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gf-core/src/GF/UseGrammar/Session.hs
aarne 1142d18a08 -s
2004-08-13 20:46:54 +00:00

138 lines
4.2 KiB
Haskell

module Session where
import Abstract
import Option
import Custom
import Editing
import ShellState ---- grammar
import Operations
-- First version 8/2001. Adapted to GFC with modules 19/6/2003.
-- Nothing had to be changed, which is a sign of good modularity.
-- keep these abstract
type SState = [(State,([Exp],[Clip]),SInfo)] -- exps: candidate refinements,clipboard
type SInfo = ([String],(Int,Options)) -- string is message, int is the view
initSState :: SState
initSState = [(initState, ([],[]), (["Select 'New' category to start"],(0,noOptions)))]
-- instead of empty
type Clip = Tree ---- (Exp,Type)
okInfo n = ([],(n,True))
stateSState ((s,_,_):_) = s
candsSState ((_,(ts,_),_):_)= ts
clipSState ((_,(_,ts),_):_)= ts
infoSState ((_,_,i):_) = i
msgSState ((_,_,(m,_)):_) = m
viewSState ((_,_,(_,(v,_))):_) = v
optsSState ((_,_,(_,(_,o))):_) = o
treeSState = actTree . stateSState
-- from state to state
type ECommand = SState -> SState
-- elementary commands
-- change state, drop cands, drop message, preserve options
changeState :: State -> ECommand
changeState s ss = changeMsg [] $ (s,([],clipSState ss),infoSState ss) : ss
changeCands :: [Exp] -> ECommand
changeCands ts ss@((s,(_,cb),(_,b)):_) = (s,(ts,cb),(candInfo ts,b)) : ss
addtoClip :: Clip -> ECommand
addtoClip t ss@((s,(ts,cb),(i,b)):_) = (s,(ts,t:cb),(i,b)) : ss
changeMsg :: [String] -> ECommand
changeMsg m ((s,ts,(_,b)):ss) = (s,ts,(m,b)) : ss -- just change message
changeView :: ECommand
changeView ((s,ts,(m,(v,b))):ss) = (s,ts,(m,(v+1,b))) : ss -- toggle view
withMsg :: [String] -> ECommand -> ECommand
withMsg m c = changeMsg m . c
changeStOptions :: (Options -> Options) -> ECommand
changeStOptions f ((s,ts,(m,(v,o))):ss) = (s,ts,(m,(v, f o))) : ss
noNeedForMsg = changeMsg [] -- everything's all right: no message
candInfo ts = case length ts of
0 -> ["no acceptable alternative"]
1 -> ["just one acceptable alternative"]
n -> [show n +++ "alternatives to select"]
-- keep SState abstract from this on
-- editing commands
action2command :: Action -> ECommand
action2command act state = case act (stateSState state) of
Ok s -> changeState s state
Bad m -> changeMsg [m] state
action2commandNext :: Action -> ECommand -- move to next meta after execution
action2commandNext act = action2command (\s -> act s >>= goNextMetaIfCan)
undoCommand :: ECommand
undoCommand ss@[_] = changeMsg ["cannot go back"] ss
undoCommand (_:ss) = changeMsg ["successful undo"] ss
selectCand :: CGrammar -> Int -> ECommand
selectCand gr i state = err (\m -> changeMsg [m] state) id $ do
exp <- candsSState state !? i
let s = stateSState state
tree <- annotateInState gr exp s
return $ case replaceSubTree tree s of
Ok st' -> changeState st' state
Bad s -> changeMsg [s] state
refineByExps :: Bool -> CGrammar -> [Exp] -> ECommand
refineByExps der gr trees = case trees of
[t] -> action2commandNext (refineWithExpTC der gr t)
_ -> changeCands trees
refineByTrees :: Bool -> CGrammar -> [Tree] -> ECommand
refineByTrees der gr trees = case trees of
[t] -> action2commandNext (refineOrReplaceWithTree der gr t)
_ -> changeCands $ map tree2exp trees
replaceByTrees :: CGrammar -> [Exp] -> ECommand
replaceByTrees gr trees = case trees of
[t] -> action2commandNext (\s ->
annotateExpInState gr t s >>= flip replaceSubTree s)
_ -> changeCands trees
replaceByEditCommand :: StateGrammar -> String -> ECommand
replaceByEditCommand gr co =
action2command $
maybe return ($ gr) $
lookupCustom customEditCommand (strCI co)
replaceByTermCommand :: Bool -> StateGrammar -> String -> Tree -> ECommand ----
replaceByTermCommand der gr co exp =
let g = grammar gr in
refineByTrees der g $ maybe [exp] (\f -> f gr exp) $
lookupCustom customTermCommand (strCI co)
possClipsSState :: StateGrammar -> SState -> [(Int,Clip)]
possClipsSState gr s = filter poss $ zip [0..] (clipSState s)
where
poss = possibleTreeVal cgr st . snd
st = stateSState s
cgr = grammar gr
getNumberedClip :: Int -> SState -> Err Clip
getNumberedClip i s = if length cs > i then return (cs !! i)
else Bad "not enough clips"
where
cs = clipSState s