Files
gf-core/src/GF/Data/Operations.hs

375 lines
10 KiB
Haskell

----------------------------------------------------------------------
-- |
-- Module : Operations
-- Maintainer : AR
-- Stability : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/11/11 16:12:41 $
-- > CVS $Author: bringert $
-- > CVS $Revision: 1.22 $
--
-- some auxiliary GF operations. AR 19\/6\/1998 -- 6\/2\/2001
--
-- Copyright (c) Aarne Ranta 1998-2000, under GNU General Public License (see GPL)
-----------------------------------------------------------------------------
module GF.Data.Operations (-- * misc functions
ifNull, onSnd,
-- * the Error monad
Err(..), err, maybeErr, testErr, errVal, errIn,
lookupErr,
mapPairListM, mapPairsM, pairM,
singleton, mapsErr, mapsErrTree,
-- ** checking
checkUnique,
-- * binary search trees; now with FiniteMap
BinTree, emptyBinTree, isInBinTree, justLookupTree,
lookupTree, lookupTreeMany, lookupTreeManyAll, updateTree,
buildTree, filterBinTree,
sorted2tree, mapTree, mapMTree, tree2list,
-- * printing
indent, (+++), (++-), (++++), (+++++),
prUpper, prReplicate, prTList, prQuotedString, prParenth, prCurly,
prBracket, prArgList, prSemicList, prCurlyList, restoreEscapes,
numberedParagraphs, prConjList, prIfEmpty, wrapLines,
-- * extra
combinations,
-- * topological sorting with test of cyclicity
topoTest,
-- * the generic fix point iterator
iterFix,
-- * chop into separator-separated parts
chunks, readIntArg,
-- * state monad with error; from Agda 6\/11\/2001
STM(..), appSTM, stm, stmr, readSTM, updateSTM, writeSTM, done,
-- * error monad class
ErrorMonad(..), checkAgain, checks, allChecks, doUntil
) where
import Data.Char (isSpace, toUpper, isSpace, isDigit)
import Data.List (nub, sortBy, sort, deleteBy, nubBy)
import qualified Data.Map as Map
import Data.Map (Map)
import Control.Monad (liftM,liftM2, MonadPlus, mzero, mplus)
import GF.Data.ErrM
import GF.Data.Relation
infixr 5 +++
infixr 5 ++-
infixr 5 ++++
infixr 5 +++++
ifNull :: b -> ([a] -> b) -> [a] -> b
ifNull b f xs = if null xs then b else f xs
onSnd :: (a -> b) -> (c,a) -> (c,b)
onSnd f (x, y) = (x, f y)
-- the Error monad
-- | analogue of @maybe@
err :: (String -> b) -> (a -> b) -> Err a -> b
err d f e = case e of
Ok a -> f a
Bad s -> d s
-- | add msg s to @Maybe@ failures
maybeErr :: String -> Maybe a -> Err a
maybeErr s = maybe (Bad s) Ok
testErr :: Bool -> String -> Err ()
testErr cond msg = if cond then return () else Bad msg
errVal :: a -> Err a -> a
errVal a = err (const a) id
errIn :: String -> Err a -> Err a
errIn msg = err (\s -> Bad (s ++++ "OCCURRED IN" ++++ msg)) return
lookupErr :: (Eq a,Show a) => a -> [(a,b)] -> Err b
lookupErr a abs = maybeErr ("Unknown" +++ show a) (lookup a abs)
mapPairListM :: Monad m => ((a,b) -> m c) -> [(a,b)] -> m [(a,c)]
mapPairListM f xys = mapM (\ p@(x,_) -> liftM ((,) x) (f p)) xys
mapPairsM :: Monad m => (b -> m c) -> [(a,b)] -> m [(a,c)]
mapPairsM f xys = mapM (\ (x,y) -> liftM ((,) x) (f y)) xys
pairM :: Monad a => (b -> a c) -> (b,b) -> a (c,c)
pairM op (t1,t2) = liftM2 (,) (op t1) (op t2)
singleton :: a -> [a]
singleton = (:[])
-- checking
checkUnique :: (Show a, Eq a) => [a] -> [String]
checkUnique ss = ["overloaded" +++ show s | s <- nub overloads] where
overloads = filter overloaded ss
overloaded s = length (filter (==s) ss) > 1
-- binary search trees
type BinTree a b = Map a b
emptyBinTree :: BinTree a b
emptyBinTree = Map.empty
