forked from GitHub/gf-core
c8cbd4477f
+ Eliminated vairous ad-hoc coersion functions between specific monads (IO, Err, IOE, Check) in favor of more general lifting functions (liftIO, liftErr). + Generalized many basic monadic operations from specific monads to arbitrary monads in the appropriate class (MonadIO and/or ErrorMonad), thereby completely eliminating the need for lifting functions in lots of places. This can be considered a small step forward towards a cleaner compiler API and more malleable compiler code in general.
393 lines
11 KiB
Haskell
393 lines
11 KiB
Haskell
----------------------------------------------------------------------
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-- |
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-- Module : Operations
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-- Maintainer : AR
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-- Stability : (stable)
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-- Portability : (portable)
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--
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-- > CVS $Date: 2005/11/11 16:12:41 $
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-- > CVS $Author: bringert $
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-- > CVS $Revision: 1.22 $
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--
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-- some auxiliary GF operations. AR 19\/6\/1998 -- 6\/2\/2001
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--
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-- Copyright (c) Aarne Ranta 1998-2000, under GNU General Public License (see GPL)
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-----------------------------------------------------------------------------
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module GF.Data.Operations (-- * misc functions
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ifNull,
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-- * the Error monad
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Err(..), err, maybeErr, testErr, errVal, errIn,
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lookupErr,
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mapPairListM, mapPairsM, pairM,
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singleton, --mapsErr, mapsErrTree,
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-- ** checking
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checkUnique,
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-- * binary search trees; now with FiniteMap
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BinTree, emptyBinTree, isInBinTree, justLookupTree,
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lookupTree, lookupTreeMany, lookupTreeManyAll, updateTree,
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buildTree, filterBinTree,
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sorted2tree, mapTree, mapMTree, tree2list,
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-- * printing
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indent, (+++), (++-), (++++), (+++++),
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prUpper, prReplicate, prTList, prQuotedString, prParenth, prCurly,
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prBracket, prArgList, prSemicList, prCurlyList, restoreEscapes,
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numberedParagraphs, prConjList, prIfEmpty, wrapLines,
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-- * extra
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combinations,
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-- * topological sorting with test of cyclicity
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topoTest, topoTest2,
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-- * the generic fix point iterator
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iterFix,
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-- * chop into separator-separated parts
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chunks, readIntArg,
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-- * state monad with error; from Agda 6\/11\/2001
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STM(..), appSTM, stm, stmr, readSTM, updateSTM, writeSTM, done,
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-- * error monad class
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ErrorMonad(..), checkAgain, checks, allChecks, doUntil,
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liftErr
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) where
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import Data.Char (isSpace, toUpper, isSpace, isDigit)
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import Data.List (nub, partition, (\\))
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import qualified Data.Map as Map
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import Data.Map (Map)
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import Control.Monad (liftM,liftM2)
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import GF.Data.ErrM
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import GF.Data.Relation
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infixr 5 +++
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infixr 5 ++-
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infixr 5 ++++
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infixr 5 +++++
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ifNull :: b -> ([a] -> b) -> [a] -> b
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ifNull b f xs = if null xs then b else f xs
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-- the Error monad
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-- | analogue of @maybe@
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err :: (String -> b) -> (a -> b) -> Err a -> b
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err d f e = case e of
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Ok a -> f a
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Bad s -> d s
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-- | add msg s to @Maybe@ failures
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maybeErr :: ErrorMonad m => String -> Maybe a -> m a
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maybeErr s = maybe (raise s) return
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testErr :: ErrorMonad m => Bool -> String -> m ()
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testErr cond msg = if cond then return () else raise msg
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errVal :: a -> Err a -> a
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errVal a = err (const a) id
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errIn :: ErrorMonad m => String -> m a -> m a
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errIn msg m = handle m (\s -> raise (s ++++ "OCCURRED IN" ++++ msg))
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lookupErr :: (ErrorMonad m,Eq a,Show a) => a -> [(a,b)] -> m b
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lookupErr a abs = maybeErr ("Unknown" +++ show a) (lookup a abs)
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mapPairListM :: Monad m => ((a,b) -> m c) -> [(a,b)] -> m [(a,c)]
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mapPairListM f xys = mapM (\ p@(x,_) -> liftM ((,) x) (f p)) xys
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mapPairsM :: Monad m => (b -> m c) -> [(a,b)] -> m [(a,c)]
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mapPairsM f xys = mapM (\ (x,y) -> liftM ((,) x) (f y)) xys
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pairM :: Monad a => (b -> a c) -> (b,b) -> a (c,c)
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pairM op (t1,t2) = liftM2 (,) (op t1) (op t2)
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singleton :: a -> [a]
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singleton = (:[])
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-- checking
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checkUnique :: (Show a, Eq a) => [a] -> [String]
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checkUnique ss = ["overloaded" +++ show s | s <- nub overloads] where
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overloads = filter overloaded ss
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overloaded s = length (filter (==s) ss) > 1
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-- binary search trees
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type BinTree a b = Map a b
