70b9df5ee9
dynamic-link and load-extension work without passing the .so or .dll as the shared library extension, so these have been dropped so the examples and test-suite work on Cygwin. Also update documentation and use the 'lib' prefix as that is what we commonly name the shared libraries.
884 lines
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884 lines
33 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<!-- Hand-written HTML -->
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<html>
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<head>
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<title>SWIG and Guile</title>
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<link rel="stylesheet" type="text/css" href="style.css">
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</head>
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<body bgcolor="#ffffff">
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<H1><a name="Guile"></a>23 SWIG and Guile</H1>
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<!-- INDEX -->
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<div class="sectiontoc">
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<ul>
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<li><a href="#Guile_nn1">Supported Guile Versions</a>
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<li><a href="#Guile_nn2">Meaning of "Module"</a>
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<li><a href="#Guile_nn3">Old GH Guile API</a>
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<li><a href="#Guile_nn4">Linkage</a>
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<ul>
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<li><a href="#Guile_nn5">Simple Linkage</a>
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<li><a href="#Guile_nn6">Passive Linkage</a>
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<li><a href="#Guile_nn7">Native Guile Module Linkage</a>
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<li><a href="#Guile_nn8">Old Auto-Loading Guile Module Linkage</a>
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<li><a href="#Guile_nn9">Hobbit4D Linkage</a>
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</ul>
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<li><a href="#Guile_nn10">Underscore Folding</a>
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<li><a href="#Guile_nn11">Typemaps</a>
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<li><a href="#Guile_nn12">Representation of pointers as smobs</a>
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<ul>
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<li><a href="#Guile_nn13">GH Smobs</a>
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<li><a href="#Guile_nn14">SCM Smobs</a>
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<li><a href="#Guile_nn15">Garbage Collection</a>
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</ul>
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<li><a href="#Guile_nn16">Exception Handling</a>
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<li><a href="#Guile_nn17">Procedure documentation</a>
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<li><a href="#Guile_nn18">Procedures with setters</a>
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<li><a href="#Guile_nn19">GOOPS Proxy Classes</a>
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<ul>
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<li><a href="#Guile_nn20">Naming Issues</a>
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<li><a href="#Guile_nn21">Linking</a>
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</ul>
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</ul>
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</div>
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<!-- INDEX -->
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<p>
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This section details guile-specific support in SWIG.
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<H2><a name="Guile_nn1"></a>23.1 Supported Guile Versions</H2>
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<p>
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SWIG works with Guile versions 1.8.x and 2.0.x. Support for version
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1.6.x has been dropped. The last version of SWIG that still works with
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Guile version 1.6.x is SWIG 2.0.9.
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<p>
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Note that starting with guile 2.0, the guile sources can be compiled for
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improved performance. This is currently not tested with swig
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so your mileage may vary. To be safe set environment variable
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GUILE_AUTO_COMPILE to 0 when using swig generated guile code.
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<H2><a name="Guile_nn2"></a>23.2 Meaning of "Module"</H2>
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<p>
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There are three different concepts of "module" involved, defined
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separately for SWIG, Guile, and Libtool. To avoid horrible confusion,
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we explicitly prefix the context, e.g., "guile-module".
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<H2><a name="Guile_nn3"></a>23.3 Old GH Guile API</H2>
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<p>Support for the guile GH wrapper code generation has been dropped. The last
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version of SWIG that can still generate guile GH wrapper code is 2.0.9. Please
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use that version if you really need the GH wrapper code.
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<p>Guile 1.8 and older could be interfaced using a two different api's, the SCM
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or the GH API. The GH interface to guile is deprecated. Read more about why in the
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<a href="http://www.gnu.org/software/guile/docs/docs-1.6/guile-ref/GH.html#GH">Guile manual</a>.
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<p>The SCM wrapper generation assumes a guile version >= 1.8 and has several advantages over
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the "-gh" wrapper generation including garbage collection and GOOPS support.
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<H2><a name="Guile_nn4"></a>23.4 Linkage</H2>
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<p>
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Guile support is complicated by a lack of user community cohesiveness,
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which manifests in multiple shared-library usage conventions. A set of
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policies implementing a usage convention is called a <b>linkage</b>.
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<H3><a name="Guile_nn5"></a>23.4.1 Simple Linkage</H3>
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<p>
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The default linkage is the simplest; nothing special is done. In this
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case the function <code>SWIG_init()</code> is exported. Simple linkage
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can be used in several ways:
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</p>
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<ul>
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<li><b>Embedded Guile, no modules.</b> You want to embed a Guile
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interpreter into your program; all bindings made by SWIG shall show up
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in the root module. Then call <code>SWIG_init()</code> in the
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<code>inner_main()</code> function. See the "simple" and "matrix" examples under
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<code>Examples/guile</code>.