isInBinTree :: (Ord a) => a -> BinTree a b -> Bool
isInBinTree = Map.member
justLookupTree :: (Monad m,Ord a) => a -> BinTree a b -> m b
justLookupTree = lookupTree (const [])
lookupTree :: (Monad m,Ord a) => (a -> String) -> a -> BinTree a b -> m b
lookupTree pr x tree = case Map.lookup x tree of
Just y -> return y
_ -> fail ("no occurrence of element" +++ pr x)
lookupTreeMany :: Ord a => (a -> String) -> [BinTree a b] -> a -> Err b
lookupTreeMany pr (t:ts) x = case lookupTree pr x t of
Ok v -> return v
_ -> lookupTreeMany pr ts x
lookupTreeMany pr [] x = Bad $ "failed to find" +++ pr x
lookupTreeManyAll :: Ord a => (a -> String) -> [BinTree a b] -> a -> [b]
lookupTreeManyAll pr (t:ts) x = case lookupTree pr x t of
Ok v -> v : lookupTreeManyAll pr ts x
_ -> lookupTreeManyAll pr ts x
lookupTreeManyAll pr [] x = []
updateTree :: (Ord a) => (a,b) -> BinTree a b -> BinTree a b
updateTree (a,b) = Map.insert a b
buildTree :: (Ord a) => [(a,b)] -> BinTree a b
buildTree = Map.fromList
sorted2tree :: Ord a => [(a,b)] -> BinTree a b
sorted2tree = Map.fromAscList
mapTree :: ((a,b) -> c) -> BinTree a b -> BinTree a c
mapTree f = Map.mapWithKey (\k v -> f (k,v))
mapMTree :: (Ord a,Monad m) => ((a,b) -> m c) -> BinTree a b -> m (BinTree a c)
mapMTree f t = liftM Map.fromList $ sequence [liftM ((,) k) (f (k,x)) | (k,x) <- Map.toList t]
filterBinTree :: Ord a => (a -> b -> Bool) -> BinTree a b -> BinTree a b
filterBinTree = Map.filterWithKey
tree2list :: BinTree a b -> [(a,b)] -- inorder
tree2list = Map.toList
-- printing
indent :: Int -> String -> String
indent i s = replicate i ' ' ++ s
(+++), (++-), (++++), (+++++) :: String -> String -> String
a +++ b = a ++ " " ++ b
a ++- "" = a
a ++- b = a +++ b
a ++++ b = a ++ "\n" ++ b
a +++++ b = a ++ "\n\n" ++ b
prUpper :: String -> String
prUpper s = s1 ++ s2' where
(s1,s2) = span isSpace s
s2' = case s2 of
c:t -> toUpper c : t
_ -> s2
prReplicate :: Int -> String -> String
prReplicate n s = concat (replicate n s)
prTList :: String -> [String] -> String
prTList t ss = case ss of
[] -> ""
[s] -> s
s:ss -> s ++ t ++ prTList t ss
prQuotedString :: String -> String
prQuotedString x = "\"" ++ restoreEscapes x ++ "\""
prParenth :: String -> String
prParenth s = if s == "" then "" else "(" ++ s ++ ")"
prCurly, prBracket :: String -> String
prCurly s = "{" ++ s ++ "}"
prBracket s = "[" ++ s ++ "]"
prArgList, prSemicList, prCurlyList :: [String] -> String
prArgList = prParenth . prTList ","
prSemicList = prTList " ; "
prCurlyList = prCurly . prSemicList
restoreEscapes :: String -> String
restoreEscapes s =
case s of
[] -> []
'"' : t -> '\\' : '"' : restoreEscapes t
'\\': t -> '\\' : '\\' : restoreEscapes t
c : t -> c : restoreEscapes t
numberedParagraphs :: [[String]] -> [String]
numberedParagraphs t = case t of
[] -> []
p:[] -> p
_ -> concat [(show n ++ ".") : s | (n,s) <- zip [1..] t]
prConjList :: String -> [String] -> String
prConjList c [] = ""
prConjList c [s] = s
prConjList c [s,t] = s +++ c +++ t
prConjList c (s:tt) = s ++ "," +++ prConjList c tt
prIfEmpty :: String -> String -> String -> String -> String
prIfEmpty em _ _ [] = em
prIfEmpty em nem1 nem2 s = nem1 ++ s ++ nem2
-- | Thomas Hallgren's wrap lines
wrapLines :: Int -> String -> String
wrapLines n "" = ""
wrapLines n s@(c:cs) =
if isSpace c
then c:wrapLines (n+1) cs
else case lex s of
[(w,rest)] -> if n'>=76
then '\n':w++wrapLines l rest
else w++wrapLines n' rest
where n' = n+l
l = length w
_ -> s -- give up!!
