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|
module GVStack ( generate )
where
import Atom
import Haskell
import Grammar hiding ( prec )
import qualified Grammar as G
import LR0 hiding ( fromList )
import Case
import qualified OrdUniqListSet as Set
import qualified SearchTree as ST
import Options
import Base
import Generate
import IO
import Monad
import Char
import List ( maximumBy )
import Prelude hiding ( lookup )
cmpLength :: RevList a -> RevList a -> Ordering
cmpLength x y = compare (revLength x) (revLength y)
generate :: [Flag] -> Grammar
-> [(Symbol, State)] -> GotoTable -> BranchTable -> IO [Decl]
generate opts grammar entries edges table
= do verb "* Generating Haskell code ... (--code=gvstack)"
when backtrFlag (warning "--backtrack is not supported")
when (k > 1) (warning "--lookahead=k with k > 1 is not supported")
when trFlag (warning "--trace is not supported")
return decls
where
verb = verbose opts
decls = [ Empty
, DataDecl nonterminal_tcon
[ (unCon (ntName n), typesOf n) | n <- nonterminals grammar ]
, Empty
, TypeDecl parser_tcon ([if lexFlag then terminal_tcon else List [terminal_tcon]]
<->> (result_tcon <$> [nonterminal_tcon]))
, Empty
, TypeDecl (vstack_tcon <$> [vs_var, v_var])
(Tuple [Tuple [vs_var, [nonterminal_tcon] <->> parser_tcon], v_var])
, Empty ]
++ [ funbind (globalNTName n <$> [tr_var | not lexFlag])
(next_n s [Tuple []] <>>=>
Fun [ntName n <$> (genVars n)]
(hsReturn <$> [Tuple (genVars n)]))
| (n, s) <- entries ]
++ concat [ Empty
-- : AComment [" state " ++ show (snumber s) ++ reportConflicts cases ++ " "]
: genState_n s cases
| (s, cases) <- ST.toList table ]
++ concat [ [ Empty ]
++ [ AComment ["# NOINLINE " ++ string (unVar red) ++ " #"] | noinline ]
++ [ let cont = if isStart (rlhs r) then accept_var else g_var in
funbind (red <$> [genStack (revList (rrhs r)), x_var])
(evaluate (argsOf (rlhs r))
(\ args -> cont <$> [ntName (rlhs r) <$> args, x_var])) ]
| r <- productions grammar, let red = reduce_var (rnumber r) ]
++ [ Empty
, funbind (state_var <$> [action_var, goto_var, vs_var, x_var])
(local [ funbind gs_var (Tuple [vs_var, g_var])
, funbind (g_var <$> [v_var]) (goto_var <$> [v_var, gs_var])]
(action_var <$> [if lexFlag then t_var
else hsHead <$> [ts_var], gs_var, x_var]))
, Empty
, funbind (shift_var <$> [state_var, v_var, vs_var, x_var])
(if lexFlag then
hsGet <>>=> (state_var <$> [Tuple [vs_var, v_var]])
else
state_var <$> [Tuple [vs_var, v_var], hsTail <$> [ts_var]])
, Empty
, funbind (shift'_var <$> [state_var, v_var, vs_var, x_var])
(if lexFlag then
state_var <$> [Tuple [vs_var, v_var], t_var]
else
state_var <$> [Tuple [vs_var, v_var], ts_var])
, Empty
, funbind (accept_var <$> [v_var, anon]) (hsReturn <$> [v_var])
, Empty
, funbind (goto_var <$> [state_var, v_var, vs_var])
(state_var <$> [Tuple [vs_var, v_var]])
, Empty
, funbind (error_var <$> ([ la_var | expFlag ] ++ [gs_var, x_var]))
(hsFrown <$> ([ la_var | expFlag ] ++ [x_var]))
, Empty
, funbind (notpossible x_var) (
hsFail <$> [stringLiteral "\"The `impossible' happened.\""])]
k = lookahead opts
trFlag = Trace `elem` opts
lexFlag = Lexer `elem` opts
expFlag = Expected `elem` opts
backtrFlag = Backtrack `elem` opts
noinline = Noinline `elem` opts
genState_n s cases
= [ Sig [unVar (state_n s)]
([stack_type (maximumBy cmpLength [ istack i | i <- Set.toList q ])] <->> parser_tcon)
, funbind (state_n s)
(state_var <$> [action_n s, if null gotos then hsUndefined else goto_n s])
, Empty
, funbind (action_n s <$> [t_var]) (genBody cases) ]
++ [ Empty | not (null gotos)]
++ gotos
++ [Empty]
where
q :\/ _q' = items s
gotos = [ funbind (goto_n s <$> [ntName v <$> genVars v])
(goto_var <$> [state_n s2, Tuple (genVars v)])
| (s1, v, s2) <- edges, s1 == s, nonterminal v ]
genBody (ReduceN rs)
| equal (map pnumber rs)
= reduce_n (head rs)
| otherwise = error "not LALR" -- TODO: Is this correct? One could use additional lookahead.
