87 lines
2.7 KiB
Haskell
87 lines
2.7 KiB
Haskell
-- from https://github.com/blaenk/blaenk.github.io
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{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE CPP #-}
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module TableOfContents (
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tableOfContents,
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ignoreTOC,
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collectHeaders,
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removeTOCMarker
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) where
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import Text.Pandoc
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import Text.Pandoc.Walk (walk, query)
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import Data.List (groupBy)
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import Data.Tree (Forest, Tree(Node))
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#if !(MIN_VERSION_base(4,11,0))
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import Data.Monoid ((<>), mconcat)
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#endif
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import Data.Function (on)
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import Data.Maybe (fromMaybe)
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import Text.Blaze.Html (preEscapedToHtml, (!))
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import Text.Blaze.Html.Renderer.String (renderHtml)
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import qualified Text.Blaze.Html5 as H
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import qualified Text.Blaze.Html5.Attributes as A
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headerLevel :: Block -> Int
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headerLevel (Header level _ _) = level
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headerLevel _ = error "not a header"
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ignoreTOC :: Block -> Block
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ignoreTOC (Header level (ident, classes, params) inline) =
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Header level (ident, "notoc" : classes, params) inline
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ignoreTOC x = x
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removeTOCMarker :: Block -> Block
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removeTOCMarker (BulletList (( (( Plain ((Str "toc"):_)):_)):_)) = Null
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removeTOCMarker x = x
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collectHeaders :: Block -> [Block]
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collectHeaders header@(Header _ (_, classes, _) _) =
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if "notoc" `elem` classes
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then []
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else [header]
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collectHeaders _ = []
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groupByHierarchy :: [Block] -> Forest Block
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groupByHierarchy = map (\(x:xs) -> Node x (groupByHierarchy xs)) . groupBy ((<) `on` headerLevel)
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markupHeader :: Tree Block -> H.Html
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markupHeader (Node (Header _ (ident, _, keyvals) inline) headers)
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| headers == [] = H.li $ link
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| otherwise = H.li $ link <> (H.ol $ markupHeaders headers)
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where render x = writeHtmlString def (Pandoc nullMeta [(Plain x)])
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section = fromMaybe (render inline) (lookup "toc" keyvals)
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link = H.a ! A.href (H.toValue $ "#" ++ ident) $ preEscapedToHtml section
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markupHeader _ = error "what"
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markupHeaders :: Forest Block -> H.Html
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markupHeaders = mconcat . map markupHeader
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createTable :: Forest Block -> H.Html
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createTable headers =
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(H.nav ! A.id "toc") $ do
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H.p "Contents"
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H.ol $ markupHeaders headers
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generateTOC :: [Block] -> String -> Block -> Block
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generateTOC [] _ x = x
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generateTOC headers alignment x@(BulletList (( (( Plain ((Str "toc"):_)):_)):_))
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| alignment == "right" = render . (! A.class_ "right-toc") . table $ headers
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| alignment == "left" = render . table $ headers
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| otherwise = x
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where render = (RawBlock "html") . renderHtml
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table = createTable . groupByHierarchy
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generateTOC _ _ x = x
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tableOfContents :: String -> Pandoc -> Pandoc
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tableOfContents alignment ast =
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if alignment /= "off"
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then let headers = query collectHeaders ast
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in walk (generateTOC headers alignment) ast
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else walk ignoreTOC ast
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