--- optWrapLines = if argFlag "wraplines" True then wrapLines 0 else id
-- | 'combinations' is the same as @sequence@!!!
-- peb 30\/5-04
combinations :: [[a]] -> [[a]]
combinations t = case t of
[] -> [[]]
aa:uu -> [a:u | a <- aa, u <- combinations uu]
-- | topological sorting with test of cyclicity
topoTest :: Ord a => [(a,[a])] -> Either [a] [[a]]
topoTest = topologicalSort . mkRel'
-- | the generic fix point iterator
iterFix :: Eq a => ([a] -> [a]) -> [a] -> [a]
iterFix more start = iter start start
where
iter old new = if (null new')
then old
else iter (new' ++ old) new'
where
new' = filter (`notElem` old) (more new)
-- | chop into separator-separated parts
chunks :: Eq a => a -> [a] -> [[a]]
chunks sep ws = case span (/= sep) ws of
(a,_:b) -> a : bs where bs = chunks sep b
(a, []) -> if null a then [] else [a]
readIntArg :: String -> Int
readIntArg n = if (not (null n) && all isDigit n) then read n else 0
-- state monad with error; from Agda 6/11/2001
newtype STM s a = STM (s -> Err (a,s))
appSTM :: STM s a -> s -> Err (a,s)
appSTM (STM f) s = f s
stm :: (s -> Err (a,s)) -> STM s a
stm = STM
stmr :: (s -> (a,s)) -> STM s a
stmr f = stm (\s -> return (f s))
instance Monad (STM s) where
return a = STM (\s -> return (a,s))
STM c >>= f = STM (\s -> do
(x,s') <- c s
let STM f' = f x
f' s')
readSTM :: STM s s
readSTM = stmr (\s -> (s,s))
updateSTM :: (s -> s) -> STM s ()
updateSTM f = stmr (\s -> ((),f s))
writeSTM :: s -> STM s ()
writeSTM s = stmr (const ((),s))
done :: Monad m => m ()
done = return ()
class Monad m => ErrorMonad m where
raise :: String -> m a
handle :: m a -> (String -> m a) -> m a
handle_ :: m a -> m a -> m a
handle_ a b = a `handle` (\_ -> b)
instance ErrorMonad Err where
raise = Bad
handle a@(Ok _) _ = a
handle (Bad i) f = f i
instance ErrorMonad (STM s) where
raise msg = STM (\s -> raise msg)
handle (STM f) g = STM (\s -> (f s)
`handle` (\e -> let STM g' = (g e) in
g' s))
-- error recovery with multiple reporting AR 30/5/2008
mapsErr :: (a -> Err b) -> [a] -> Err [b]
mapsErr f = seqs . map f where
seqs es = case es of
Ok v : ms -> case seqs ms of
Ok vs -> return (v : vs)
b -> b
Bad s : ms -> case seqs ms of
Ok vs -> Bad s
Bad ss -> Bad (s +++++ ss)
[] -> return []
mapsErrTree :: (Ord a) => ((a,b) -> Err (a,c)) -> BinTree a b -> Err (BinTree a c)
mapsErrTree f t = mapsErr f (tree2list t) >>= return . sorted2tree
-- | if the first check fails try another one
checkAgain :: ErrorMonad m => m a -> m a -> m a
checkAgain c1 c2 = handle_ c1 c2
checks :: ErrorMonad m => [m a] -> m a
checks [] = raise "no chance to pass"
checks cs = foldr1 checkAgain cs
allChecks :: ErrorMonad m => [m a] -> m [a]
allChecks ms = case ms of
(m: ms) -> let rs = allChecks ms in handle_ (liftM2 (:) m rs) rs
_ -> return []
doUntil :: ErrorMonad m => (a -> Bool) -> [m a] -> m a
doUntil cond ms = case ms of
a:as -> do
v <- a
if cond v then return v else doUntil cond as
_ -> raise "no result"