forked from GitHub/gf-core
39 lines
1.2 KiB
Haskell
39 lines
1.2 KiB
Haskell
module PennFormat(parseTreebank, showTree) where
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import Text.PrettyPrint
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import Data.Tree
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import Data.Char
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parseTreebank :: String -> [Tree String]
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parseTreebank [] = []
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parseTreebank (c:cs)
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| isSpace c = parseTreebank cs
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| c == '(' = let (ts,cs1) = parseTrees cs
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in ts ++ parseTreebank cs1
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parseTrees [] = ([],[])
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parseTrees (c:cs)
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| isSpace c = parseTrees cs
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| c == ')' = ([],cs)
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| c == '(' = let (w, cs1) = parseWord cs
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(children,cs2) = parseTrees cs1
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(rest, cs3) = parseTrees cs2
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in (Node (normalize w) children : rest,cs3)
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| otherwise = let (w, cs1) = parseWord (c:cs)
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(rest, cs2) = parseTrees cs1
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in (Node w [] : rest,cs2)
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normalize tag =
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let (tag0,mod) = break (=='-') tag
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in if null tag0
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then tag
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else tag0
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parseWord = break (\c -> isSpace c || c == '(' || c == ')')
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printTree (Node w []) = text w
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printTree (Node l children) = parens (text l <+> hsep (map printTree children))
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showTree :: Tree String -> String
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showTree = render . printTree
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