**
UNSW Prolog - written by Claue Sammut (UNSW).

There is a PROLOG system available on 68000s only. It is invoked by
the command:

prolog  file1 file2 ...

file1, file2, etc. contain Prolog programs to be loaded before the user is
asked to type a command. The -s option may also be specified to set the
Prolog stack size. For example:

prolog -s3000 file1

would set the stack size to 3000 units (default is 1000).


There are a number of differences to the Prolog described in
Clocksin and Mellish.

commands are of the form
                command!
        e.g.    load file! to read a program from a file.

commands:
        trace procedure; trace [procedure, procedure,  ..]
        untrace procedure; untrace [procedure, ..]
        listing :for a list of all clauses

statements are of the form
                statement.
        e.g.    green(peas).

questions are of the form
                question?
        e.g.    green(Z)?       gives all solutions ( does not wait).

operators differences
        /=  for \=
        no \==

comments        "% comment to end of line".

To exit, type '@Q' or 'halt!'.

Also available on the vaxes as ~drm/bin/unswprolog.

For more information see DRM.

KNOWN BUGS
----------
The PROLOG system is inclined to cause an 'invalid stream' abort (187) on exit.
It is safe to continue from this abort by selecting the DEBUG task (with
control-S 02), typing 'C' to continue the aborted task, and selecting the
CLI again (e.g. control-S 01).