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<li><p><b>Dynamic module mix-in.</b> You want to create a Guile module
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using <code>define-module</code>, containing both Scheme code and
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bindings made by SWIG; you want to load the SWIG modules as shared
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libraries into Guile.</p>
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<div class="targetlang">
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<pre>
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(define-module (my module))
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(define my-so (dynamic-link "./libexample.so"))
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(dynamic-call "SWIG_init" my-so) ; make SWIG bindings
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;; Scheme definitions can go here
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</pre>
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</div>
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<p>
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Newer Guile versions provide a shorthand for <code>dynamic-link</code>
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and <code>dynamic-call</code>:
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</p>
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<div class="targetlang">
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<pre>
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(load-extension "./libexample.so" "SWIG_init")
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</pre>
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</div>
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<p>
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A more portable approach would be to drop the shared library extension:
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</p>
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<div class="targetlang">
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<pre>
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(load-extension "./libexample" "SWIG_init")
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</pre>
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</div>
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<p>
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You need to explicitly export those bindings made by SWIG that you
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want to import into other modules:
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</p>
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<div class="targetlang">
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<pre>
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(export foo bar)
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</pre>
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</div>
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<p>
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In this example, the procedures <code>foo</code> and <code>bar</code>
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would be exported. Alternatively, you can export all bindings with the
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following module-system hack:
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</p>
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<div class="targetlang">
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<pre>
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(module-map (lambda (sym var)
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(module-export! (current-module) (list sym)))
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(current-module))
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</pre>
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</div>
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<p>SWIG can also generate this Scheme stub (from
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<code>define-module</code> up to <code>export</code>)
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semi-automagically if you pass it the command-line argument
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<code>-scmstub</code>. The code will be exported in a file called
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<code><i>module</i>.scm</code> in the directory specified by <code>-outdir</code>
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or the current directory if <code>-outdir</code> is not specified.
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Since SWIG doesn't know how
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to load your extension module (with <code>dynamic-link</code> or
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<code>load-extension</code>), you need to supply this
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information by including a directive like this in the interface file:
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</p>
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<div class="code">
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<pre>
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%scheme %{ (load-extension "./libexample.so" "SWIG_init") %}
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</pre>
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</div>
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<p>
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(The <code>%scheme</code> directive allows to insert arbitrary Scheme
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code into the generated file <code><var>module.scm</var></code>; it is
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placed between the <code>define-module</code> form and the
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<code>export</code> form.)
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</p>
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</ul>
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<p>If you want to include several SWIG modules, you would need to rename
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<code>SWIG_init</code> via a preprocessor define to avoid symbol
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clashes. For this case, however, passive linkage is available.
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<H3><a name="Guile_nn6"></a>23.4.2 Passive Linkage</H3>
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<p>Passive linkage is just like simple linkage, but it generates an
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initialization function whose name is derived from the module and
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package name (see below).
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<p>You should use passive linkage rather than simple linkage when you
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are using multiple modules.
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<H3><a name="Guile_nn7"></a>23.4.3 Native Guile Module Linkage</H3>
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<p>SWIG can also generate wrapper code that does all the Guile module
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declarations on its own if you pass it the <code>-Linkage
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module</code> command-line option. This requires Guile 1.5.0 or later.
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<p>The module name is set with the <code>-package</code> and
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<code>-module</code> command-line options. Suppose you want to define
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a module with name <code>(my lib foo)</code>; then you would have to
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pass the options <code>-package <var>my</var>/<var>lib</var> -module
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<var>foo</var></code>. Note that the last part of the name can also be set
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via the SWIG directive <code>%module</code>.
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<p>You can use this linkage in several ways:
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<ul>
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<li><b>Embedded Guile with SWIG modules.</b> You want to embed a Guile
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interpreter into your program; the SWIG bindings shall be put into
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different modules. Simply call the function
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<code>scm_init_<var>my</var>_<var>modules</var>_<var>foo</var>_module</code>
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in the <code>inner_main()</code> function.
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<li><b>Dynamic Guile modules.</b> You want to load the SWIG modules as
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shared libraries into Guile; all bindings are automatically put in
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newly created Guile modules.
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<div class="targetlang">
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<pre>
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(define my-so (dynamic-link "./libfoo.so"))
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;; create new module and put bindings there:
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(dynamic-call "scm_init_my_modules_foo_module" my-so)
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</pre>
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</div>
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Newer Guile versions have a shorthand procedure for this:
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<div class="targetlang">
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<pre>
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(load-extension "./libfoo.so" "scm_init_my_modules_foo_module")
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</pre>
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</div>
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</ul>
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<H3><a name="Guile_nn8"></a>23.4.4 Old Auto-Loading Guile Module Linkage</H3>
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<p>Guile used to support an autoloading facility for object-code
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modules. This support has been marked deprecated in version 1.4.1 and
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is going to disappear sooner or later. SWIG still supports building
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auto-loading modules if you pass it the <code>-Linkage ltdlmod</code>
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command-line option.