genBody (TokenCase es bs la)
= switch t_var ([ (fresh t, genExpr e (genVars t))
| (t, e) <- es ]
++ [(anon, if null bs then
frown la
else
genExpr (head bs) [])])
genBody _ = impossible "GVStack.genBody"
genExpr (Shift1 (_, t, s')) vs
= shift <$> [state_n s', Tuple vs]
where shift = if modifier t == Insert then shift'_var else shift_var
genExpr (ReduceN rs) _vs
| equal (map pnumber rs)
= reduce_n (head rs)
| otherwise = error "not LALR"
genExpr (ShiftReduce e _b) vs
= genExpr (Shift1 e) vs -- select shift (for the moment)
genExpr (ReduceReduce rs) vs
= genExpr (ReduceN [head rs]) vs
genExpr _ _ = impossible "GVStack.genExpr"
genStack Nil = Tuple [anon, g_var]
genStack (st :> v) = Tuple [Tuple [genStack st, Tuple (argsOf v)], anon]
stack_type Nil = vs_var
stack_type (st :> v) = vstack_tcon <$> [stack_type st, Tuple (typesOf v)]
next_n s ks
| lexFlag = hsGet <>>=> state_n' s ks
| otherwise = state_n' s ks <$> [tr_var]
where state_n' i ks' = state_n i <$> ks' -- HACK to fit the type
-- catchall' la rhss = if null rhss then frown la else foldr1 (<|>) rhss
frown la
| expFlag = error_var <$> [expected la]
| otherwise = error_var
x_var = if lexFlag then t_var else ts_var
{-
FunBind lhs rhs <||> alt = FunBind lhs (rhs <|> alt)
e1 <|> e2
| backtrFlag = Infix e1 "`mplus`" e2
| otherwise = e1
-}
state_n i = wrap_var ("state_" ++ smangle i)
action_n i = wrap_var ("action_" ++ smangle i)
goto_n i = wrap_var ("goto_" ++ smangle i)
reduce_n a = wrap_var ("reduce_" ++ pmangle a)
notpossible ts = impossible_var <$> [ts]
state_var = wrap_var "state"
shift_var = wrap_var "shift"
shift'_var = wrap_var "shift'"
action_var = wrap_var "action"
goto_var = wrap_var "goto"
accept_var = wrap_var "accept"
error_var = wrap_var "error"
reduce_var i = wrap_var ("reduce_" ++ show i)
impossible_var = wrap_var "impossible"
ts_var = wrap_var "ts"
tr_var = wrap_var "tr"
t_var = wrap_var "t"
g_var = wrap_var "g"
gs_var = wrap_var "gs"
v_var = wrap_var "v"
vs_var = wrap_var "vs"
la_var = wrap_var "la"
parser_tcon = wrap_con "Parser"
vstack_tcon = wrap_con "VStack"
nonterminal_tcon = wrap_con "Nonterminal"
globalNTName v = var (string (name v))
ntName v = wrap_con (rename (name v))
rename i
| isPrimed i = string i ++ "'" -- NB. A prime for the new start symbols.
| otherwise = string i
wrap s = prefix opts ++ s ++ suffix opts
wrap_var s = var (wrap s)
wrap_con s = con (wrap s)
|
