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[lua] added %luacode feature, documentation & examples

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git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@10312 626c5289-ae23-0410-ae9c-e8d60b6d4f22
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Mark Gossage 2008-03-17 08:50:59 +00:00
commit e543cd9040
12 changed files with 279 additions and 25 deletions
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Doc/Manual/Lua.html
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@ -35,12 +35,13 @@
<li><a href="#Lua_nn21">C++ Smart Pointers</a>
<li><a href="#Lua_nn22">C++ exceptions</a>
<li><a href="#Lua_nn23">Writing your own custom wrappers</a>
<li><a href="#Lua_nn24">Adding additional Lua code</a>
</ul>
<li><a href="#Lua_nn24">Details on the Lua binding</a>
<li><a href="#Lua_nn25">Details on the Lua binding</a>
<ul>
<li><a href="#Lua_nn25">Binding global data into the module.</a>
<li><a href="#Lua_nn26">Userdata and Metatables</a>
<li><a href="#Lua_nn27">Memory management</a>
<li><a href="#Lua_nn26">Binding global data into the module.</a>
<li><a href="#Lua_nn27">Userdata and Metatables</a>
<li><a href="#Lua_nn28">Memory management</a>
</ul>
</ul>
</div>
@ -1089,7 +1090,43 @@ int native_function(lua_State*L) // my native code
The <tt>%native</tt> directive in the above example, tells SWIG that there is a function <tt>int native_function(lua_State*L);</tt> which is to be added into the module under the name '<tt>my_func</tt>'. SWIG will not add any wrappering for this function, beyond adding it into the function table. How you write your code is entirely up to you.
</p>
<H2><a name="Lua_nn24"></a>22.4 Details on the Lua binding</H2>
<H3><a name="Lua_nn24"></a>22.3.17 Adding additional Lua code</H3>
<p>
As well as adding additional C/C++ code, its also possible to add your own Lua code to the module as well.
This code is executed once all other initialisation, including the %init code has been called.
</p>
<p>
The directive <tt>%luacode</tt> adds code into the module which is executed upon loading. Normally you would
use this to add your own functions to the module. Though you could easily perform other tasks.
</p>
<div class="code"><pre>%module example;
%luacode {
function example.greet()
print "hello world"
end
print "Module loaded ok"
}
...
%}
</pre></div>
<p>
Notice that the code is not part of the module table. Therefore any references to the module must have the
module name added.
</p>
<p>
Should there be an error in the Lua code, this will <em>not</em> stop loading of the module.
The default behaviour of SWIG is to print a error message to stderr and then continue.
It is possible to change this behaviour by using a <tt>#define SWIG_DOSTRING_FAIL(STR)</tt> to
define a different behaviour should the code fail.
</p>
<p>
Good uses for this feature is adding of new code, or writing helper functions to simplify some of the code.
See Examples/lua/arrays, for an example of this code.
</p>
<H2><a name="Lua_nn25"></a>22.4 Details on the Lua binding</H2>
<p>
@ -1100,7 +1137,7 @@ The <tt>%native</tt> directive in the above example, tells SWIG that there is a
</i>
</p>
<H3><a name="Lua_nn25"></a>22.4.1 Binding global data into the module.</H3>
<H3><a name="Lua_nn26"></a>22.4.1 Binding global data into the module.</H3>
<p>
@ -1160,7 +1197,7 @@ end
<p>
That way when you call '<tt>a=example.Foo</tt>', the interpreter looks at the table 'example' sees that there is no field 'Foo' and calls __index. This will in turn check in '.get' table and find the existence of 'Foo' and then return the value of the C function call 'Foo_get()'. Similarly for the code '<tt>example.Foo=10</tt>', the interpreter will check the table, then call the __newindex which will then check the '.set' table and call the C function 'Foo_set(10)'.
</p>
<H3><a name="Lua_nn26"></a>22.4.2 Userdata and Metatables</H3>
<H3><a name="Lua_nn27"></a>22.4.2 Userdata and Metatables</H3>
<p>
@ -1240,7 +1277,7 @@ Note: Both the opaque structures (like the FILE*) and normal wrappered classes/s
<p>
Note: Operator overloads are basically done in the same way, by adding functions such as '__add' &amp; '__call' to the classes metatable. The current implementation is a bit rough as it will add any member function beginning with '__' into the metatable too, assuming its an operator overload.
</p>
<H3><a name="Lua_nn27"></a>22.4.3 Memory management</H3>
<H3><a name="Lua_nn28"></a>22.4.3 Memory management</H3>
<p>