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<p>Auto-loading worked like this: Suppose a module with name <code>(my
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lib foo)</code> is required and not loaded yet. Guile will then search
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all directories in its search path
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for a Scheme file <code>my/modules/foo.scm</code> or a shared library
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<code><var>my</var>/<var>modules</var>/lib<var>foo</var>.so</code> (or
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<code><var>my</var>/<var>modules</var>/lib<var>foo</var>.la</code>;
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see the GNU libtool documentation). If a
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shared library is found that contains the symbol
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<code>scm_init_<var>my</var>_<var>modules</var>_<var>foo</var>_module</code>,
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the library is loaded, and the function at that symbol is called with
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no arguments in order to initialize the module.
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<p>When invoked with the <code>-Linkage ltdlmod</code> command-line
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option, SWIG generates an exported module initialization function with
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an appropriate name.
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<H3><a name="Guile_nn9"></a>23.4.5 Hobbit4D Linkage</H3>
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<p>
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The only other linkage supported at this time creates shared object
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libraries suitable for use by hobbit's <code>(hobbit4d link)</code>
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guile module. This is called the "hobbit" linkage, and requires also
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using the "-package" command line option to set the part of the module
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name before the last symbol. For example, both command lines:
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</p>
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<div class="shell">
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<pre>
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swig -guile -package my/lib foo.i
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swig -guile -package my/lib -module foo foo.i
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</pre>
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</div>
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<p>
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would create module <code>(my lib foo)</code> (assuming in the first
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case foo.i declares the module to be "foo"). The installed files are
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my/lib/libfoo.so.X.Y.Z and friends. This scheme is still very
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experimental; the (hobbit4d link) conventions are not well understood.
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</p>
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<H2><a name="Guile_nn10"></a>23.5 Underscore Folding</H2>
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<p>
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Underscores are converted to dashes in identifiers. Guile support may
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grow an option to inhibit this folding in the future, but no one has
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complained so far.
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<p>You can use the SWIG directives <code>%name</code> and
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<code>%rename</code> to specify the Guile name of the wrapped
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functions and variables (see CHANGES).
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<H2><a name="Guile_nn11"></a>23.6 Typemaps</H2>
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<p>
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The Guile module handles all types via typemaps. This
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information is read from <code>Lib/guile/typemaps.i</code>.
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Some non-standard typemap substitutions are supported:
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<ul>
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<li><code>$descriptor</code> expands to a type descriptor for use with
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the <code>SWIG_NewPointerObj()</code> and
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<code>SWIG_ConvertPtr</code> functions.
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<li>For pointer types, <code>$*descriptor</code> expands to a
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descriptor for the direct base type (i.e., one pointer is stripped),
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whereas <code>$basedescriptor</code> expands to a
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descriptor for the base type (i.e., all pointers are stripped).
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</ul>
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<p>A function returning <code>void</code> (more precisely, a function
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whose <code>out</code> typemap returns <code>SCM_UNSPECIFIED</code>) is
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treated as returning no values. In <code>argout</code> typemaps, one
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can use the macro <code>GUILE_APPEND_RESULT</code> in order to append
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a value to the list of function return values.
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<p>Multiple values can be passed up to Scheme in one of three ways:
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<ul>
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<li><p><em>Multiple values as lists.</em>
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By default, if more than one value is to
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be returned, a list of the values is created and returned; to switch
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back to this behavior, use</p>
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<div class="code">
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<pre>
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%values_as_list;</pre>
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</div>
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<li><p><em>Multiple values as vectors.</em>
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By issuing
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</p>
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<div class="code">
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<pre>
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%values_as_vector;</pre>
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</div>
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<p>
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vectors instead of lists will be used.
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<li><p><em>Multiple values for multiple-value continuations.</em>
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<strong>This is the most elegant way.</strong> By issuing
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</p>
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<div class="code">
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<pre>
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%multiple_values;</pre>
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</div>
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<p>
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multiple values are passed to the multiple-value
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continuation, as created by <code>call-with-values</code> or the
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convenience macro <code>receive</code>. The latter is available if you
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issue <code>(use-modules (srfi srfi-8))</code>. Assuming that your
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<code>divide</code> function
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wants to return two values, a quotient and a remainder, you can write:
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</p>
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<div class="targetlang">
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<pre>
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(receive (quotient remainder)
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(divide 35 17)
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<var>body</var>...)
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</pre>
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</div>
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<p>
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In <code><var>body</var></code>, the first result of
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<code>divide</code> will be bound to the variable
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<code>quotient</code>, and the second result to <code>remainder</code>.
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</p>
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|
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</ul>
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<p>
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See also the "multivalue" example.
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</p>
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<p>Constants are exported as a function that returns the value. The
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%feature("constasvar") can be applied to any constant, immutable variable, or enum.
