include "LoggingJava"

importJava "org.slf4j.MDC" where
    get    :: String -> <Proc> Maybe String
    put    :: String -> String -> <Proc> ()
    remove :: String -> <Proc> ()

putOrRemove :: String -> Maybe String -> <Proc> ()
putOrRemove key (Just value) = put key value
putOrRemove key Nothing      = remove key

@inline
withContext :: String -> String -> (<e> a) -> <e,Proc> a
withContext key value procedure = result
  where
    oldValue = get key
    put key value
    result = procedure
    putOrRemove key oldValue