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diff --git a/Doc/Manual/Chicken.html b/Doc/Manual/Chicken.html deleted file mode 100644 index 3a80811bd..000000000 --- a/Doc/Manual/Chicken.html +++ /dev/null @@ -1,597 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> -<html> -<head> -<title>SWIG and Chicken</title> -<link rel="stylesheet" type="text/css" href="style.css"> -<meta http-equiv="content-type" content="text/html; charset=UTF-8"> -</head> - -<body bgcolor="#ffffff"> - -<H1><a name="Chicken">23 SWIG and Chicken</a></H1> -<!-- INDEX --> -<div class="sectiontoc"> -<ul> -<li><a href="#Chicken_nn2">Preliminaries</a> -<ul> -<li><a href="#Chicken_nn3">Running SWIG in C mode</a> -<li><a href="#Chicken_nn4">Running SWIG in C++ mode</a> -</ul> -<li><a href="#Chicken_nn5">Code Generation</a> -<ul> -<li><a href="#Chicken_nn6">Naming Conventions</a> -<li><a href="#Chicken_nn7">Modules</a> -<li><a href="#Chicken_nn8">Constants and Variables</a> -<li><a href="#Chicken_nn9">Functions</a> -<li><a href="#Chicken_nn10">Exceptions</a> -</ul> -<li><a href="#Chicken_nn11">TinyCLOS</a> -<li><a href="#Chicken_nn12">Linkage</a> -<ul> -<li><a href="#Chicken_nn13">Static binary or shared library linked at compile time</a> -<li><a href="#Chicken_nn14">Building chicken extension libraries</a> -<li><a href="#Chicken_nn15">Linking multiple SWIG modules with TinyCLOS</a> -</ul> -<li><a href="#Chicken_nn16">Typemaps</a> -<li><a href="#Chicken_nn17">Pointers</a> -<ul> -<li><a href="#Chicken_collection">Garbage collection</a> -</ul> -<li><a href="#Chicken_nn18">Unsupported features and known problems</a> -<ul> -<li><a href="#Chicken_nn19">TinyCLOS problems with Chicken version <= 1.92</a> -</ul> -</ul> -</div> -<!-- INDEX --> - - - - <p> - This chapter describes SWIG's support of CHICKEN. CHICKEN is a - Scheme-to-C compiler supporting most of the language features as - defined in the <i>Revised^5 Report on Scheme</i>. Its main - attributes are that it - </p> - - <ol> - <li>generates portable C code</li> - <li>includes a customizable interpreter</li> - <li>links to C libraries with a simple Foreign Function Interface</li> - <li>supports full tail-recursion and first-class continuations</li> - </ol> - - <p> - When confronted with a large C library, CHICKEN users can use - SWIG to generate CHICKEN wrappers for the C library. However, - the real advantages of using SWIG with CHICKEN are its - <strong>support for C++</strong> -- object-oriented code is - difficult to wrap by hand in CHICKEN -- and its <strong>typed - pointer representation</strong>, essential for C and C++ - libraries involving structures or classes. - - </p> - -<H2><a name="Chicken_nn2">23.1 Preliminaries</a></H2> - - - <p> - CHICKEN support was introduced to SWIG in version 1.3.18. SWIG - relies on some recent additions to CHICKEN, which are only - present in releases of CHICKEN with version number - <strong>greater than or equal to 1.89</strong>. - To use a chicken version between 1.40 and 1.89, see the <a href="#Chicken_collection">Garbage collection</a> - section below. - </p> - - <p> - You may want to look at any of the examples in Examples/chicken/ - directory for the basic steps to run SWIG CHICKEN. - </p> - -<H3><a name="Chicken_nn3">23.1.1 Running SWIG in C mode</a></H3> - - - <p> - To run SWIG CHICKEN in C mode, use - the -chicken option. - </p> - - <div class="shell"> - <pre>% swig -chicken example.i</pre> - </div> - - <p> - To allow the wrapper to take advantage of future CHICKEN code - generation improvements, part of the wrapper is direct CHICKEN - function calls (<tt>example_wrap.c</tt>) and part is CHICKEN - Scheme (<tt>example.scm</tt>). The basic Scheme code must - be compiled to C using your system's CHICKEN compiler or - both files can be compiled directly using the much simpler <tt>csc</tt>. - </p> - - <div class="shell"> -<pre> -% chicken example.scm -output-file oexample.c -</pre> - </div> - - <p> - So for the C mode of SWIG CHICKEN, <tt>example_wrap.c</tt> and - <tt>oexample.c</tt> are the files that must be compiled to - object files and linked into your project. - </p> - -<H3><a name="Chicken_nn4">23.1.2 Running SWIG in C++ mode</a></H3> - - - <p> - To run SWIG CHICKEN in C++ mode, use - the -chicken -c++ option. - </p> - - <div class="shell"> - <pre>% swig -chicken -c++ example.i</pre> - </div> - - <p> - This will generate <tt>example_wrap.cxx</tt> and - <tt>example.scm</tt>. The basic Scheme code must be - compiled to C using your system's CHICKEN compiler or - both files can be compiled directly using the much simpler <tt>csc</tt>. - </p> - - <div class="shell"> - <pre>% chicken example.scm -output-file oexample.c</pre> - </div> - - <p> - So for the C++ mode of SWIG CHICKEN, <tt>example_wrap.cxx</tt> - and <tt>oexample.c</tt> are the files that must be compiled to - object files and linked into your project. - </p> - -<H2><a name="Chicken_nn5">23.2 Code Generation</a></H2> - - -<H3><a name="Chicken_nn6">23.2.1 Naming Conventions</a></H3> - - - <p> - Given a C variable, function or constant declaration named - <tt>Foo_Bar</tt>, the declaration will be available - in CHICKEN as an identifier ending with - <tt>Foo-Bar</tt>. That is, an underscore is converted - to a dash. - </p> - - <p> - You may control what the CHICKEN identifier will be by using the - <tt>%rename</tt> SWIG directive in the SWIG interface file. - </p> - -<H3><a name="Chicken_nn7">23.2.2 Modules</a></H3> - - - <p> - The name of the module must be declared one of two ways: - <ul> - <li>Placing <tt>%module example</tt> in the SWIG interface - file.</li> - <li>Using <tt>-module example</tt> on the SWIG command - line.</li> - </ul> - - <p> - The generated example.scm file then exports <code>(declare (unit modulename))</code>. - If you do not want SWIG to export the <code>(declare (unit modulename))</code>, pass - the -nounit option to SWIG. - - <p> - CHICKEN will be able to access the module using the <code>(declare - (uses <i>modulename</i>))</code> CHICKEN Scheme form. - </p> - -<H3><a name="Chicken_nn8">23.2.3 Constants and Variables</a></H3> - - - <p> - Constants may be created using any of the four constructs in - the interface file: - </p> - <ol> - <li><code>#define MYCONSTANT1 ...</code></li> - <li><code>%constant int MYCONSTANT2 = ...</code></li> - <li><code>const int MYCONSTANT3 = ...</code></li> - <li><code>enum { MYCONSTANT4 = ... };</code></li> - </ol> - - <p> - In all cases, the constants may be accessed from within CHICKEN - using the form <tt>(MYCONSTANT1)</tt>; that is, the constants - may be accessed using the read-only parameter form. - </p> - - <p> - Variables are accessed using the full parameter form. - For example, to set the C variable "int my_variable;", use the - Scheme form <tt>(my-variable 2345)</tt>. To get the C variable, - use <tt>(my-variable)</tt>. - </p> - - <p> - The <tt>%feature("constasvar")</tt> can be applied to any constant - or immutable variable. Instead of exporting the constant as - a function that must be called, the constant will appear as a - scheme variable. This causes the generated .scm file to just contain the code - <tt>(set! MYCONSTANT1 (MYCONSTANT1))</tt>. See - <a href="Customization.html#Customization_features">Features and the %feature directive</a> - for info on how to apply the %feature. - </p> - -<H3><a name="Chicken_nn9">23.2.4 Functions</a></H3> - - - <p> - C functions declared in the SWIG interface file will have - corresponding CHICKEN Scheme procedures. For example, the C - function "int sqrt(double x);" will be available using the - Scheme form <tt>(sqrt 2345.0)</tt>. A <code>void</code> return - value will give C_SCHEME_UNDEFINED as a result. - </p> - <p> - A function may return more than one value by using the - <code>OUTPUT</code> specifier (see Lib/chicken/typemaps.i). - They will be returned as multiple values using <code>(values)</code> if there is more than one - result (that is, a non-void return value and at least one argout - parameter, or