etrace - Graphical Prolog Tracer in Emacs
First, an important observation: "Tracing"
is not synonymous with "debugging"! In Prolog, there
powerful declarative debugging
methods that help you much more than tracing.
Still, to augment the textual Prolog tracer's output with
positional information, download the Prolog
library etrace.pl to your program
directory, and add to your Prolog program:
To use that information in Emacs,
copy etrace.el to your
load path and add to your .emacs:
Restart Emacs, open a Prolog program that contains a
:- use_module(etrace) declaration,
do M-x etrace RET and enter a query to start
tracing a goal in that file.
You can also use the positional information emitted from an
existing shell buffer or Prolog process created by the Prolog
editing mode: Switch to the process buffer and do
M-x etrace-attach RET.
A screenshot: etrace.png.
An example Prolog file is turing.pl.
M-x etrace RET turing(, Ts) RET
More about Prolog: The Power of Prolog