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diff --git a/src/FSD/Package.hs b/src/FSD/Package.hs
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+{-
+Copyright (C) 2022 Yuchen Pei.
+
+This file is part of fsd.
+
+fsd is free software: you can redistribute it and/or modify it under
+the terms of the GNU Affero General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+fsd is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General
+Public License for more details.
+
+You should have received a copy of the GNU Affero General Public
+License along with fsd.  If not, see <https://www.gnu.org/licenses/>.
+
+-}
+
+{-# LANGUAGE ImportQualifiedPost #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module FSD.Package where
+
+import Data.Generics
+import Data.Maybe
+import Data.Text (Text)
+import Data.Text qualified as T
+import Debian.Control
+import Text.Regex.TDFA
+import FSD.Types
+
+getTags :: Paragraph -> [Text]
+getTags para = case fieldValue "Tag" para of
+  Nothing -> []
+  Just tags ->
+    (T.splitOn ", " . T.pack . concat . lines) tags
+
+{-package version should be from Source field overriding Version field:
+Package: pandoc
+Source: pandoc (2.9.2.1-1)
+Version: 2.9.2.1-1+b1
+-}
+getPackage :: Paragraph -> Maybe Package
+getPackage para = do
+  package <- T.pack <$> fieldValue "Package" para
+  let homepage = T.pack <$> fieldValue "Homepage" para
+  let tags = getTags para
+  let srcVersion = extractSrcVersion =<< fieldValue "Source" para
+  version <- T.pack <$> orElse srcVersion (fieldValue "Version" para)
+  return $ Package package version homepage (Tags tags)
+  where
+    extractSrcVersion :: String -> Maybe String
+    extractSrcVersion source =
+      case source =~ (".*\\((.*)\\)$" :: String) :: [[String]] of
+        [[_, version]] -> Just version
+        _ -> Nothing
+
+getPackages :: Control -> [Package]
+getPackages = catMaybes . fmap getPackage . unControl