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emptyBinTree :: BinTree a b
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emptyBinTree = Map.empty
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isInBinTree :: (Ord a) => a -> BinTree a b -> Bool
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isInBinTree = Map.member
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justLookupTree :: (Monad m,Ord a) => a -> BinTree a b -> m b
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justLookupTree = lookupTree (const [])
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lookupTree :: (Monad m,Ord a) => (a -> String) -> a -> BinTree a b -> m b
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lookupTree pr x tree = case Map.lookup x tree of
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Just y -> return y
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_ -> fail ("no occurrence of element" +++ pr x)
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lookupTreeMany :: Ord a => (a -> String) -> [BinTree a b] -> a -> Err b
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lookupTreeMany pr (t:ts) x = case lookupTree pr x t of
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Ok v -> return v
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_ -> lookupTreeMany pr ts x
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lookupTreeMany pr [] x = Bad $ "failed to find" +++ pr x
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lookupTreeManyAll :: Ord a => (a -> String) -> [BinTree a b] -> a -> [b]
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lookupTreeManyAll pr (t:ts) x = case lookupTree pr x t of
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Ok v -> v : lookupTreeManyAll pr ts x
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_ -> lookupTreeManyAll pr ts x
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lookupTreeManyAll pr [] x = []
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updateTree :: (Ord a) => (a,b) -> BinTree a b -> BinTree a b
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updateTree (a,b) = Map.insert a b
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buildTree :: (Ord a) => [(a,b)] -> BinTree a b
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buildTree = Map.fromList
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sorted2tree :: Ord a => [(a,b)] -> BinTree a b
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sorted2tree = Map.fromAscList
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mapTree :: ((a,b) -> c) -> BinTree a b -> BinTree a c
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mapTree f = Map.mapWithKey (\k v -> f (k,v))
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mapMTree :: (Ord a,Monad m) => ((a,b) -> m c) -> BinTree a b -> m (BinTree a c)
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mapMTree f t = liftM Map.fromList $ sequence [liftM ((,) k) (f (k,x)) | (k,x) <- Map.toList t]
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filterBinTree :: Ord a => (a -> b -> Bool) -> BinTree a b -> BinTree a b
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filterBinTree = Map.filterWithKey
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tree2list :: BinTree a b -> [(a,b)] -- inorder
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tree2list = Map.toList
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-- printing
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indent :: Int -> String -> String
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indent i s = replicate i ' ' ++ s
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(+++), (++-), (++++), (+++++) :: String -> String -> String
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a +++ b = a ++ " " ++ b
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a ++- "" = a
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a ++- b = a +++ b
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a ++++ b = a ++ "\n" ++ b
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a +++++ b = a ++ "\n\n" ++ b
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prUpper :: String -> String
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prUpper s = s1 ++ s2' where
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(s1,s2) = span isSpace s
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s2' = case s2 of
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c:t -> toUpper c : t
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_ -> s2
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prReplicate :: Int -> String -> String
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prReplicate n s = concat (replicate n s)
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prTList :: String -> [String] -> String
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prTList t ss = case ss of
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[] -> ""
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[s] -> s
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s:ss -> s ++ t ++ prTList t ss
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prQuotedString :: String -> String
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prQuotedString x = "\"" ++ restoreEscapes x ++ "\""
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prParenth :: String -> String
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prParenth s = if s == "" then "" else "(" ++ s ++ ")"
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prCurly, prBracket :: String -> String
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prCurly s = "{" ++ s ++ "}"
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prBracket s = "[" ++ s ++ "]"
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prArgList, prSemicList, prCurlyList :: [String] -> String
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prArgList = prParenth . prTList ","
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prSemicList = prTList " ; "
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prCurlyList = prCurly . prSemicList
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restoreEscapes :: String -> String
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restoreEscapes s =
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case s of
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[] -> []
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'"' : t -> '\\' : '"' : restoreEscapes t
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'\\': t -> '\\' : '\\' : restoreEscapes t
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c : t -> c : restoreEscapes t
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numberedParagraphs :: [[String]] -> [String]
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numberedParagraphs t = case t of
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[] -> []
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p:[] -> p
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_ -> concat [(show n ++ ".") : s | (n,s) <- zip [1..] t]
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prConjList :: String -> [String] -> String
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prConjList c [] = ""
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prConjList c [s] = s
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prConjList c [s,t] = s +++ c +++ t
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prConjList c (s:tt) = s ++ "," +++ prConjList c tt
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prIfEmpty :: String -> String -> String -> String -> String
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prIfEmpty em _ _ [] = em
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prIfEmpty em nem1 nem2 s = nem1 ++ s ++ nem2
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-- | Thomas Hallgren's wrap lines
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wrapLines :: Int -> String -> String
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wrapLines n "" = ""
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wrapLines n s@(c:cs) =
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if isSpace c
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then c:wrapLines (n+1) cs
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else case lex s of
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[(w,rest)] -> if n'>=76
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then '\n':w++wrapLines l rest
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else w++wrapLines n' rest
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where n' = n+l
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l = length w
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_ -> s -- give up!!