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Instead of exporting the constant as a function that must be called, the
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constant will appear as a scheme variable. See
|
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<a href="Customization.html#Customization_features">Features and the %feature directive</a>
|
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for info on how to apply the %feature.</p>
|
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|
|
<H2><a name="Guile_nn12"></a>23.7 Representation of pointers as smobs</H2>
|
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|
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|
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<p>
|
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For pointer types, SWIG uses Guile smobs. SWIG smobs print
|
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like this: <code>#<swig struct xyzzy * 0x1234affe></code> Two of
|
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them are <code>equal?</code> if and only if they have the same type
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and value.
|
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<p>
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To construct a Scheme object from a C pointer, the wrapper code calls
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the function <code>SWIG_NewPointerObj()</code>, passing a pointer to a
|
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struct representing the pointer type. The type index to store in the
|
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upper half of the CAR is read from this struct.
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To get the pointer represented by a smob, the wrapper code calls the
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function <code>SWIG_ConvertPtr()</code>, passing a pointer to a struct
|
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representing the expected pointer type. See also
|
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<a href="Typemaps.html#Typemaps_runtime_type_checker">The run-time type checker</a>.
|
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If the Scheme object passed was not a SWIG smob representing a compatible
|
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pointer, a <code>wrong-type-arg</code> exception is raised.
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<H3><a name="Guile_nn13"></a>23.7.1 GH Smobs</H3>
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|
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<p>
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In earlier versions of SWIG, C pointers were represented as Scheme
|
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strings containing a hexadecimal rendering of the pointer value and a
|
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mangled type name. As Guile allows registering user types, so-called
|
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"smobs" (small objects), a much cleaner representation has been
|
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implemented now. The details will be discussed in the following.
|
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</p>
|
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<p> A smob is a cons cell where the lower half of the CAR contains the smob type
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tag, while the upper half of the CAR and the whole CDR are available. Every
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module creates its own smob type in the clientdata field of the module. So the
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lower 16 bits of the car of the smob store the tag and the upper 16 bits store
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the index this type is in the array. We can then, given a smob, find its
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swig_type_info struct by using the tag (lower 16 bits of car) to find which
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module this type is in (since each tag is unique for the module). Then we use
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the upper 16 bits to index into the array of types attached to this module.
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Looking up the module from the tag is worst case O(# of modules) but average
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case O(1). This is because the modules are stored in a circularly linked list,
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and when we start searching the modules for the tag, we start looking with the
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module that the function doing the lookup is in. SWIG_Guile_ConvertPtr() takes
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as its first argument the swig_module_info * of the calling function, which is
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where we start comparing tags. Most types will be looked up in the same module
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that created them, so the first module we check will most likely be correct.
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Once we have a swig_type_info structure, we loop through the linked list of
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casts, using pointer comparisons.</p>
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<H3><a name="Guile_nn14"></a>23.7.2 SCM Smobs</H3>
|
|
|
|
|
|
<p>The SCM interface (using the "-scm" argument to swig) uses swigrun.swg.
|
|
The whole type system, when it is first initialized, creates two smobs named "swig" and "collected_swig".
|
|
The swig smob is used for non-garbage collected smobs, while the collected_swig smob is used as described
|
|
below. Each smob has the same format, which is a double cell created by SCM_NEWSMOB2()
|
|
The first word of data is the pointer to the object and the second word of data is the swig_type_info *
|
|
structure describing this type. This is a lot easier than the GH interface above because we can store
|
|
a pointer to the type info structure right in the type. With the GH interface, there was not enough
|
|
room in the smob to store two whole words of data so we needed to store part of the "swig_type_info address"
|
|
in the smob tag. If a generated GOOPS module has been loaded, smobs will be wrapped by the corresponding
|
|
GOOPS class.</p>
|
|
|
|
|
|
<H3><a name="Guile_nn15"></a>23.7.3 Garbage Collection</H3>
|
|
|
|
|
|
<p>Garbage collection is a feature of the new SCM interface, and it is automatically included
|
|
if you pass the "-scm" flag to swig. Thus the swig garbage collection support requires guile >1.6.
|
|
Garbage collection works like this. Every swig_type_info structure stores in its clientdata field a pointer
|
|
to the destructor for this type. The destructor is the generated wrapper around the delete function.
|
|
So swig still exports a wrapper for the destructor, it just does not call scm_c_define_gsubr() for
|
|
the wrapped delete function. So the only way to delete an object is from the garbage collector, since the
|
|
delete function is not available to scripts. How swig determines if a type should be garbage collected
|
|
is exactly like described in <a href="Customization.html#Customization_ownership">
|
|
Object ownership and %newobject</a> in the SWIG manual. All typemaps use an $owner var, and
|
|
the guile module replaces $owner with 0 or 1 depending on feature:new.</p>
|
|
|
|
<H2><a name="Guile_nn16"></a>23.8 Exception Handling</H2>
|
|
|
|
|
|
<p>
|
|
SWIG code calls <code>scm_error</code> on exception, using the following
|
|
mapping:
|
|
|
|
<div class="code">
|
|
<pre>
|
|
MAP(SWIG_MemoryError, "swig-memory-error");
|
|
MAP(SWIG_IOError, "swig-io-error");
|
|
MAP(SWIG_RuntimeError, "swig-runtime-error");
|
|
MAP(SWIG_IndexError, "swig-index-error");
|
|
MAP(SWIG_TypeError, "swig-type-error");
|
|
MAP(SWIG_DivisionByZero, "swig-division-by-zero");
|
|
MAP(SWIG_OverflowError, "swig-overflow-error");
|
|
MAP(SWIG_SyntaxError, "swig-syntax-error");
|
|
MAP(SWIG_ValueError, "swig-value-error");
|
|
MAP(SWIG_SystemError, "swig-system-error");
|
|
</pre>
|
|
</div>
|
|
|
|
<p>
|
|
The default when not specified here is to use "swig-error".
