G.I.S. Prolog Options

Global Options and Settings of G.I.S. Prolog

In the Main Menu of G.I.S. Prolog, the "Options" are:

• Language
• Use External Database for Clauses
• Use Disk file for Clause Database
• FONTS
• Colour Settings
• Internet browser program setting
• Notepad Editor program setting
• PAINT program setting
• Diagnostic level

REMARKS:

Using option "Use Disk File for Clause Database", the Prolog clauses may be stored in a disk file instead of RAM memory; this increases considerably the storage capacity of the Prolog system, at the expense of some loss of speed (not a lot, since hashing and indexing techniques are being used internally by G.I.S. Prolog to make this disk-based Clause database a very fast system).

The option "Use External Database for Clauses" does not refer to disk-file storage alone; An "external database" (in Visual Prolog's sense of the term) can also reside in RAM memory, and perform equally well (or better than) the "classical way" of storing clauses as asserted Prolog terms in memory. At the moment, internal hashing and indexing techniques are being tested in G.I.S. Prolog, and the outcome of these tests will influence the way hashing and indexing is implemented in future versions of G.I.S. Prolog. It is also desired to make such techniques visible and controllable by the user (e.g. in a similar way as hashing techniques in "Arity Prolog" are user-defined).

The "FONTS" option allows the re-definition of all the fonts used internally by the G.I.S. Prolog system, including the Editor's font.

The "Colour Settings" allow the re-definition of all the colours used internally by the G.I.S. Prolog system. (See the topic/button "COLOUR" for more details).

The "Internet browser program setting" option allows the user to select the preferred browser application (e.g. Internet Explorer, Mozilla, etc), occasionally invoked by G.I.S. Prolog for accessing certain URLs and HTML files.

The "Notepad Editor program setting" option allows selection of the preferred text-editor application (e.g. Windows notepad, "Metapad", etc), occasionally invoked by G.I.S. Prolog as an external text-file editor/viewer.

The "PAINT program setting" option allows selection of the preferred "*.BMP" Image-file editor application (e.g. "Ms Paint", etc), occasionally invoked by G.I.S. Prolog as an external image editor (e.g. for modifying the background of maps, graphs and other graphics objects in the "Net Graph Designer Tool").

Finally the "Diagnostic Level" option only exists for debugging and testing purposes: It is not expected that ordinary users can change this option, nor is it desirable (since it might cause a storm of diagnostic messages that are incomprehensible to the user). Therefore, a password-protection mechanism has been installed to access this option, and passwords are given only to very few selected "super-users" (typically close friends of the author).