a void return value and at least two argout - parameters). The return values can then be accessed with <code>(call-with-values)</code>. - </p> - -<H3><a name="Chicken_nn10">23.2.5 Exceptions</a></H3> - - - <p>The SWIG chicken module has support for exceptions thrown from - C or C++ code to be caught in scheme. - See <a href="Customization.html#Customization_exception">Exception handling with %exception</a> - for more information about declaring exceptions in the interface file. - </p> - - <p>Chicken supports both the <code>SWIG_exception(int code, const char *msg)</code> interface - as well as a <code>SWIG_ThrowException(C_word val)</code> function for throwing exceptions from - inside the %exception blocks. <code>SWIG_exception</code> will throw a list consisting of the code - (as an integer) and the message. Both of these will throw an exception using <code>(abort)</code>, - which can be handled by <code>(handle-exceptions)</code>. See - the Chicken manual on Exceptions - and <a href="http://srfi.schemers.org/srfi-12/srfi-12.html">SFRI-12</a>. Since the exception values are thrown - directly, if <code>(condition-case)</code> is used to catch an exception the exception will come through in the <code>val ()</code> case. - </p> - - <p>The following simple module</p> - -<div class="code"><pre> -%module exception_test - -%inline %{ - void test_throw(int i) throws (int) { - if (i == 1) throw 15; - } -%} -</pre></div> - - <p>could be run with</p> - -<div class="targetlang"><pre> -(handle-exceptions exvar - (if (= exvar 15) - (print "Correct!") - (print "Threw something else " exvar)) - (test-throw 1)) -</pre></div> - - -<H2><a name="Chicken_nn11">23.3 TinyCLOS</a></H2> - - - <p> - The author of TinyCLOS, Gregor Kiczales, describes TinyCLOS as: - "Tiny CLOS is a Scheme implementation of a 'kernelized' CLOS, with a - metaobject protocol. The implementation is even simpler than - the simple CLOS found in 'The Art of the Metaobject Protocol', - weighing in at around 850 lines of code, including (some) - comments and documentation." - </p> - - <p> - Almost all good Scheme books describe how to use metaobjects and - generic procedures to implement an object-oriented Scheme - system. Please consult a Scheme book if you are unfamiliar - with the concept. - </p> - - <p> - - CHICKEN has a modified version of TinyCLOS, which SWIG CHICKEN - uses if the -proxy argument is given. If -proxy is passed, then - the generated example.scm file will contain TinyCLOS class definitions. - A class named Foo is declared as <Foo>, and each member variable - is allocated a slot. Member functions are exported as generic functions. - - <p> - - Primitive symbols and functions (the interface that would be presented if - -proxy was not passed) are hidden and no longer accessible. If the -unhideprimitive - command line argument is passed to SWIG, then the primitive symbols will be - available, but each will be prefixed by the string "primitive:" - - <p> - - The exported symbol names can be controlled with the -closprefix and -useclassprefix arguments. - If -useclassprefix is passed to SWIG, every member function will be generated with the class name - as a prefix. If the -closprefix mymod: argument is passed to SWIG, then the exported functions will - be prefixed by the string "mymod:". If -useclassprefix is passed, -closprefix is ignored. - - </p> - -<H2><a name="Chicken_nn12">23.4 Linkage</a></H2> - - - <p> - Please refer to <em>CHICKEN - A practical and portable Scheme - system - User's manual</em> for detailed help on how to link - object files to create a CHICKEN Scheme program. Briefly, to - link object files, be sure to add <tt>`chicken-config - -extra-libs -libs`</tt> or <tt>`chicken-config -shared - -extra-libs -libs`</tt>to your linker options. Use the - <tt>-shared</tt> option if you want to create a dynamically - loadable module. You might also want to use the much simpler - <tt>csc</tt> or <tt>csc.bat</tt>. - </p> - - <p>Each scheme file that is generated - by SWIG contains <code>(declare (uses <i>modname</i>))</code>. This means that to load the - module from scheme code, the code must include <code>(declare (uses <i>modname</i>))</code>. - </p> - - -<H3><a name="Chicken_nn13">23.4.1 Static binary or shared library linked at compile time</a></H3> - - - <p>We can easily use csc to build a static binary.