Now here’s someone who gets what open source is all about:

ad_proc -private ad_try {code args} {

  @author rhs@mit.edu
  @creation-date 2000-09-09

  Executes $code, catches any exceptions thrown by ad_raise and runs
  any matching exception handlers.

<strong><em>  If you use this I will kill you.</em></strong>
} {
   ...
}

My emphasis. From exception-procs.tcl in OpenACS :)