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271
src/GF/Formalism/Utilities.hs
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271
src/GF/Formalism/Utilities.hs
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----------------------------------------------------------------------
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-- |
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-- Maintainer : PL
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-- Stability : (stable)
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-- Portability : (portable)
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--
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-- > CVS $Date: 2005/04/11 13:52:50 $
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-- > CVS $Author: peb $
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-- > CVS $Revision: 1.1 $
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--
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-- Basic type declarations and functions for grammar formalisms
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-----------------------------------------------------------------------------
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module GF.Formalism.Utilities where
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import Monad
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import Array
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import List (groupBy)
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import GF.Data.SortedList
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import GF.Data.Assoc
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import GF.Data.Utilities (sameLength, foldMerge, splitBy)
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import GF.Infra.Print
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------------------------------------------------------------
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-- * symbols
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data Symbol c t = Cat c | Tok t
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deriving (Eq, Ord, Show)
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symbol :: (c -> a) -> (t -> a) -> Symbol c t -> a
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symbol fc ft (Cat cat) = fc cat
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symbol fc ft (Tok tok) = ft tok
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mapSymbol :: (c -> d) -> (t -> u) -> Symbol c t -> Symbol d u
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mapSymbol fc ft = symbol (Cat . fc) (Tok . ft)
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filterCats :: [Symbol c t] -> [c]
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filterCats syms = [ cat | Cat cat <- syms ]
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filterToks :: [Symbol c t] -> [t]
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filterToks syms = [ tok | Tok tok <- syms ]
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------------------------------------------------------------
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-- * edges
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data Edge s = Edge Int Int s
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deriving (Eq, Ord, Show)
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instance Functor Edge where
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fmap f (Edge i j s) = Edge i j (f s)
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------------------------------------------------------------
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-- * representaions of input tokens
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data Input t = MkInput { inputEdges :: [Edge t],
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inputBounds :: (Int, Int),
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inputFrom :: Array Int (Assoc t [Int]),
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inputTo :: Array Int (Assoc t [Int]),
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inputToken :: Assoc t [(Int, Int)]
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}
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makeInput :: Ord t => [Edge t] -> Input t
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input :: Ord t => [t] -> Input t
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inputMany :: Ord t => [[t]] -> Input t
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instance Show t => Show (Input t) where
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show input = "makeInput " ++ show (inputEdges input)
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----------
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makeInput inEdges | null inEdges = input []
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| otherwise = MkInput inEdges inBounds inFrom inTo inToken
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where inBounds = foldr1 minmax [ (i, j) | Edge i j _ <- inEdges ]
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where minmax (a, b) (a', b') = (min a a', max b b')
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inFrom = fmap (accumAssoc id) $ accumArray (<++>) [] inBounds $
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[ (i, [(tok, j)]) | Edge i j tok <- inEdges ]
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inTo = fmap (accumAssoc id) $ accumArray (<++>) [] inBounds
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[ (j, [(tok, i)]) | Edge i j tok <- inEdges ]
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inToken = accumAssoc id [ (tok, (i, j)) | Edge i j tok <- inEdges ]
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input toks = MkInput inEdges inBounds inFrom inTo inToken
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where inEdges = zipWith3 Edge [0..] [1..] toks
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inBounds = (0, length toks)
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inFrom = listArray inBounds $
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[ listAssoc [(tok, [j])] | (tok, j) <- zip toks [1..] ] ++ [ listAssoc [] ]
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inTo = listArray inBounds $
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[ listAssoc [] ] ++ [ listAssoc [(tok, [i])] | (tok, i) <- zip toks [0..] ]
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inToken = accumAssoc id [ (tok, (i, j)) | Edge i j tok <- inEdges ]
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inputMany toks = MkInput inEdges inBounds inFrom inTo inToken
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where inEdges = [ Edge i j t | (i, j, ts) <- zip3 [0..] [1..] toks, t <- ts ]
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inBounds = (0, length toks)
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inFrom = listArray inBounds $
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[ listAssoc [ (t, [j]) | t <- nubsort ts ] | (ts, j) <- zip toks [1..] ]
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++ [ listAssoc [] ]
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inTo = listArray inBounds $
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[ listAssoc [] ] ++
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[ listAssoc [ (t, [i]) | t <- nubsort ts ] | (ts, i) <- zip toks [0..] ]
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inToken = accumAssoc id [ (tok, (i, j)) | Edge i j tok <- inEdges ]
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------------------------------------------------------------
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-- * charts, forests & trees
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-- | The values of the chart, a list of key-daughters pairs,
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-- has unique keys. In essence, it is a map from 'n' to daughters.
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-- The daughters should be a set (not necessarily sorted) of rhs's.
