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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.elems scope) $ \(ref, name) ->
lift . outputStrLn $
(maybe "_" id $ itos M.!? name) ++ " = " ++ 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
write :: InterpFn
write
--TODO: prlgError on write(Unbound)
= do
scope <- gets (hvar . cur)
heap <- gets (heap . cur)
IR.StrTable _ _ itos <- gets strtable
lift . outputStr . showTerm itos heap . fst $ scope M.! 0
return Nothing
nl :: InterpFn
nl = do
lift $ outputStrLn ""
return Nothing
writeln :: InterpFn
writeln = write >> nl
assertFact :: InterpFn
assertFact = do
scope <- gets (hvar . cur)
heap <- gets (heap . cur)
case Co.compileGoal . Co.squashVars <$>
Co.heapStructPrlgInt Nothing heap (fst $ scope M.! 0) of
Just (U (Struct s):head) -> do
addClause s $ head ++ [NoGoal]
return Nothing
_ -> prlgError "assert fact failure"
assertClause :: InterpFn
assertClause = do
scope <- gets (hvar . cur)
heap <- gets (heap . cur)
commaId <- findStruct "," 2
cut <- findAtom "!"
case Co.squashVars . IR.CallI (IR.Id 0 0) <$>
traverse (Co.heapStructPrlgInt Nothing heap . fst . (M.!) scope) [0, 1] of
Just (IR.CallI (IR.Id 0 0) [hs, gs]) ->
let (U (Struct s):cs) =
Co.compileGoal hs ++ Co.seqGoals (Co.compileGoals commaId cut gs)
in do addClause s cs
return Nothing
_ -> prlgError "assert clause failure"
retractall :: InterpFn
retractall = prlgError "no retractall yet"
call :: InterpFn
call = do
ref <- gets (fst . (M.! 0) . hvar . cur)
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 ref 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"
{- 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}
addProc n a c = do
sym <- findStruct n a
addProcedure sym c
addBi0 n b = addProc n 0 [[Invoke $ bi b]]
addPrelude :: PrlgEnv ()
addPrelude = do
pure undefined
{- primitives -}
addBi0 "true" (pure Nothing)
addBi0 "fail" backtrack
addOp $ O.xfx "=" 700
addProc "=" 2 [[U (LocalRef 0 0), U (LocalRef 0 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 0)
, U (LocalRef 1 0)
, Cut
, Invoke (bi assertClause)
]
, [U (LocalRef 0 0), Invoke (bi assertFact)]
]
addProc "retractall" 1 [[U (LocalRef 0 0), Invoke (bi retractall)]]
addProc "call" 1 [[U (LocalRef 0 0), Invoke (bi call)]]
{- query tools -}
addBi0 "print_locals" printLocals
addBi0 "prompt_retry" promptRetry'
addBi0 "query" (printLocals >> promptRetry)
{- IO -}
addProc "write" 1 [[U (LocalRef 0 0), Invoke (bi write)]]
addProc "writeln" 1 [[U (LocalRef 0 0), Invoke (bi writeln)]]
addBi0 "nl" nl
{- debug -}
addBi0 "interpreter_trace" (get >>= liftIO . print >> pure Nothing)
|