</p> - -<div class="shell"> -<pre> -$ swig -chicken example.i -$ csc -v example.scm example_impl.c example_wrap.c test_script.scm -o example -$ ./example -</pre> -</div> - -<p>Similar to the above, any number of <tt>module.scm</tt> files could be compiled -into a shared library, and then that shared library linked when compiling the -main application.</p> - -<div class="shell"> -<pre> -$ swig -chicken example.i -$ csc -sv example.scm example_wrap.c example_impl.c -o example.so -</pre> -</div> - -<p>The <tt>example.so</tt> file can then linked with <tt>test_script.scm</tt> when it -is compiled, in which case <tt>test_script.scm</tt> must have <code>(declare (uses example))</code>. -Multiple SWIG modules could have been linked into <tt>example.so</tt> and each -one accessed with a <code>(declare (uses ... ))</code>. -</p> - -<div class="shell"> -<pre> -$ csc -v test_script.scm -lexample -</pre> -</div> - -<p>An alternative is that the test_script.scm can have the code <code>(load-library 'example "example.so")</code>, -in which case the test script does not need to be linked with example.so. The test_script.scm file can then -be run with <tt>csi</tt>. -</p> - -<H3><a name="Chicken_nn14">23.4.2 Building chicken extension libraries</a></H3> - - -<p>Building a shared library like in the above section only works if the library -is linked at compile time with a script containing <code>(declare (uses ...))</code> or is -loaded explicitly with <code>(load-library 'example "example.so")</code>. It is -not the format that CHICKEN expects for extension libraries and eggs. The problem is the -<code>(declare (unit <i>modname</i>))</code> inside the <tt>modname.scm</tt> file. There are -two possible solutions to this.</p> - -<p>First, SWIG accepts a <tt>-nounit</tt> argument, in which case the <code>(declare (unit <i>modname</i>))</code> -is not generated. Then, the <tt>modname.scm</tt> and <tt>modname_wrap.c</tt> files <b>must</b> be compiled into -their own shared library.</p> - -<div class="shell"> -<pre> -$ csc -sv modname.scm modname_wrap.c modname_impl.c -o modname.so -</pre> -</div> - -<p>This library can then be loaded by scheme code with the <code>(require 'modname)</code> function. -See the -Loading-extension-libraries in the eval unit inside the CHICKEN manual for more information.</p> - -<p>Another alternative is to run SWIG normally and create a scheme file that contains <code>(declare (uses <i>modname</i>))</code> -and then compile that file into the shared library as well. For example, inside the <tt>mod_load.scm</tt> file,</p> - -<div class="targetlang"> -<pre> -(declare (uses mod1)) -(declare (uses mod2)) -</pre> -</div> - -<p>Which would then be compiled with</p> - -<div class="shell"> -<pre> -$ swig -chicken mod1.i -$ swig -chicken mod2.i -$ csc -sv mod_load.scm mod1.scm mod2.scm mod1_wrap.c mod2_wrap.c mod1_impl.c mod2_impl.c -o mod.so -</pre> -</div> - -<p>Then the extension library can be loaded with <code>(require 'mod)</code>. As we can see here, -<tt>mod_load.scm</tt> contains the code that gets executed when the module is loaded. All this code -does is load both mod1 and mod2. As we can see, this technique is more useful when you want to -combine a few SWIG modules into one chicken extension library, especially if modules are related by -<code>%import</code></p> - -<p>In either method, the files that are compiled into the shared library could also be -packaged into an egg. The <tt>mod1_wrap.c</tt> and <tt>mod2_wrap.c</tt> files that are created by SWIG -are stand alone and do not need SWIG to be installed to be compiled. Thus the egg could be -distributed and used by anyone, even if SWIG is not installed.