|
|
See Lib/exception.i for details.
|
|
|
|
<H2><a name="Guile_nn17"></a>23.9 Procedure documentation</H2>
|
|
|
|
|
|
<p>If invoked with the command-line option <code>-procdoc
|
|
<var>file</var></code>, SWIG creates documentation strings for the
|
|
generated wrapper functions, describing the procedure signature and
|
|
return value, and writes them to <var>file</var>. You need Guile 1.4
|
|
or later to make use of the documentation files.
|
|
|
|
<p>SWIG can generate documentation strings in three formats, which are
|
|
selected via the command-line option <code>-procdocformat
|
|
<var>format</var></code>:
|
|
<ul>
|
|
<li><code>guile-1.4</code> (default): Generates a format suitable for Guile 1.4.
|
|
<li><code>plain</code>: Generates a format suitable for Guile 1.4.1 and
|
|
later.
|
|
<li><code>texinfo</code>: Generates texinfo source, which must be run
|
|
through texinfo in order to get a format suitable for Guile 1.4.1 and
|
|
later.
|
|
</ul>
|
|
|
|
<p>You need to register the generated documentation file with Guile
|
|
like this:
|
|
|
|
<div class="targetlang">
|
|
<pre>
|
|
(use-modules (ice-9 documentation))
|
|
(set! documentation-files
|
|
(cons "<var>file</var>" documentation-files))
|
|
</pre>
|
|
</div>
|
|
|
|
<p>Documentation strings can be configured using the Guile-specific
|
|
typemap argument <code>doc</code>. See <code>Lib/guile/typemaps.i</code> for
|
|
details.
|
|
|
|
<H2><a name="Guile_nn18"></a>23.10 Procedures with setters</H2>
|
|
|
|
|
|
<p>For global variables, SWIG creates a single wrapper procedure
|
|
<code>(<var>variable</var> :optional value)</code>, which is used for
|
|
both getting and setting the value. For struct members, SWIG creates
|
|
two wrapper procedures <code>(<var>struct</var>-<var>member</var>-get
|
|
pointer)</code> and <code>(<var>struct-member</var>-set pointer value)</code>.
|
|
|
|
<p>If invoked with the command-line option <code>-emit-setters</code>
|
|
(<em>recommended</em>),
|
|
SWIG will additionally create procedures with setters. For global
|
|
variables, the procedure-with-setter <code><var>variable</var></code>
|
|
is created, so you can use <code>(<var>variable</var>)</code> to get
|
|
the value and <code>(set! (<var>variable</var>)
|
|
<var>value</var>)</code> to set it. For struct members, the
|
|
procedure-with-setter <code><var>struct</var>-<var>member</var></code>
|
|
is created, so you can use <code>(<var>struct</var>-<var>member</var>
|
|
<var>pointer</var>)</code> to get the value and <code>(set!
|
|
(<var>struct</var>-<var>member</var> <var>pointer</var>)
|
|
<var>value</var>)</code> to set it.
|
|
|
|
<p>If invoked with the command-line option <code>-only-setters</code>,
|
|
SWIG will <em>only</em> create procedures with setters, i.e., for
|
|
struct members, the procedures <code>(<var>struct</var>-<var>member</var>-get
|
|
pointer)</code> and <code>(<var>struct-member</var>-set pointer
|
|
value)</code> are <em>not</em> generated.
|
|
|
|
<H2><a name="Guile_nn19"></a>23.11 GOOPS Proxy Classes</H2>
|
|
|
|
|
|
<p>SWIG can also generate classes and generic functions for use with
|
|
Guile's Object-Oriented Programming System (GOOPS). GOOPS is a
|
|
sophisticated object system in the spirit of the Common Lisp Object
|
|
System (CLOS).
|
|
|
|
<p>GOOPS support is
|
|
only available with the new SCM interface (enabled with the
|
|
<code>-scm</code> command-line option of SWIG). To enable GOOPS
|
|
support, pass the <code>-proxy</code> argument to
|
|
swig. This will export the GOOPS wrapper definitions into the
|
|
<code><i>module</i>.scm</code> file in the directory specified by -outdir or the
|
|
current directory. GOOPS support requires either passive or module linkage.</p>
|
|
|
|
<p>The generated file will contain definitions of GOOPS classes mimicking the C++ class hierarchy.
