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|
module Stackless ( generate )
where
import Atom
import Haskell
import Grammar hiding ( prec )
import qualified Grammar as G
import Convert
import LR0 hiding ( fromList )
import Case
import qualified OrdUniqListSet as Set
import qualified SearchTree as ST
import Options
import Base
import Generate
import MergeSort
import Char
import Maybe
import IO
import Monad
import Prelude hiding ( lookup )
safeLookup :: (Show a, Ord a) => ST.FM a v -> a -> v
safeLookup fm a = fromMaybe (error ("not found: " ++ show a)) (ST.lookup fm a)
data Branch' = Shift1' Symbol State
| ReduceN' [Int]
| ShiftReduce' Symbol State Branch'
| ReduceReduce' [Int] -- reduce/reduce conflict
| TokenCase' [(Symbol, Branch')] [Branch']
deriving (Eq, Ord, Show)
branch' :: Branch -> Branch'
branch' (Shift1 (_s, v, s')) = Shift1' v s'
branch' (ReduceN as) = ReduceN' (map pnumber as)
branch' (ShiftReduce (_s, v, s') b)
= ShiftReduce' v s' (branch' b)
branch' (ReduceReduce as) = ReduceReduce' (map pnumber as)
branch' (TokenCase es bs _la) = TokenCase' [ (v, branch' b) | (v, b) <- es ] [ branch' b | b <- bs ]
codeLeq (s1, _b1) (s2, _b2) = rests s1 <= rests s2
codeEqu (s1, _b1) (s2, _b2) = rests s1 == rests s2
rests s = mergeSort (map iinput (toList (items s)))
generate :: [Flag] -> Grammar -> [(Symbol, State)] -> GotoTable -> BranchTable -> IO [Decl]
generate opts grammar entries edges table
= do verb "* Generating Haskell code ... (--code=stackless)"
when backtrFlag (warning "--backtrack is not supported")
when trFlag (warning "--trace is not supported")
verb (" identical states: " ++ show [ map (snumber . fst) g | g <- groupedTable, length g > 1 ])
return decls
where
verb = verbose opts
decls = (if sigFlag then
[ TypeDecl parser_type ([x_tcon] <->>
result_tcon <$> [if Signature False `elem` opts then nonterminal_tcon else t_var])
, Empty ]
++ (if Signature False `elem` opts then
[ DataDecl nonterminal_tcon
[ (unCon (ntName n), typesOf n) | (n, _) <- entries ]
, Empty ]
else
[])
else
[])
++ [ funbind (globalNTName n <$> [tr_var | not lexFlag])
(if Signature False `elem` opts then
(next_n s [Fun (genVars n ++ [anon])
(hsReturn <$> [ntName n <$> genVars n])]) <>>=>
Fun [ntName n <$> genVars n]
(hsReturn <$> [Tuple (genVars n)])
else
(next_n s [Fun (genVars n ++ [anon])
(hsReturn <$> [Tuple (genVars n)])]))
| (n, s) <- entries ]
++ concat [ Empty
-- : AComment ["state " ++ show (snumber s) ++ reportConflicts cases ++ " "]
: genState_n s cases
| (s, cases) <- ST.toList table, not (isIdState s) ]
-- | (s, cases) <- mergeSort (map head groupedTable), not (isIdState s) ]
++ concat [ [ Empty ]
++ [ AComment ["# NOINLINE " ++ string (unVar red) ++ " #"] | noinline ]
++ [ Sig [unVar red] (((typesOf (rlhs r) <->> parser_type)
: concat [ typesOf v | v <- rrhs r ]) <->> parser_type)
| sigFlag ]
++ [funbind (red <$> ([g_var] ++ concat [ argsOf v | v <- rrhs r ] ++ [ts_var]))
(evaluate (argsOf (rlhs r)) (\ args -> g_var <$> (args ++ [ts_var])))]
| r <- productions grammar
, not (isPrimed (name (rlhs r)))
, let red = reduce_var (rnumber r) ]
-- ++ [ Empty
-- , funbind (notpossible x_var) (
-- hsFail <$> [stringLiteral "\"The `impossible' happened.\""])]
k = lookahead opts
trFlag = Trace `elem` opts
lexFlag = Lexer `elem` opts
expFlag = Expected `elem` opts
backtrFlag = Backtrack `elem` opts
sigFlag = Signature False `elem` opts || Signature True `elem` opts
noinline = Noinline `elem` opts
optimize = Optimize `elem` opts
x_var = if lexFlag then t_var else ts_var
x_tcon = if lexFlag then terminal_tcon else List [terminal_tcon]
idStates = ST.fromList [ (s, isId cases) | (s, cases) <- ST.toList table ]