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type SyntaxChart n e = Assoc e [(n, [[e]])]
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-- better(?) representation of forests:
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-- data Forest n = F (SMap n (SList [Forest n])) Bool
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-- ==
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-- type Forest n = GeneralTrie n (SList [Forest n]) Bool
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-- (the Bool == isMeta)
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data SyntaxForest n = FMeta
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| FNode n [[SyntaxForest n]]
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-- ^ The outer list should be a set (not necessarily sorted)
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-- of possible alternatives. Ie. the outer list
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-- is a disjunctive node, and the inner lists
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-- are (conjunctive) concatenative nodes
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deriving (Eq, Ord, Show)
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data SyntaxTree n = TMeta | TNode n [SyntaxTree n]
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deriving (Eq, Ord, Show)
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forestName :: SyntaxForest n -> Maybe n
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forestName (FNode n _) = Just n
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forestName (FMeta) = Nothing
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treeName :: SyntaxTree n -> Maybe n
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treeName (TNode n _) = Just n
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treeName (TMeta) = Nothing
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instance Functor SyntaxTree where
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fmap f (TNode n trees) = TNode (f n) $ map (fmap f) trees
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fmap f (TMeta) = TMeta
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instance Functor SyntaxForest where
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fmap f (FNode n forests) = FNode (f n) $ map (map (fmap f)) forests
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fmap f (FMeta) = FMeta
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{- måste tänka mer på detta:
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compactForests :: Ord n => [SyntaxForest n] -> SList (SyntaxForest n)
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compactForests = map joinForests . groupBy eqNames . sortForests
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where eqNames f g = forestName f == forestName g
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sortForests = foldMerge mergeForests [] . map return
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mergeForests [] gs = gs
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mergeForests fs [] = fs
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mergeForests fs@(f:fs') gs@(g:gs')
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= case forestName f `compare` forestName g of
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LT -> f : mergeForests fs' gs
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GT -> g : mergeForests fs gs'
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EQ -> f : g : mergeForests fs' gs'
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joinForests fs = case forestName (head fs) of
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Nothing -> FMeta
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Just name -> FNode name $
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compactDaughters $
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concat [ fss | FNode _ fss <- fs ]
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compactDaughters fss = case head fss of
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[] -> [[]]
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[_] -> map return $ compactForests $ concat fss
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_ -> nubsort fss
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-}
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-- ** conversions between representations
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forest2trees :: SyntaxForest n -> SList (SyntaxTree n)
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forest2trees (FNode n forests) = map (TNode n) $ forests >>= mapM forest2trees
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forest2trees (FMeta) = [TMeta]
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chart2forests :: (Ord n, Ord e) =>
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SyntaxChart n e -- ^ The complete chart
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-> (e -> Bool) -- ^ When is an edge 'FMeta'?
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-> [e] -- ^ The starting edges
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-> SList (SyntaxForest n) -- ^ The result has unique keys, ie. all 'n' are joined together.
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-- In essence, the result is a map from 'n' to forest daughters
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-- simplest implementation
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chart2forests chart isMeta = concatMap edge2forests
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where edge2forests edge = if isMeta edge then [FMeta]
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else map item2forest $ chart ? edge
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item2forest (name, children) = FNode name $ children >>= mapM edge2forests
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{-
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-- more intelligent(?) implementation,
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-- requiring that charts and forests are sorted maps and sorted sets
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chart2forests chart isMeta = es2fs
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where e2fs e = if isMeta e then [FMeta] else map i2f $ chart ? e
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es2fs es = if null metas then fs else FMeta : fs
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where (metas, nonMetas) = splitBy isMeta es
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fs = map i2f $ unionMap (<++>) $ map (chart ?) nonMetas
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i2f (name, children) = FNode name $
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case head children of
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[] -> [[]]
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[_] -> map return $ es2fs $ concat children
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_ -> children >>= mapM e2fs
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-}
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-- ** operations on forests
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unifyManyForests :: (Monad m, Eq n) => [SyntaxForest n] -> m (SyntaxForest n)
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unifyManyForests = foldM unifyForests FMeta
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-- | two forests can be unified, if either is 'FMeta', or both have the same parent,
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-- and all children can be unified
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unifyForests :: (Monad m, Eq n) => SyntaxForest n -> SyntaxForest n -> m (SyntaxForest n)
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unifyForests FMeta forest = return forest
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unifyForests forest FMeta = return forest
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unifyForests (FNode name1 children1) (FNode name2 children2)
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| name1 == name2 && not (null children) = return $ FNode name1 children
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| otherwise = fail "forest unification failure"
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where children = [ forests | forests1 <- children1, forests2 <- children2,
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sameLength forests1 forests2,
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forests <- zipWithM unifyForests forests1 forests2 ]
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-- ** operations on trees
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unifyManyTrees :: (Monad m, Eq n) => [SyntaxTree n] -> m (SyntaxTree n)
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unifyManyTrees = foldM unifyTrees TMeta
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-- | two trees can be unified, if either is 'TMeta',
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-- or both have the same parent, and their children can be unified
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unifyTrees :: (Monad m, Eq n) => SyntaxTree n -> SyntaxTree n -> m (SyntaxTree n)
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unifyTrees TMeta tree = return tree
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unifyTrees tree TMeta = return tree
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unifyTrees (TNode name1 children1) (TNode name2 children2)
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| name1 == name2 && sameLength children1 children2
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= liftM (TNode name1) $ zipWithM unifyTrees children1 children2
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| otherwise = fail "tree unification failure"
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------------------------------------------------------------
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-- pretty-printing
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instance (Print c, Print t) => Print (Symbol c t) where
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prt = symbol prt (simpleShow . prt)
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where simpleShow str = "\"" ++ concatMap mkEsc str ++ "\""
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mkEsc '\\' = "\\\\"
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mkEsc '\"' = "\\\""
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mkEsc '\n' = "\\n"
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mkEsc '\t' = "\\t"
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mkEsc chr = [chr]
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prtList = prtSep " "
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instance Print t => Print (Input t) where
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prt input = "input " ++ prt (inputEdges input)
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instance (Print s) => Print (Edge s) where
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prt (Edge i j s) = "[" ++ show i ++ "-" ++ show j ++ ": " ++ prt s ++ "]"
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prtList = prtSep ""
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instance (Print s) => Print (SyntaxTree s) where
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prt (TNode s trees) = prt s ++ "^{" ++ prtSep " " trees ++ "}"
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prt (TMeta) = "?"
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prtList = prtAfter "\n"
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instance (Print s) => Print (SyntaxForest s) where
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prt (FNode s forests) = prt s ++ "^{" ++ prtSep " | " (map (prtSep " ") forests) ++ "}"
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prt (FMeta) = "?"
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prtList = prtAfter "\n"
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