|
|
<p>Enabling GOOPS support implies <code>-emit-setters</code>.
|
|
|
|
<p>If <code>-emit-slot-accessors</code> is also passed as an argument,
|
|
then the generated file will contain accessor methods for all the
|
|
slots in the classes and for global variables. The input class</p>
|
|
<div class="code"><pre>
|
|
class Foo {
|
|
public:
|
|
Foo(int i) : a(i) {}
|
|
int a;
|
|
int getMultBy(int i) { return a * i; }
|
|
Foo getFooMultBy(int i) { return Foo(a * i); }
|
|
};
|
|
Foo getFooPlus(int i) { return Foo(a + i); }
|
|
</pre></div>
|
|
|
|
<p>
|
|
will produce (if <code>-emit-slot-accessors</code> is not passed as a parameter)
|
|
</p>
|
|
|
|
<div class="targetlang"><pre>
|
|
(define-class <Foo> (<swig>)
|
|
(a #:allocation #:swig-virtual
|
|
#:slot-ref primitive:Foo-a-get
|
|
#:slot-set! primitive:Foo-a-set)
|
|
#:metaclass <swig-metaclass>
|
|
#:new-function primitive:new-Foo
|
|
)
|
|
(define-method (getMultBy (swig_smob <Foo>) i)
|
|
(primitive:Foo-getMultBy (slot-ref swig_smob 'smob) i))
|
|
(define-method (getFooMultBy (swig_smob <Foo>) i)
|
|
(make <Foo> #:init-smob (primitive:Foo-getFooMultBy (slot-ref swig_smob 'smob) i)))
|
|
|
|
(define-method (getFooPlus i)
|
|
(make <Foo> #:init-smob (primitive:getFooPlus i)))
|
|
|
|
(export <Foo> getMultBy getFooMultBy getFooPlus )
|
|
</pre></div>
|
|
|
|
<p>
|
|
and will produce (if <code>-emit-slot-accessors</code> is passed as a parameter)
|
|
</p>
|
|
|
|
<div class="targetlang"><pre>
|
|
(define-class <Foo> (<swig>)
|
|
(a #:allocation #:swig-virtual
|
|
#:slot-ref primitive:Foo-a-get
|
|
#:slot-set! primitive:Foo-a-set
|
|
<b>#:accessor a</b>)
|
|
#:metaclass <swig-metaclass>
|
|
#:new-function primitive:new-Foo
|
|
)
|
|
(define-method (getMultBy (swig_smob <Foo>) i)
|
|
(primitive:Foo-getMultBy (slot-ref swig_smob 'smob) i))
|
|
(define-method (getFooMultBy (swig_smob <Foo>) i)
|
|
(make <Foo> #:init-smob (primitive:Foo-getFooMultBy (slot-ref swig_smob 'smob) i)))
|
|
|
|
(define-method (getFooPlus i)
|
|
(make <Foo> #:init-smob (primitive:getFooPlus i)))
|
|
|
|
(export <Foo> <b>a</b> getMultBy getFooMultBy getFooPlus )
|
|
</pre></div>
|
|
|
|
<p>
|
|
which can then be used by this code
|
|
</p>
|
|
|
|
<div class="targetlang"><pre>
|
|
;; not using getters and setters
|
|
(define foo (make <Foo> #:args '(45)))
|
|
(slot-ref foo 'a)
|
|
(slot-set! foo 'a 3)
|
|
(getMultBy foo 4)
|
|
(define foo2 (getFooMultBy foo 7))
|
|
(slot-ref foo 'a)
|
|
(slot-ref (getFooPlus foo 4) 'a)
|
|
|
|
;; using getters and setters
|
|
(define foo (make <Foo> #:args '(45)))
|
|
(a foo)
|
|
(set! (a foo) 5)
|
|
(getMultBy foo 4)
|
|
(a (getFooMultBy foo 7))
|
|
</pre></div>
|
|
|
|
<p>Notice that constructor arguments are passed as a list after the <code>#:args</code> keyword. Hopefully in
|
|
the future the following will be valid <code>(make <Foo> #:a 5 #:b 4)</code></p>
|
|
|
|
<p>Also note that the order the declarations occur in the .i file make a difference. For example,
|
|
</p>
|
|
|
|
<div class="code"><pre>
|
|
%module test
|
|
|
|
%{ #include "foo.h" %}
|
|
|
|
%inline %{
|
|
int someFunc(Foo &a) {
|
|
...
|
|
}
|
|
%}
|
|
|
|
%include "foo.h"
|
|
</pre></div>
|
|
|
|
<p>
|
|
This is a valid SWIG file it will work as you think it will for primitive support, but the generated
|
|
GOOPS file will be broken. Since the <code>someFunc</code> definition is parsed by SWIG before all the
|
|
declarations in foo.h, the generated GOOPS file will contain the definition of <code>someFunc()</code>
|
|
before the definition of <Foo>. The generated GOOPS file would look like
|
|
</p>
|
|
|
|
<div class="targetlang"><pre>
|
|
;;...