isIdState s = optimize && safeLookup idStates s
isId (ReduceN as) = equal (map pnumber as) && stack (head as) /= Nil
isId _ = False
groupedTable = groupBy codeEqu (mergeSortBy codeLeq (ST.toList table))
codeEquState = ST.fromList [ (s, fst (head g)) | g <- groupedTable, (s, _) <- g ]
state_n s ks
| isIdState s = head ks
| otherwise = state_var s <$> ks
-- | otherwise = state_var (safeLookup codeEquState s) <$> ks
genState_n s cases
= [ Sig [unVar (state_var s)] ([ k_type i | i <- Set.toList q ] <->> parser_type)
| sigFlag]
++ [ funbind (state_n s [ k_var i | i <- Set.toList q ] <$> [x_var])
(local [ funbind (goto_var v <$> (genVars v)) --(argsOf v))
(state_n s2 [ kernel i <$> (genVars v) | i <- itemsOf v ])
| (s1, v, s2) <- edges, s1 == s, nonterminal v ]
(genBody cases))]
where
q :\/ _q' = items s
k_type i = concat [ typesOf v | v <- iinput i ] <->> parser_type
genBody (ReduceN as)
| equal (map pnumber as)
= kernel' (head as) <$> [x_var]
| otherwise = error ("the grammar is not LALR(" ++ show k ++ ")")
genBody (TokenCase es bs la)
= switch x_var ([ (genPat t, genExpr e (genVars t))
| (t, e) <- es ]
++ [(anon, if null bs then
frown la
else
genExpr (head bs) [])])
genBody _ = impossible "Stackless.genBody"
itemsOf v = [ item | item@(Item i n l (v' : r) a) <- LR0.toList (items s), v' == v ]
kernel i
| i `Set.elem` q = k_var i
| otherwise = reduce_var (inumber i) <$> [goto_var (ilhs i)]
kernel' a
| stack a /= Nil = k_var' a
| otherwise = reduce_var (pnumber a) <$> [let (_, n, _) = goto a in goto_var n]
genExpr (Shift1 (_s, t, s')) vs
| modifier t == Insert
= state_n s' [ kernel i | i <- itemsOf t ] <$> [x_var] -- NB `|t|' must not have semantic values
| otherwise = next_n s' [ kernel i <$> vs | i <- itemsOf t ]
genExpr (ReduceN rs) _vs
| equal (map pnumber rs)
= kernel' (head rs) <$> [x_var]
| otherwise = error ("the grammar is not LALR(" ++ show k ++ ")")
genExpr (ShiftReduce e _b) vs
= genExpr (Shift1 e) vs -- select shift (for the moment)
genExpr (ReduceReduce rs) vs
= genExpr (ReduceN [head rs]) vs
genExpr (TokenCase [] bs la) _vs -- HACK: for empty `case' that simulates `fail'
= if null bs then
frown la
else
genExpr (head bs) []
genExpr (TokenCase es bs la) _vs -- does not work with a monadic lexer
= switch tr_var ([ (genPat t, genExpr e [])
| (t, e) <- es ]
++ [(anon, if null bs then
frown la
else
genExpr (head bs) [])])
--impossible "Stackless.genExpr"
genPat v
| lexFlag = fresh v
| isNewEOF (pattern v)= asPat tr_var hsNil
| otherwise = fresh v <:> tr_var
next_n s ks
| lexFlag = hsGet <>>=> state_n s ks
| otherwise = state_n s ks <$> [tr_var]
frown la
| expFlag = hsFrown <$> [expected la, x_var]
| otherwise = hsFrown <$> [x_var]
{-
FunBind lhs rhs <||> alt = FunBind lhs (rhs <|> alt)
e1 <|> e2
| backtrFlag = Infix e1 "`mplus`" e2
| otherwise = e1
-}
-- notpossible ts = impossible_var <$> [ts]
state_var s = wrap_var ("state_" ++ smangle s)
k_var i = wrap_var ("k_" ++ imangle i ++ "_" ++ show (length (list (istack i))))
k_var' a = wrap_var ("k_" ++ show (pnumber a) ++ "_" ++ show (length (list (stack a))))
goto_var v = wrap_var ("goto_" ++ vmangle 1 v)
reduce_var i = wrap_var ("reduce_" ++ show i)
ts_var = wrap_var "ts"
tr_var = wrap_var "tr"
t_var = wrap_var "t"
g_var = wrap_var "g"
nonterminal_tcon = wrap_con "Nonterminal"
-- impossible_var = wrap_var "impossible"
parser_tcon = wrap_con "Parser"
parser_type
| Signature False `elem` opts
= parser_tcon
| otherwise = parser_tcon <$> [t_var]
globalNTName v = var (string (name v))
ntName v = wrap_con (string (name v))
wrap s = prefix opts ++ s ++ suffix opts
wrap_var s = var (wrap s)
wrap_con s = con (wrap s)
|
