Custom subcommands

[srid]

Allow users to add custom subcommands to the built executable.

[joelmccracken]

BTW this is something I want for myself too. Not sure what prompted you to make this issue but 👍

[srid]

I wanted to write a subcommand to be able to modify source files. Specifically to add a new entry to a .toml file (see below), but I imagine someone may want to use for other purposes, like create a new blog post draft with date and other template stuff automatically filled in.

Currently I hack around it like this:

main :: IO ()
main = do
  -- HACK: Until https://github.com/srid/rib/issues/80
  getArgs >>= \case
    ["tidbit", url] -> do
      -- TODO: Get og:title, og:image, etc..?
      today <- utctDay <$> getCurrentTime
      let tidbit = Tidbit today "TITLE" (toText url) [] Nothing
      modifyFile "a/tidbits.toml" $ \content ->
        toString $
          intercalate @Char
            "\n"
            [ "[[tidbit]]",
              toString $ Tidbit.toToml tidbit,
              content
            ]
    _ -> main'
  where
    modifyFile path f = do
      let tmpPath = path <> ".tmp"
      content <- f <$> readFile path
      writeFile tmpPath content
      copyFile tmpPath path
      removeFile tmpPath

main' :: IO ()
main' = Rib.run [reldir|a|] [reldir|b|] $ do
  Rib.buildStaticFiles [[relfile|static/**|]]
  [...]

[srid]

Consider using https://hackage.haskell.org/package/optparse-generic-1.3.1/docs/Options-Generic.html

[srid]

Turns out that this 'feature', as originally thought out, is unnecessarily complex as well.

All that rib needs to do is expose its own command line Parser type such that user applications can compose it as they wish, as part of their own CLI parsing mechanism.

[srid]

User-side composition will look like this: