Starting Prolog

If you are using Windows, the batch file runtime-directory\qpvars.bat needs to be executed to set up the necessary environment variables. If you are using UNIX, your PATH environment variable needs to include the directory containing the Quintus tools.

To start Prolog, type prolog at the operating system prompt (whether UNIX or Windows):

     % prolog

The system responds by displaying a copyright message followed by the main Prolog prompt, as shown below.

     Quintus Prolog Release 3.5 (Sun 4, SunOS 5.5)
     | ?-

The | ?- is the main Prolog prompt. It indicates that you are at the top level of the Prolog system. At this point, the system is waiting for you to type a goal, such as a command to load a previously created file containing a Prolog program.

If you are using Windows, it is probably more useful to run qpwin from the Start Menu. This has the same appearance as the console-based version, except that the output is directed to a window. The properties of this window can be tuned; see too-too-prolog. If you use qpwin you do not need to run the runtime-directory\qpvars.bat batch file.