Re: [Haskell-cafe] better error message for "undefined"

You can use the error function. It accepts a string that is displayed when the error is evaluated:

GHCi, version 6.10.1: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer ... linking ... done. Loading package base ... linking ... done. Prelude> error "hi!" *** Exception: hi!

HTH, Martijn. Andrew U. Frank wrote:

is there a way to have different kinds of undefined? such that i get a message which one was hit. something like writing in the code 'unefined 'my error 123' which prints 'undefined - my error 123' when it is accidentally hit.