</p> - -<p>See the <tt>Examples/chicken/egg</tt> directory in the SWIG source for an example that builds -two eggs, one using the first method and one using the second method.</p> - -<H3><a name="Chicken_nn15">23.4.3 Linking multiple SWIG modules with TinyCLOS</a></H3> - - -<p>Linking together multiple modules that share type information using the <code>%import</code> -directive while also using <tt>-proxy</tt> is more complicated. For example, if <tt>mod2.i</tt> imports <tt>mod1.i</tt>, then the -<tt>mod2.scm</tt> file contains references to symbols declared in <tt>mod1.scm</tt>, -and thus a <code>(declare (uses <i>mod1</i>))</code> or <code>(require '<i>mod1</i>)</code> must be exported -to the top of <tt>mod2.scm</tt>. By default, when SWIG encounters an <code>%import "modname.i"</code> directive, -it exports <code>(declare (uses <i>modname</i>))</code> into the scm file. This works fine unless mod1 was compiled with -the <tt>-nounit</tt> argument or was compiled into an extension library with other modules under a different name.</p> - -<p>One option is to override the automatic generation of <code>(declare (uses mod1))</code> -by passing the <tt>-noclosuses</tt> option to SWIG when compiling <tt>mod2.i</tt>. -SWIG then provides the <code>%insert(closprefix) %{ %}</code> directive. Any scheme code inside that directive is inserted into the -generated .scm file, and if <tt>mod1</tt> was compiled with <tt>-nounit</tt>, the directive should contain <code>(require 'mod1)</code>. -This option allows for mixed loading as well, where some modules are imported with <code>(declare (uses <i>modname</i>))</code> -(which means they were compiled without -nounit) and some are imported with <code>(require 'modname)</code>.</p> - -<p>The other option is to use the second idea in the above section. Compile all the modules normally, without any -<code>%insert(closprefix)</code>, <tt>-nounit</tt>, or <tt>-noclosuses</tt>. Then the modules will import each other correctly -with <code>(declare (uses ...))</code>. -To create an extension library or an egg, just create a <tt>module_load.scm</tt> file that <code>(declare (uses ...))</code> -all the modules.</p> - -<H2><a name="Chicken_nn16">23.5 Typemaps</a></H2> - - - <p> - The Chicken module handles all types via typemaps. This information is - read from <code>Lib/chicken/typemaps.i</code> and - <code>Lib/chicken/chicken.swg</code>. - </p> - -<H2><a name="Chicken_nn17">23.6 Pointers</a></H2> - - - <p> - For pointer types, SWIG uses CHICKEN tagged pointers. - - A tagged pointer is an ordinary CHICKEN pointer with an - extra slot for a void *. With SWIG - CHICKEN, this void * is a pointer to a type-info - structure. So each pointer used as input or output from - the SWIG-generated CHICKEN wrappers will have type - information attached to it. This will let the wrappers - correctly determine which method should be called - according to the object type hierarchy exposed in the SWIG - interface files. - </p> - <p> - To construct a Scheme object from a C pointer, the wrapper code - calls the function - <code>SWIG_NewPointerObj(void *ptr, swig_type_info *type, int owner)</code>, - The function that calls <code>SWIG_NewPointerObj</code> must have a variable declared - <code>C_word *known_space = C_alloc(C_SIZEOF_SWIG_POINTER);</code> - It is ok to call <code>SWIG_NewPointerObj</code> more than once, - just make sure known_space has enough space for all the created pointers. - </p> - <p> - To get the pointer represented by a CHICKEN tagged pointer, the - wrapper code calls the function - <code>SWIG_ConvertPtr(C_word s, void **result, swig_type_info *type, int flags)</code>, - passing a pointer to a struct representing the expected pointer - type. flags is either zero or SWIG_POINTER_DISOWN (see below). - </p> - -<H3><a name="Chicken_collection">23.6.1 Garbage collection</a></H3> - - - <p>If the owner flag passed to <code>SWIG_NewPointerObj</code> is 