The Guile module system

In 1996 Tom Lord implemented a full-featured module system for Guile which allows loading Scheme source files into a private name space.

This module system is regarded as being rather idiosyncratic, and will probably change to something more like the ML module system, so for now I will simply descrive how it works for a couple of simple cases.

First of all, the Guile module system sets up a hierarchical name space, and that name space can be represented like Unix pathnames preceded by a # character. The root name space for all Guile-supplied modules is called ice-9.

So for example, the SLIB interface, contained in `$srcdir/ice-9/slib.scm', starts out with

(define-module (ice-9 slib))

and a user program can use

(use-modules (ice-9 slib))

to have access to all procedures and variables defined within the slib module with (define-public ...).

So here are the functions involved:

syntax: define-module module-specification

module-specification is of the form (hierarchy file). One example of this is

(use-modules (ice-9 slib))

define-module makes this module available to Guile programs under the given module-specification.

syntax: define-public ...

Makes a procedure or variable available to programs that use the current module.

syntax: use-modules module-specification

module-specification is of the form (hierarchy file). One example of this is

(use-modules (ice-9 slib))

use-modules allows the current Guile program to use all publicly defined procedures and variables in the module denoted by module-specification.

[FIXME: must say more, and explain, and also demonstrate a private name space use, and demonstrate how one would do Python's "from Tkinter import *" versus "import Tkinter". Must also add something about paths and standards for contributed modules.]

Some modules are included in the Guile distribution; here are references to the entries in this manual which describe them in more detail:

boot-9

boot-9 is Guile's initialization module, and it is always loaded when Guile starts up.

(ice-9 debug)

Mikael Djurfeldt's source-level debugging support for Guile (see section debugger user interface).

(ice-9 threads)

Guile's support for multi threaded execution (see section Threads and Dynamic Roots).

(ice-9 slib)

This module contains hooks for using Aubrey Jaffer's portable Scheme library SLIB from Guile (see section SLIB).

(ice-9 jacal)

This module contains hooks for using Aubrey Jaffer's symbolic math packge Jacal from Guile (see section JACAL).

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