| -*- outline -*- |
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| * Overview |
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| This directory includes an example program for extending Guile with a |
| new (and even useful) data type, putting it into a shared library, so it |
| can be called from an unmodified guile interpreter. |
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| * Build Instructions |
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| To build the example, simply type |
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| make libbox |
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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 |
| 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. |
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| ** Usage |
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| 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: |
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| Extend your LD_LIBRARY_PATH variable (or equivalent) to include . and |
| .libs |
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| ** Example Session |
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| $ guile |
| guile> (load-extension "libbox" "scm_init_box") |
| 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) |
| $ |
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| * Module Installation |
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| If you like this example so much that you want to have it available |
| for normal usage, install the dynamic libraries in the .libs directory |
| to the directory $(prefix)/lib |
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