Relude.Extra.CallStack

Contains useful functions to work with GHC callstack.

Documentation

ownName :: HasCallStack => String

This function returns the name of its caller function, but it requires that the caller function has HasCallStack constraint. Otherwise, it returns "unknown".

>>> foo :: HasCallStack => String; foo = ownName
>>> foo
"foo"
>>> bar :: HasCallStack => String; bar = foo
>>> bar
"foo"

callerName :: HasCallStack => String

This function returns the name of its caller of the caller function, but it requires that the caller function and caller of the caller function have HasCallStack constraint. Otherwise, it returns "unkown". It's useful for logging:

>>> log :: HasCallStack => String -> IO (); log s = putStrLn $ callerName ++ ":" ++ s
>>> greeting :: HasCallStack => IO (); greeting = log "Starting..." >> putStrLn "Hello!" >> log "Ending..."
>>> greeting
greeting:Starting...
Hello!
greeting:Ending...