Merge pull request #109 from chrisdone/cd/2025-11-10-subcommand-support

Add subcommand support

Author: chrisdone-artificial

examples/41-commands.hell

@@ -0,0 +1,37 @@
+-- --help:
+--
+-- Usage: <interactive> COMMAND
+--
+-- Available options:
+--   -h,--help                Show this help text
+--
+-- Available commands:
+--   add                      Add the thing
+--   remove
+--   list
+
+data Command
+  = Add Text
+  | Remove Text
+  | List
+
+parseAdd = Main.Add <$> Options.strArgument (Argument.metavar "FILE" <> Argument.help "File to add")
+
+parseRemove = Main.Remove <$> Options.strArgument (Argument.metavar "FILE" <> Argument.help "File to remove")
+
+parseList = Applicative.pure Main.List
+
+cmdParser =
+  Options.hsubparser
+    ( Options.command "add"    (Options.info Main.parseAdd    (Options.progDesc "Add the thing"))
+   <> Options.command "remove" (Options.info Main.parseRemove Options.fullDesc)
+   <> Options.command "list"   (Options.info Main.parseList   Options.fullDesc)
+    )
+
+main = do
+  let opts = Options.info (Main.cmdParser <**> Options.helper) Options.fullDesc
+  cmd <- Options.execParser opts
+  case cmd of
+    Add f    -> Text.putStrLn $ "Adding " <> f
+    Remove f -> Text.putStrLn $ "Removing " <> f
+    List     -> Text.putStrLn "Listing files"

src/Hell.hs

@@ -2076,12 +2076,16 @@ polyLits =
                "Options.flag'" Options.flag' :: forall a. a -> Options.Mod Options.FlagFields a -> Parser a
                "Option.long" option_long :: forall a. Text -> Options.Mod Options.OptionFields a
                "Option.help" options_help :: forall a. Text -> Options.Mod Options.OptionFields a
+               "Options.hsubparser" Options.hsubparser :: forall a. Options.Mod Options.CommandFields a -> Parser a
+               "Options.command" options_command :: forall a. Text -> Options.ParserInfo a -> Options.Mod Options.CommandFields a
                "Flag.help" options_help :: forall a. Text -> Options.Mod Options.FlagFields a
                "Flag.long" flag_long :: forall a. Text -> Options.Mod Options.FlagFields a
                "Option.value" option_value :: forall a. a -> Options.Mod Options.OptionFields a
                "Argument.value" argument_value :: forall a. a -> Options.Mod Options.ArgumentFields a
                "Argument.metavar" argument_metavar :: forall a. Text -> Options.Mod Options.ArgumentFields a
                "Argument.help" options_help :: forall a. Text -> Options.Mod Options.ArgumentFields a
+               "Options.progDesc" options_progDesc :: forall a. Text -> Options.InfoMod a
+               "Options.header" options_header :: forall a. Text -> Options.InfoMod a
              |]
       in toplevel
    )
@@ -2095,12 +2099,21 @@ argument_metavar = Options.metavar . Text.unpack
 option_value :: forall a. a -> Options.Mod Options.OptionFields a
 option_value = Options.value
 
+options_progDesc :: forall a. Text -> Options.InfoMod a
+options_progDesc = Options.progDesc . Text.unpack
+
+options_header :: forall a. Text -> Options.InfoMod a
+options_header = Options.header . Text.unpack
+
 argument_value :: forall a. a -> Options.Mod Options.ArgumentFields a
 argument_value = Options.value
 
 options_help :: forall f a. Text -> Options.Mod f a
 options_help = Options.help . Text.unpack
 
+options_command :: forall a. Text -> Options.ParserInfo a -> Options.Mod Options.CommandFields a
+options_command = Options.command . Text.unpack
+
 option_long :: forall a. Text -> Options.Mod Options.OptionFields a
 option_long = Options.long . Text.unpack