let optparse-applicative handle the usage display when run w/o command or bad command

Still generating the list of commands myself, to get it sorted into
sections and with short synopses.
This commit is contained in:
Joey Hess 2015-07-09 11:49:52 -04:00
parent 6204dcbd7b
commit 8a9d2a6e9d
5 changed files with 42 additions and 30 deletions

View file

@ -13,9 +13,12 @@ import Types.Command
usageMessage :: String -> String
usageMessage s = "Usage: " ++ s
{- Usage message with lists of commands by section. -}
usage :: String -> [Command] -> String
usage header cmds = unlines $ usageMessage header : concatMap go [minBound..]
usage header cmds = unlines $ usageMessage header : commandList cmds
{- Commands listed by section, with breif usage and description. -}
commandList :: [Command] -> [String]
commandList cmds = concatMap go [minBound..]
where
go section
| null cs = []
@ -39,6 +42,7 @@ usage header cmds = unlines $ usageMessage header : concatMap go [minBound..]
longest f = foldl max 0 $ map (length . f) cmds
scmds = sort cmds
{- Descriptions of params used in usage messages. -}
paramPaths :: String
paramPaths = paramRepeating paramPath -- most often used