mirror of
https://git.savannah.gnu.org/git/guile.git
synced 2025-04-30 11:50:28 +02:00
673509f84f
safe/evil.scm, safe/README, modules/README, modules/main, modules/module-0.scm, modules/module-1.scm, modules/module-2.scm: Minor cleanup. * README: Added intro stuff, restructured a bit. * box-dynamic/README, box-module/README, box/README: Cleanup and restructuring. * box-dynamic-module/box-mixed.scm: New file, demonstrating usage of extension library functionality, but without exporting procedures from the library. Thanks to Thomas Wawrzinek for the idea and example code! * box-dynamic-module/box-module.scm: Add comments, export make-box, box-ref, box-set!. * box-dynamic-module/README: Integrate new module (box-mixed), restructure and cleanup a bit.
56 lines
1.4 KiB
Text
56 lines
1.4 KiB
Text
-*- outline -*-
|
|
|
|
* Overview
|
|
|
|
This directory includes an example program for extending Guile with a
|
|
new (and even useful) data type.
|
|
|
|
The `box' program created by this example is nearly identical to the
|
|
one produced in directory ../box, with one (important) difference: The
|
|
interpreter in this directory will place all defined primitive
|
|
procedures in a module called (box-module). That means that this
|
|
module must be used before the primitives can be accessed.
|
|
|
|
|
|
* Build Instructions
|
|
|
|
To build the example, simply type
|
|
|
|
make box
|
|
|
|
in this directory.
|
|
|
|
The resulting `box' program is a Guile interpreter which has one
|
|
additional data type called `box'.
|
|
|
|
|
|
* The Box Data Type
|
|
|
|
A box is simply an object for storing one other object in. It can be
|
|
used for passing parameters by reference, for example. You simply
|
|
store an object into a box, pass it to another procedure which can
|
|
store a new object into it and thus return a value via the box.
|
|
|
|
|
|
** Usage
|
|
|
|
Box objects are created with `make-box', set with `box-set!' and
|
|
examined with `box-ref'. Note that these procedures are placed in a
|
|
module called (box-module) and can thus only be accessed after using
|
|
this module. See the following example session for usage details:
|
|
|
|
|
|
** Example Session
|
|
|
|
$ ./box
|
|
guile> (use-modules (box-module))
|
|
guile> (define b (make-box))
|
|
guile> b
|
|
#<box #f>
|
|
guile> (box-set! b '(list of values))
|
|
guile> b
|
|
#<box (list of values)>
|
|
guile> (box-ref b)
|
|
(list of values)
|
|
guile> (quit)
|
|
$
|