1, <code>NewPointerObj</code> will add a - finalizer to the type which will call the destructor or delete method of - that type. The destructor and delete functions are no longer exported for - use in scheme code, instead SWIG and chicken manage pointers. - In situations where SWIG knows that a function is returning a type that should - be garbage collected, SWIG will automatically set the owner flag to 1. For other functions, - the <code>%newobject</code> directive must be specified for functions whose return values - should be garbage collected. See - <a href="Customization.html#Customization_ownership">Object ownership and %newobject</a> for more information. - </p> - - <p>In situations where a C or C++ function will assume ownership of a pointer, and thus - chicken should no longer garbage collect it, SWIG provides the <code>DISOWN</code> input typemap. - After applying this typemap (see the <a href="Typemaps.html#Typemaps">Typemaps chapter</a> for more information on how to apply typemaps), - any pointer that gets passed in will no longer be garbage collected. - An object is disowned by passing the <code>SWIG_POINTER_DISOWN</code> flag to <code>SWIG_ConvertPtr</code>. - <b>Warning:</b> Since the lifetime of the object is now controlled by the underlying code, the object might - get deleted while the scheme code still holds a pointer to it. Further use of this pointer - can lead to a crash. - </p> - - <p>Adding a finalizer function from C code was added to chicken in the 1.89 release, so garbage collection - does not work for chicken versions below 1.89. If you would like the SWIG generated code to work with - chicken 1.40 to 1.89, pass the <code>-nocollection</code> argument to SWIG. This will not export code - inside the _wrap.c file to register finalizers, and will then export destructor functions which - must be called manually. - </p> - -<H2><a name="Chicken_nn18">23.7 Unsupported features and known problems</a></H2> - - - <ul> - <li>No director support.</li> - <li>No support for c++ standard types like std::vector.</li> - <li>The TinyCLOS wrappers for overloaded functions will not work correctly when using - <a href="SWIGPlus.html#SWIGPlus_default_args">%feature(compactdefaultargs)</a>.</li> - </ul> - -<H3><a name="Chicken_nn19">23.7.1 TinyCLOS problems with Chicken version <= 1.92</a></H3> - - - <p>In Chicken versions equal to or below 1.92, TinyCLOS has a limitation such that generic methods do not properly work on methods - with different number of specializers: TinyCLOS assumes that every method added to a generic function - will have the same number of specializers. SWIG generates functions with different lengths of specializers - when C/C++ functions are overloaded. For example, the code</p> - -<div class="code"> -<pre> -class Foo {}; -int foo(int a, Foo *b); -int foo(int a); -</pre></div> - -<p>will produce scheme code</p> - -<div class="targetlang"> -<pre> -(define-method (foo (arg0 <top>) (arg1 <Foo>)) (<i>call primitive function</i>)) -(define-method (foo (arg0 <top>)) (<i>call primitive function</i>)) -</pre></div> - -<p>Using unpatched TinyCLOS, the second <code>(define-method)</code> will replace the first one, -so calling <code>(foo 3 f)</code> will produce an error.</p> - -<p>There are three solutions to this. The easist is to upgrade to the latest Chicken version. Otherwise, the -file <tt>Lib/chicken/tinyclos-multi-generic.patch</tt> in the SWIG source contains a patch against -tinyclos.scm inside the 1.92 chicken source to add support into TinyCLOS for multi-argument generics. (This patch was accepted into Chicken) -This requires chicken to be rebuilt and custom install of chicken. An alternative is the <tt>Lib/chicken/multi-generic.scm</tt> -file in the SWIG source. This file can be loaded after TinyCLOS is loaded, and it will override some functions -inside TinyCLOS to correctly support multi-argument generics. Please see the comments at the top of both files for more information.</p> - - </body> -</html> |