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how to set breakpoint at exception throw?
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Date: 2000-07-05 (22:16)
From: Jean-Christophe Filliatre <filliatr@c...>
Subject: Re: how to set breakpoint at exception throw?

> In general, you are right; the  problem is that I do not have access
> to the location in the source code where the exception happened. I'm
> interested in  the line  number and the  file name of  the statement
> that originally caused the exception. Example:

It should  be easy to do  with camlp4, since locations  in sources are
bound in the right hand sides of grammar rules. Thus, you just have to
overwrite the syntax of raise so that it actually raises the exception
together with its location, in an exception looking like

  exception LocatedException of exn * (int * int);;

Then, when you want to debug  your program, you compile it with camlp4
and that little extension, instead of ocamlc.

I'm not expert enough  in the use of camlp4 to give  the code for this
extension (by the way, there is no quotation for raising exception, as
far as I looked in the manual) but I'm sure that's no more than two or
three lines of  code. And I don't know if the  current file name being
parsed can be accessed. Surely Daniel will be of some help here if you
ask him.

Jean-Christophe Filliatre    
  Computer Science Laboratory   Phone (650) 859-5173
  SRI International             FAX   (650) 859-2844
  333 Ravenswood Ave.           email filliatr@csl.sri.com
  Menlo Park, CA 94025, USA     web   http://www.csl.sri.com/~filliatr