Remove code duplication around version info.

Text.Pandoc.App.CommandLineOptions and pandoc-cli/src/pandoc.hs
had similar code for generating version information.

To avoid duplication, we now export `versionInfo` from
Text.Pandoc.App [API change]. (The function is reexported from the
non-public module Text.Pandoc.App.CommandLineOptions.)  This function
has three parameters that can be filled in when it is called by
pandoc-cli.

This change will make it simpler to revise version information.

pandoc-cli/src/pandoc.hs

@@ -16,17 +16,12 @@ module Main where
 import qualified Control.Exception as E
 import System.Environment (getArgs, getProgName)
 import Text.Pandoc.App ( convertWithOpts, defaultOpts, options
-                       , parseOptionsFromArgs, handleOptInfo )
+                       , parseOptionsFromArgs, handleOptInfo, versionInfo )
 import Text.Pandoc.Error (handleError)
-import System.Exit (exitSuccess)
 import Data.Monoid (Any(..))
 import PandocCLI.Lua
 import PandocCLI.Server
-import qualified Text.Pandoc.UTF8 as UTF8
-import Text.Pandoc.Version (pandocVersion)
-import Text.Pandoc.Data (defaultUserDataDir)
 import Text.Pandoc.Scripting (ScriptingEngine(..))
-import Data.Version (showVersion)
 import qualified Data.Text as T
 
 #ifdef NIGHTLY
@@ -51,7 +46,7 @@ main = E.handle (handleError . Left) $ do
   let hasVersion = getAny $ foldMap
          (\s -> Any (s == "-v" || s == "--version"))
          (takeWhile (/= "--") rawArgs)
-  let versionOr action = if hasVersion then versionInfo else action
+  let versionOr action = if hasVersion then versionInfoCLI else action
   case prg of
     "pandoc-server.cgi" -> versionOr runCGI
     "pandoc-server"     -> versionOr $ runServer rawArgs
@@ -67,37 +62,25 @@ main = E.handle (handleError . Left) $ do
             Left e -> handleOptInfo engine e
             Right opts -> convertWithOpts engine opts
 
-copyrightMessage :: String
-copyrightMessage =
- "Copyright (C) 2006-2024 John MacFarlane. Web: https://pandoc.org\n"
- ++
- "This is free software; see the source for copying conditions. There is no\n"
- ++
- "warranty, not even for merchantability or fitness for a particular purpose."
 
-flagSettings :: String
-flagSettings = "Features: " ++
+getFeatures :: [String]
+getFeatures = [
 #ifdef VERSION_pandoc_server
   "+server"
 #else
   "-server"
 #endif
-  ++ " " ++
+  ,
 #ifdef VERSION_hslua_cli
   "+lua"
 #else
   "-lua"
 #endif
+  ]
 
-versionInfo :: IO ()
-versionInfo = do
-  defaultDatadir <- defaultUserDataDir
+versionInfoCLI :: IO ()
+versionInfoCLI = do
   scriptingEngine <- getEngine
-  UTF8.putStr $ T.unlines $ map T.pack
-   [ "pandoc " ++ showVersion pandocVersion ++ versionSuffix
-   , flagSettings
-   , "Scripting engine: " ++ T.unpack (engineName scriptingEngine)
-   , "User data directory: " ++ defaultDatadir
-   , copyrightMessage
-   ]
-  exitSuccess
+  versionInfo getFeatures
+              (Just $ T.unpack (engineName scriptingEngine))
+              versionSuffix

src/Text/Pandoc/App.hs

@@ -26,6 +26,7 @@ module Text.Pandoc.App (
           , parseOptionsFromArgs
           , options
           , applyFilters
+          , versionInfo
           ) where
 import qualified Control.Exception as E
 import Control.Monad ( (>=>), when, forM, forM_ )
@@ -55,7 +56,7 @@ import Text.Pandoc.Image (svgToPng)
 import Text.Pandoc.App.Opt (Opt (..), LineEnding (..), defaultOpts,
                             IpynbOutput (..), OptInfo(..))
 import Text.Pandoc.App.CommandLineOptions (parseOptions, parseOptionsFromArgs,
-                                           options, handleOptInfo)
+                                           options, handleOptInfo, versionInfo)
 import Text.Pandoc.App.Input (InputParameters (..), readInput)
 import Text.Pandoc.App.OutputSettings (OutputSettings (..), optToOutputSettings,
                                        sandbox')

src/Text/Pandoc/App/CommandLineOptions.hs

@@ -21,6 +21,7 @@ module Text.Pandoc.App.CommandLineOptions (
           , options
           , engines
           , setVariable
+          , versionInfo
           ) where
 import Control.Monad.Trans
 import Control.Monad.State.Strict
@@ -46,6 +47,7 @@ import System.IO (stdout)
 import Text.DocTemplates (Context (..), ToContext (toVal), Val (..))
 import Text.Pandoc
 import Text.Pandoc.Builder (setMeta)
+import Data.Version (showVersion)
 import Text.Pandoc.App.Opt (Opt (..), LineEnding (..), IpynbOutput (..),
                             DefaultsState (..), applyDefaults,
                             fullDefaultsPath, OptInfo(..))
@@ -193,13 +195,7 @@ handleOptInfo engine info = E.handle (handleError . Left) $ do
                      ,"text-styles"])
                   ,confNumFormat = Generic
                   ,confTrailingNewline = True} sty
-    VersionInfo -> do
-      defaultDatadir <- defaultUserDataDir
-      UTF8.hPutStrLn stdout
-       $ T.pack
-       $ "pandoc " ++ T.unpack pandocVersionText ++
-         "\nUser data directory: " ++ defaultDatadir ++
-         ('\n':copyrightMessage)
+    VersionInfo -> versionInfo [] Nothing ""
     Help -> do
       prg <- getProgName
       UTF8.hPutStr stdout (T.pack $ usageMessage prg options)
@@ -1269,3 +1265,21 @@ normalizePath fp =
 #else
 normalizePath = id
 #endif
+
+-- | Print version information with customizable features and scripting engine
+versionInfo :: [String] -> Maybe String -> String -> IO ()
+versionInfo features mbScriptingEngineName suffix = do
+  defaultDatadir <- defaultUserDataDir
+  let featuresLine = if null features
+                       then []
+                       else ["Features: " ++ unwords features]
+  let scriptingLine = case mbScriptingEngineName of
+                        Nothing -> []
+                        Just name -> ["Scripting engine: " ++ name]
+  UTF8.putStr $ T.unlines $ map T.pack $
+    ["pandoc " ++ showVersion pandocVersion ++ suffix] ++
+    featuresLine ++
+    scriptingLine ++
+    ["User data directory: " ++ defaultDatadir,
+     copyrightMessage]
+  exitSuccess