Re: pre-announce exmh-2.7.2

Tcl's variable tracing facility is powerful, but
it can also be heavy handed.  In this case the flist array
is being traced, so every update to any element fires (er, used to fire)
a procedure call that was really only interested in a slight
subset of the array.  I was doing all this at the same time as
the "array unset" optimizations that were also cleaning up code
that looked through a huge array just to operate on a small part of
it.  So, different cases, but similar issues of looking through
a large data structure when only a small fraction of it is
interesting.

>>>Chris Garrigues said:
 > > From:  [email protected]
 > > Date:  Thu, 06 Jan 2005 10:41:00 -0500
 > >
 > > Yeah, trace can be really handy for that.  The problem is that it ends
 > up being
 > > an awful lot like Intercal's 'come from' statement (the only other
 > actual
 > > implementation I've seen of it was the old IBM Fortran G compiler's
 > DEBUG
 > > stuff, which allowed stuff like 'AT 10' - though of course all the
 > Lisp-derived
 > > langages the whole *point* of the language is tacking that stuff onto
 > expre
 > > ssions
 > > with (cons (foo) (bar)) ;)
 > 
 > Oh, oh, you intuited that I spent years as a Lisp hacker.  I've been
 > exposed.
 > 
 > Lisp doesn't actually have too much of this kind of thing, but if you've
 > ever 
 > had the "pleasure" of looking at Prolog, it's nothing but this stuff.
 > 
 > Chris
 > 
 > -- 
 > Chris Garrigues                         Trinsic Solutions
 > President                               1611-B West 6th Street
 >                                         Austin, TX  78703-5074
 > 
 > 512-322-0180                            http://www.trinsics.com
 > 
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 >                 uptime or reactively pay for downtime?
 > 
 >                           Trinsic Solutions
 >                  Your Proactive IT Management Partner
 > 

--
Brent Welch
Software Architect, Panasas Inc
Delivering the premier storage system for scalable Linux clusters

www.panasas.com
[email protected]