|
|
|
|
(define-method (someFunc (swig_smob <Foo>))
|
|
(primitive:someFunc (slot-ref swig_smob 'smob)))
|
|
|
|
;;...
|
|
|
|
(define-class <Foo> (<swig>)
|
|
;;...
|
|
)
|
|
|
|
;;...
|
|
</pre></div>
|
|
|
|
<p>
|
|
Notice that <Foo> is used before it is defined. The fix is to just put the
|
|
<code>%import "foo.h"</code> before the <code>%inline</code> block.
|
|
</p>
|
|
|
|
<H3><a name="Guile_nn20"></a>23.11.1 Naming Issues</H3>
|
|
|
|
|
|
<p>As you can see in the example above, there are potential naming conflicts. The default exported
|
|
accessor for the <code>Foo::a</code> variable is named <code>a</code>. The name of the wrapper global
|
|
function is <code>getFooPlus</code>.
|
|
If the <code>-useclassprefix</code> option is passed to swig, the name of all accessors and member
|
|
functions will be prepended with the class name. So the accessor will be called <code>Foo-a</code> and
|
|
the member functions will be called <code>Foo-getMultBy</code>. Also, if the
|
|
<code>-goopsprefix goops:</code> argument is passed to swig, every identifier will be prefixed by
|
|
<code>goops:</code></p>
|
|
|
|
<p>Two guile-modules are created by SWIG. The first module contains the primitive definitions
|
|
of all the wrapped functions and variables, and is located either in the _wrap.cxx file (with <code>-Linkage
|
|
module</code>) or in the scmstub file (if <code>-Linkage passive -scmstub</code>). The name of this
|
|
guile-module is the swig-module name (given on the command line with the -module argument or with the
|
|
%module directive) concatenated with the string "-primitive". For
|
|
example, if <code>%module Test</code> is set in the swig interface file, the name of the guile-module in
|
|
the scmstub or <code>-Linkage module</code> will be <code>Test-primitive</code>. Also, the scmstub
|
|
file will be named <code>Test-primitive.scm</code>.
|
|
The string "primitive" can be changed by the <code>-primsuffix</code> swig
|
|
argument. So the same interface, with the <code>-primsuffix base</code> will produce a module called
|
|
<code>Test-base</code>.
|
|
The second generated guile-module contains all the GOOPS class definitions and is located in
|
|
a file named <i>module</i>.scm in the directory specified with -outdir or the current directory.
|
|
The name of this guile-module is the name of the
|
|
swig-module (given on the command line or with the <code>%module</code> directive).
|
|
In the previous example, the GOOPS definitions will be in a file named Test.scm.</p>
|
|
|
|
<p>Because of the naming conflicts, you can't in general use both the <code>-primitive</code> and the GOOPS
|
|
guile-modules at the same time. To do this, you need to rename the exported symbols from one or both
|
|
guile-modules. For example,</p>
|
|
<div class="targetlang"><pre>
|
|
(use-modules ((Test-primitive) #:renamer (symbol-prefix-proc 'primitive:)))
|
|
(use-modules ((Test) #:renamer (symbol-prefix-proc 'goops:)))
|
|
</pre></div>
|
|
|
|
<H3><a name="Guile_nn21"></a>23.11.2 Linking</H3>
|
|
|
|
|
|
<p>The guile-modules generated above all need to be linked together. GOOPS support requires
|
|
either passive or module linkage. The exported GOOPS guile-module will be the name of the swig-module
|
|
and should be located in a file called <i>Module</i>.scm. This should be installed on the autoload
|
|
path for guile, so that <code>(use-modules (<i>Package Module</i>))</code> will load everything needed.
|
|
Thus, the top of the GOOPS guile-module will contain code to load everything needed by the interface
|
|
(the shared library, the scmstub module, etc.).
|
|
The <code>%goops</code> directive inserts arbitrary code into the generated GOOPS guile-module, and
|
|
should be used to load the dependent libraries.</p>
|
|
|
|
<p>This breaks up into three cases</p>
|
|
<ul>
|
|
<li><b>Passive Linkage without -scmstub</b>: Note that this linkage style has the potential for naming
|
|
conflicts, since the primitive exported function and variable names are not wrapped in a guile-module
|
|
and might conflict with names from the GOOPS guile-module (see above). Pass the -goopsprefix
|
|
argument to solve this problem. If the <code>-exportprimitive</code> option is passed to SWIG the
|
|
<code>(export ...)</code> code that would be exported into the scmstub file is exported at the bottom
|
|
of the generated GOOPS guile-module.
|
|
The <code>%goops</code> directive should contain code to load the shared library.
