tock-mirror/fco2/ParseState.hs
2007-04-12 16:55:26 +00:00

89 lines
2.8 KiB
Haskell

-- | Compiler state.
module ParseState where
import Data.Generics
import Control.Monad.State
import qualified AST as A
import Metadata
-- FIXME This is a rather inappropriate name now...
-- | State necessary for compilation.
data ParseState = ParseState {
psLocalNames :: [(String, A.Name)],
psNames :: [(String, A.NameDef)],
psNameCounter :: Int,
psNonceCounter :: Int,
psPulledItems :: [A.Process -> A.Process]
}
deriving (Show, Data, Typeable)
instance Show (A.Process -> A.Process) where
show p = "(function on A.Process)"
emptyState :: ParseState
emptyState = ParseState {
psLocalNames = [],
psNames = [],
psNameCounter = 0,
psNonceCounter = 0,
psPulledItems = []
}
-- | Add the definition of a name.
psDefineName :: A.Name -> A.NameDef -> ParseState -> ParseState
psDefineName n nd ps = ps { psNames = (A.nameName n, nd) : psNames ps }
-- | Find the definition of a name.
psLookupName :: ParseState -> A.Name -> Maybe A.NameDef
psLookupName ps n = lookup (A.nameName n) (psNames ps)
-- | Generate a throwaway unique name.
makeNonce :: MonadState ParseState m => String -> m String
makeNonce s
= do ps <- get
let i = psNonceCounter ps
put ps { psNonceCounter = i + 1 }
return $ s ++ "_n" ++ show i
-- | Add a pulled item to the collection.
addPulled :: MonadState ParseState m => (A.Process -> A.Process) -> m ()
addPulled item
= do ps <- get
put $ ps { psPulledItems = item : psPulledItems ps }
-- | Apply pulled items to a Process.
applyPulled :: MonadState ParseState m => A.Process -> m A.Process
applyPulled ast
= do ps <- get
let ast' = foldl (\p f -> f p) ast (psPulledItems ps)
put $ ps { psPulledItems = [] }
return ast'
-- | Generate and define a nonce specification.
defineNonce :: MonadState ParseState m => Meta -> String -> A.SpecType -> A.NameType -> A.AbbrevMode -> m A.Specification
defineNonce m s st nt am
= do ns <- makeNonce s
let n = A.Name m A.ProcName ns
let nd = A.NameDef {
A.ndMeta = m,
A.ndName = ns,
A.ndOrigName = ns,
A.ndNameType = nt,
A.ndType = st,
A.ndAbbrevMode = am
}
modify $ psDefineName n nd
return (n, st)
-- | Generate and define a no-arg wrapper PROC around a process.
makeNonceProc :: MonadState ParseState m => Meta -> A.Process -> m A.Specification
makeNonceProc m p
= defineNonce m "wrapper_proc" (A.Proc m [] p) A.ProcName A.Abbrev
-- | Generate and define a VAL abbreviation.
makeNonceValIs :: MonadState ParseState m => Meta -> A.Type -> A.Expression -> m A.Specification
makeNonceValIs m t e
= defineNonce m "expr" (A.IsExpr m A.ValAbbrev t e) A.VariableName A.ValAbbrev