2.3 Initialisation files and goals

Using command-line arguments (see section 2.4), SWI-Prolog can be forced to load files and execute queries for initialisation purposes or non-interactive operation. The most commonly used options are -f file or -s file to make Prolog load a file, -g goal to define an initialisation goal and -t goal to define the top-level goal. The following is a typical example for starting an application directly from the command-line.

machine% pl -s load.pl -g go -t halt

It tells SWI-Prolog to load load.pl, start the application using the entry-point go/0 and ---instead of entering the interactive top-level--- exit after completing go/0 . The -q may be used to suppress all informational messages.

In MS-Windows, the same can be achieved using a short-cut with appropriately defined command-line arguments. A typically seen alternative is to write a file run.pl with content as illustrated below. Double-clicking run.pl will start the application.

:- [load].                      % load program
:- go.                          % run it
:- halt.                        % and exit

Section discusses further scripting options and chapter 10 discusses the generation of runtime executables. Runtime executables are a mean to deliver executables that do not require the Prolog system.