72 lines
2.2 KiB
Haskell
72 lines
2.2 KiB
Haskell
{-# LANGUAGE LambdaCase #-}
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{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE MultiWayIf #-}
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{-# LANGUAGE ScopedTypeVariables #-}
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import qualified Text.HTML.TagSoup as Tag
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import qualified Data.Text as Text
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import Data.Text (Text)
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import qualified Data.List as List
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import Data.Maybe
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import Text.Nicify
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import qualified Text.Read as Read
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import Numeric.Natural
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import Data.Either
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import qualified Data.ByteString as ByteString
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import qualified Data.Text.Encoding
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parseNat :: Text.Text -> Maybe Natural
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parseNat = Read.readMaybe . Text.unpack
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printNice :: Show a => a -> IO ()
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printNice = putStrLn . nicify . show
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type Tag = Tag.Tag Text.Text
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main = do
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reverseHtml <- readStdinUtf8
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printNice $ List.sortOn snd $ packagesAndReverseDeps reverseHtml
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where
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readStdinUtf8 = Data.Text.Encoding.decodeUtf8 <$> ByteString.getContents
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-- | reads the table provided by https://packdeps.haskellers.com/reverse
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-- figuring out all sections (starting with the link to the package name),
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-- then figuring out the name of the package and the first column,
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-- which is the number of reverse dependencies of the package
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packagesAndReverseDeps reverseHtml = do
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let tags = Tag.parseTags reverseHtml
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let sections = Tag.partitions (isJust . reverseLink) tags
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let sectionNames = map (fromJust . reverseLink . head) sections
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mapMaybe
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(\(name :: Text.Text, sect) -> do
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reverseDeps <- firstNaturalNumber sect
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pure (sectionPackageName name sect, reverseDeps) :: Maybe (Text.Text, Natural))
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$ zip sectionNames sections
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where
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reverseLink = \case
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Tag.TagOpen "a" attrs -> mapFind attrReverseLink attrs
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_ -> Nothing
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attrReverseLink = \case
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("href", lnk) -> if
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| "packdeps.haskellers.com/reverse/" `Text.isInfixOf` lnk -> Just lnk
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| otherwise -> Nothing
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_ -> Nothing
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sectionPackageName :: Text -> [Tag] -> Text
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sectionPackageName sectionName = \case
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(_: Tag.TagText name : _) -> name
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(_: el : _) -> sectionName
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xs -> sectionName
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firstNaturalNumber :: [Tag] -> Maybe Natural
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firstNaturalNumber =
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mapFind (\case
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Tag.TagText t -> parseNat t
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_ -> Nothing)
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mapFind :: (a -> Maybe b) -> [a] -> Maybe b
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mapFind f xs = fromJust . f <$> List.find (isJust . f) xs
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