Autogenerate list of formats for --help

shellcheck.hs

@@ -35,6 +35,7 @@ import Data.Bits
 import Data.Char
 import Data.Functor
 import Data.Either
+import Data.List
 import qualified Data.Map as Map
 import Data.Maybe
 import Data.Monoid
@@ -77,8 +78,8 @@ options = [
  Option "e" ["exclude"]
  (ReqArg (Flag "exclude") "CODE1,CODE2..") "exclude types of warnings",
  Option "f" ["format"]
- (ReqArg (Flag "format") "FORMAT")
- "output format (checkstyle, gcc, json, tty)",
+ (ReqArg (Flag "format") "FORMAT") $
+ "output format (" ++ formatList ++ ")",
  Option "C" ["color"]
  (OptArg (maybe (Flag "color" "always") (Flag "color")) "WHEN")
  "Use color (auto, always, never)",
@@ -109,6 +110,10 @@ formats options = Map.fromList [
  ("tty", ShellCheck.Formatter.TTY.format options)
  ]
 
+formatList = intercalate ", " names
+ where
+ names = Map.keys $ formats (formatterOptions defaultOptions)
+
 getOption [] _ = Nothing
 getOption (Flag var val:_) name | name == var = return val
 getOption (_:rest) flag = getOption rest flag