|
|
|
|
<div class="code"><pre>
|
|
%goops %{ (load-extension "./libfoo.so" "scm_init_my_modules_foo_module") %}
|
|
</pre></div>
|
|
|
|
<p>
|
|
Produces the following code at the top of the generated GOOPS guile-module
|
|
(with the <code>-package my/modules -module foo</code> command line arguments)
|
|
</p>
|
|
|
|
<div class="targetlang"><pre>
|
|
(define-module (my modules foo))
|
|
|
|
;; %goops directive goes here
|
|
(load-extension "./libfoo.so" "scm_init_my_modules_foo_module")
|
|
|
|
(use-modules (oop goops) (Swig common))
|
|
</pre></div>
|
|
</li>
|
|
|
|
<li><p><b>Passive Linkage with -scmstub</b>: Here, the name of the scmstub file should be
|
|
<code>Module-primitive.scm</code> (with <i>primitive</i> replaced with whatever is given with the <code>-primsuffix</code>
|
|
argument. The code to load the shared library should be located in the <code>%scheme</code> directive,
|
|
which will then be added to the scmstub file.
|
|
SWIG will automatically generate the line <code>(use-modules (<i>Package</i> <i>Module-primitive</i>))</code>
|
|
into the GOOPS guile-module. So if <i>Module-primitive.scm</i> is on the autoload path for guile, the
|
|
<code>%goops</code> directive can be empty. Otherwise, the <code>%goops</code> directive should contain
|
|
whatever code is needed to load the <i>Module-primitive.scm</i> file into guile.</p>
|
|
|
|
<div class="targetlang"><pre>
|
|
%scheme %{ (load-extension "./libfoo.so" "scm_init_my_modules_foo_module") %}
|
|
// only include the following definition if (my modules foo) cannot
|
|
// be loaded automatically
|
|
%goops %{
|
|
(primitive-load "/path/to/foo-primitive.scm")
|
|
(primitive-load "/path/to/Swig/common.scm")
|
|
%}
|
|
</pre></div>
|
|
|
|
<p>
|
|
Produces the following code at the top of the generated GOOPS guile-module
|
|
</p>
|
|
|
|
<div class="targetlang"><pre>
|
|
(define-module (my modules foo))
|
|
|
|
;; %goops directive goes here (if any)
|
|
(primitive-load "/path/to/foo-primitive.scm")
|
|
(primitive-load "/path/to/Swig/common.scm")
|
|
|
|
(use-modules (oop goops) (Swig common))
|
|
(use-modules ((my modules foo-primitive) :renamer (symbol-prefix-proc
|
|
'primitive:)))
|
|
|
|
</pre></div>
|
|
</li>
|
|
|
|
<li><p><b>Module Linkage</b>: This is very similar to passive linkage with a scmstub file.
|
|
SWIG will also automatically generate the line <code>(use-modules
|
|
(<i>Package</i> <i>Module-primitive</i>))</code> into the GOOPS guile-module. Again the <code>%goops</code>
|
|
directive should contain whatever code is needed to get that module loaded into guile.</p>
|
|
|
|
<div class="code"><pre>
|
|
%goops %{ (load-extension "./libfoo.so" "scm_init_my_modules_foo_module") %}
|
|
</pre></div>
|
|
|
|
<p>
|
|
Produces the following code at the top of the generated GOOPS guile-module
|
|
</p>
|
|
|
|
<div class="targetlang"><pre>
|
|
(define-module (my modules foo))
|
|
|
|
;; %goops directive goes here (if any)
|
|
(load-extension "./libfoo.so" "scm_init_my_modules_foo_module")
|
|
|
|
(use-modules (oop goops) (Swig common))
|
|
(use-modules ((my modules foo-primitive) :renamer (symbol-prefix-proc
|
|
'primitive:)))
|
|
|
|
</pre></div>
|
|
</li>
|
|
</ul>
|
|
|
|
<p><b>(Swig common)</b>: The generated GOOPS guile-module also imports definitions from the
|
|
(Swig common) guile-module.
|
|
This module is included with SWIG and should be installed by SWIG into the autoload path for
|
|
guile (based on the configure script and whatever arguments are passed). If it is not, then the
|
|
<code>%goops</code> directive also needs to contain code to load the <code>common.scm</code> file
|
|
into guile. Also note that if you are trying to install the generated wrappers on a computer without
|
|
SWIG installed, you will need to include the common.swg file along with the install.</p>
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<p><b>Multiple Modules</b>: Type dependencies between modules is supported. For example, if
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<code>mod1</code> includes definitions of some classes, and <code>mod2</code> includes some classes
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derived from classes in <code>mod1</code>, the generated GOOPS file for <code>mod2</code> will declare
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the correct superclasses. The only problem is that since <code>mod2</code> uses symbols from
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<code>mod1</code>, the <code>mod2</code> GOOPS file must include a <code>(use-modules (mod2))</code>.
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Currently, SWIG does not automatically export this line; it must be included in the <code>%goops</code>
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directive of <code>mod2</code>. Maybe in the future SWIG can detect dependencies and export this line.
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(how do other language modules handle this problem?)</p>
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</body>
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</html>
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