How to best add logging/debugging code?

[Derek Elkins]

On Thu, 27 Nov 2003 14:19:53 +0000
Malcolm Wallace <Malcolm.Wallace at cs.york.ac.uk> wrote:

> > > Is there a list of problems anywhere with using trace?  For 
> > > example does it affect evaluation order?
> 
> Apart from changing the evaluation order of expressions, trace has
> other drawbacks, noted I think by Lennart(?) but I can't remember
> exactly where.  One issue is this:
> 
> Consider an expression where the printable argument to 'trace' causes
> the evaluation of another expression which itself is defined using
> 'trace'.  The nested 'trace' outputs will appear interspersed with
> each other.  In recursive definitions this can become quite painful
> to disentangle.

trace is handy for quick debugging, but if you reach this point, HOOD
would probably be a better choice (or some of the other debugging
technologies, e.g. Buddha, Hat, HsDebug).