[plt-scheme] Development and Debugging

From: David J. Neu (djneu at att.net)
Date: Tue Dec 6 14:10:36 EST 2005

Hi Noel,

In general I agree, but sometimes we do make mitsakes or omissios in
application code, or in tests and therefore would like to be able to
identify the location of an error in the production system.

All kidding aside though, we've used PLT's ability to install our own
exception handler that saves error-traces to a log file.  It works
great, but it's too slow to leave in production code.

We're hoping that we're missing something and that there's a way
around this.


On Fri, Dec 02, 2005 at 03:21:04AM -0800, Noel Welsh wrote:
> Debugging is a problem not a solution
>   - Debugging code after release is a sign that the
> development process has failed.
>   - Debugging code at the whole program level is a sign
> that unit testing is inadequate.
> I follow a TDD process:
>   - I write tests at the module level
>   - I write code at the module level
>   - I alternate the above till all my tests pass and I am
> reasonably confident that my tests cover all cases
>   - When I write enough of an application to go end-to-end
> I implement functional tests (Selenium is good for web
> apps)
> If I see an error it is very easy to localise: whatever I
> changed last is broken.  I sometimes run tests from within
> DrScheme to get better error localisation -- which I take
> to be a sign that my unit testing is inadequate.  I have
> never used error trace.  
> I know that is not the answer you want, but in my
> experience (and opinion) build-and-fix is a fundamentally
> broken development process.  Better debuggers and tracing
> tools can't change this.
> HTH,
> Noel
> --- "David J. Neu" <djneu at att.net> wrote:
> ...
> > We're finding the debugging cycle to be very challenging
> > because we
> > can't run compiled code in the production system with
> > debug on because
> > it's really slow, therefore we don't get detailed error
> > messages,
> > i.e. error trace.
> >
> Email: noelwelsh <at> yahoo <dot> com   noel <at> untyped <dot> com
> AIM: noelhwelsh
> Blogs: http://monospaced.blogspot.com/  http://www.untyped.com/untyping/
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