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* box-dynamic-module/README: Use a better example for box-map, as suggested by Thomas Wawrzinek.
77 lines
2.1 KiB
Text
77 lines
2.1 KiB
Text
-*- outline -*-
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* Overview
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This directory includes an example program for extending Guile with a
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new (and even useful) data type, putting it into a shared library, so it
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can be called from an unmodified guile interpreter. Further, the shared
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library defines a new guile module.
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* Build Instructions
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To build the example, simply type
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make libbox-module
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in this directory.
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* The Box Data Type
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A box is simply an object for storing one other object in. It can be
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used for passing parameters by reference, for example. You simply
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store an object into a box, pass it to another procedure which can
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store a new object into it and thus return a value via the box.
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** Usage
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Box objects are created with `make-box', set with `box-set!' and
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examined with `box-ref'. Note that these procedures are placed in a
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module called (box-module) and can thus only be accessed after using
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this module. See the following example session for usage details.
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** The Module (box-module)
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Extend your LD_LIBRARY_PATH variable (or equivalent) to include . and
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.libs and make sure that your current working directory is the one
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this file is contained in.
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$ guile
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guile> (use-modules (box-module))
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guile> (define b (make-box))
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guile> b
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#<box #f>
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guile> (box-set! b '(list of values))
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guile> b
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#<box (list of values)>
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guile> (box-ref b)
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(list of values)
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guile> (quit)
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$
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** The Module (box-mixed)
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The following example uses the module (box-mixed), also included in
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this directory. It uses the shared library libbox-module like the
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module (box-module) above, but does not export the procedures from
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that module. It only implements some procedures for dealing with box
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objects.
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$ guile
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guile> (use-modules (box-mixed))
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guile> (define bl (make-box-list 1 2 3))
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guile> bl
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(#<box 1> #<box 2> #<box 3>)
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guile> (box-map 1+ bl)
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(#<box 2> #<box 3> #<box 4>)
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guile> (quit)
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$
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If you like this example so much that you want to have it available
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for normal usage, install the dynamic libraries in the .libs directory
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to the directory $(prefix)/lib and the scheme file `box-module.scm' in
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a directory in your GUILE_LOAD_PATH.
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