diff options
Diffstat (limited to 'users/aspen/xanthous/src/Xanthous/Util/Optparse.hs')
| -rw-r--r-- | users/aspen/xanthous/src/Xanthous/Util/Optparse.hs | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/users/aspen/xanthous/src/Xanthous/Util/Optparse.hs b/users/aspen/xanthous/src/Xanthous/Util/Optparse.hs new file mode 100644 index 0000000000..dfa6537235 --- /dev/null +++ b/users/aspen/xanthous/src/Xanthous/Util/Optparse.hs @@ -0,0 +1,21 @@ +-------------------------------------------------------------------------------- +module Xanthous.Util.Optparse + ( readWithGuard + ) where +-------------------------------------------------------------------------------- +import Xanthous.Prelude +-------------------------------------------------------------------------------- +import qualified Options.Applicative as Opt +-------------------------------------------------------------------------------- + +readWithGuard + :: Read b + => (b -> Bool) + -> (b -> String) + -> Opt.ReadM b +readWithGuard predicate errmsg = do + res <- Opt.auto + unless (predicate res) + $ Opt.readerError + $ errmsg res + pure res |