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--- optWrapLines = if argFlag "wraplines" True then wrapLines 0 else id
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-- | 'combinations' is the same as @sequence@!!!
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-- peb 30\/5-04
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combinations :: [[a]] -> [[a]]
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combinations t = case t of
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[] -> [[]]
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aa:uu -> [a:u | a <- aa, u <- combinations uu]
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-- | topological sorting with test of cyclicity
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topoTest :: Ord a => [(a,[a])] -> Either [a] [[a]]
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topoTest = topologicalSort . mkRel'
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-- | topological sorting with test of cyclicity, new version /TH 2012-06-26
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topoTest2 :: Ord a => [(a,[a])] -> Either [[a]] [[a]]
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topoTest2 g0 = maybe (Right cycles) Left (tsort g)
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where
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g = g0++[(n,[])|n<-nub (concatMap snd g0)\\map fst g0]
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cycles = findCycles (mkRel' g)
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tsort nes =
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case partition (null.snd) nes of
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([],[]) -> Just []
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([],_) -> Nothing
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(ns,rest) -> (leaves:) `fmap` tsort [(n,es \\ leaves) | (n,es)<-rest]
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where leaves = map fst ns
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-- | the generic fix point iterator
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iterFix :: Eq a => ([a] -> [a]) -> [a] -> [a]
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iterFix more start = iter start start
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where
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iter old new = if (null new')
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then old
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else iter (new' ++ old) new'
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where
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new' = filter (`notElem` old) (more new)
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-- | chop into separator-separated parts
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chunks :: Eq a => a -> [a] -> [[a]]
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chunks sep ws = case span (/= sep) ws of
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(a,_:b) -> a : bs where bs = chunks sep b
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(a, []) -> if null a then [] else [a]
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readIntArg :: String -> Int
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readIntArg n = if (not (null n) && all isDigit n) then read n else 0
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-- state monad with error; from Agda 6/11/2001
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newtype STM s a = STM (s -> Err (a,s))
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appSTM :: STM s a -> s -> Err (a,s)
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appSTM (STM f) s = f s
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stm :: (s -> Err (a,s)) -> STM s a
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stm = STM
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stmr :: (s -> (a,s)) -> STM s a
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stmr f = stm (\s -> return (f s))
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instance Functor (STM s) where fmap = liftM
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instance Monad (STM s) where
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return a = STM (\s -> return (a,s))
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STM c >>= f = STM (\s -> do
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(x,s') <- c s
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let STM f' = f x
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f' s')
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readSTM :: STM s s
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readSTM = stmr (\s -> (s,s))
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updateSTM :: (s -> s) -> STM s ()
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updateSTM f = stmr (\s -> ((),f s))
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writeSTM :: s -> STM s ()
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writeSTM s = stmr (const ((),s))
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done :: Monad m => m ()
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done = return ()
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class (Functor m,Monad m) => ErrorMonad m where
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raise :: String -> m a
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handle :: m a -> (String -> m a) -> m a
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handle_ :: m a -> m a -> m a
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handle_ a b = a `handle` (\_ -> b)
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instance ErrorMonad Err where
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raise = Bad
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handle a@(Ok _) _ = a
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handle (Bad i) f = f i
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liftErr e = err raise return e
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instance ErrorMonad (STM s) where
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raise msg = STM (\s -> raise msg)
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handle (STM f) g = STM (\s -> (f s)
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`handle` (\e -> let STM g' = (g e) in
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g' s))
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{-
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-- error recovery with multiple reporting AR 30/5/2008
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mapsErr :: (a -> Err b) -> [a] -> Err [b]
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mapsErr f = seqs . map f where
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seqs es = case es of
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Ok v : ms -> case seqs ms of
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Ok vs -> return (v : vs)
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b -> b
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Bad s : ms -> case seqs ms of
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Ok vs -> Bad s
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Bad ss -> Bad (s +++++ ss)
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[] -> return []
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mapsErrTree :: (Ord a) => ((a,b) -> Err (a,c)) -> BinTree a b -> Err (BinTree a c)
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mapsErrTree f t = mapsErr f (tree2list t) >>= return . sorted2tree
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-}
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-- | if the first check fails try another one
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checkAgain :: ErrorMonad m => m a -> m a -> m a
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checkAgain c1 c2 = handle_ c1 c2
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checks :: ErrorMonad m => [m a] -> m a
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checks [] = raise "no chance to pass"
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checks cs = foldr1 checkAgain cs
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allChecks :: ErrorMonad m => [m a] -> m [a]
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allChecks ms = case ms of
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(m: ms) -> let rs = allChecks ms in handle_ (liftM2 (:) m rs) rs
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_ -> return []
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doUntil :: ErrorMonad m => (a -> Bool) -> [m a] -> m a
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doUntil cond ms = case ms of
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a:as -> do
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v <- a
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if cond v then return v else doUntil cond as
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_ -> raise "no result"
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