets cur
modify $ \s ->
s
{ cur =
cur
{ gol =
[Call, Goal, U struct] ++
[U $ hmap M.! (base + i) | i <- [1 .. arity]] ++ gol cur
}
}
return Nothing
case derefHeap heap arg of
BoundRef addr struct@(Struct IR.Id {IR.arity = arity}) ->
exec addr struct arity
BoundRef addr (Atom a) ->
exec addr (Struct IR.Id {IR.arity = 0, IR.str = a}) 0
_ -> prlgError "not callable"
struct :: InterpFn
struct = do
scope <- gets (hvar . cur)
prlgError "not yet"
{- adding the builtins -}
addOp op = modify $ \s -> s {ops = op : ops s}
addClause struct code =
modify $ \s ->
s {defs = M.alter (Just . maybe [code] (\hs -> code : hs)) struct $ defs s}
addProcedure struct heads =
modify $ \s -> s {defs = M.insert struct heads $ defs s}
dropProcedure struct = do
d <- gets defs
if struct `M.member` d
then do
modify $ \s -> s {defs = M.delete struct d}
return Nothing
else prlgError "no such definition" -- this should backtrack?
addProc n a c = do
sym <- findStruct n a
addProcedure sym c
addBi n i b =
addProc n i [[U (LocalRef $ r - 1) | r <- [1 .. i]] ++ [Invoke $ bi b]]
addPrelude :: PrlgEnv ()
addPrelude = do
pure undefined
{- primitives -}
addBi "true" 0 (pure Nothing)
addBi "fail" 0 backtrack
addOp $ O.xfx "=" 700
addProc "=" 2 [[U (LocalRef 0), U (LocalRef 0), NoGoal]]
{- clauses -}
addOp $ O.xfy "," 1000
addOp $ O.xfx ":-" 1200
horn2 <- findStruct ":-" 2
--addOp $ O.fx ":-" 1200
addProc
"assert"
1
[ [ U (Struct horn2)
, U (LocalRef 0)
, U (LocalRef 1)
, Cut
, Invoke (bi assertClause)
]
, [U (LocalRef 0), Invoke (bi assertFact)]
]
addBi "retractall" 1 retractall
addBi "call" 1 call
addBi "struct" 3 struct
{- query tools -}
addBi "print_locals" 0 printLocals
addBi "prompt_retry" 0 promptRetry'
addBi "query" 0 (printLocals >> promptRetry)
{- IO -}
addBi "write" 1 write
addBi "writeln" 1 writeln
addBi "nl" 0 nl
{- debug -}
addBi "interpreter_trace" 0 (get >>= liftIO . print >> pure Nothing)
|
