how to display line numbers of errors

I'm hacking in Racket and I keep getting errors.

The default error handler shows a s开发者_运维技巧tack trace. At the end of the stack trace, it shows the "top level" evaluation as "/path/to/file/my_module.rkt: [running body]"

How do I show the line number for the running body part?

If you use DrRacket, it will highlight the error location in the source. To get similar functionality in the racket REPL, see the errortrace tool.