mirror of
https://github.com/Llewellynvdm/conky.git
synced 2024-11-18 11:05:18 +00:00
1957 lines
71 KiB
HTML
1957 lines
71 KiB
HTML
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
|
||
|
|
<HTML>
|
||
|
|
<HEAD>
|
||
|
|
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
|
||
|
|
<META NAME="GENERATOR" CONTENT="Textpad">
|
||
|
|
<META NAME="Author" CONTENT="Waldemar Celes, Ariel Manzur">
|
||
|
|
<TITLE>tolua++ reference manual</TITLE>
|
||
|
|
</HEAD>
|
||
|
|
<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#0000EE" VLINK="#551A8B" ALINK="#FF0000">
|
||
|
|
|
||
|
|
<H1>
|
||
|
|
<IMG SRC="toluapp.gif">tolua++ - Reference Manual</I></H1>
|
||
|
|
by Waldemar Celes, Ariel Manzur.
|
||
|
|
|
||
|
|
<H1>
|
||
|
|
|
||
|
|
</h1>
|
||
|
|
|
||
|
|
<HR ALIGN=LEFT SIZE=5 WIDTH="100%">
|
||
|
|
|
||
|
|
<b>tolua++</b> is an extended version of <a href="http://www.tecgraf.puc-rio.br/~celes/tolua/">tolua</a>, a tool to integrate
|
||
|
|
C/C++ code with <A HREF="http://www.tecgraf.puc-rio.br/lua">Lua</A>. <b>tolua++</b>
|
||
|
|
includes new features oriented to c++ such as:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<ul>
|
||
|
|
<li> Support for <b>std::string</b> as a <a href="#basics">basic type</a> (this can be turned off by a command line option).</li>
|
||
|
|
<li> Support for <a href="#templates">class templates</a></li>
|
||
|
|
</ul>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
As well as other features and bugfixes.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
|
||
|
|
<B>tolua</B> is a tool that greatly simplifies the integration of C/C++
|
||
|
|
code with <A HREF="http://www.tecgraf.puc-rio.br/lua">Lua</A>. Based on
|
||
|
|
a <I>cleaned</I> <I>header file</I> (or extracts from real header files),
|
||
|
|
<B>tolua</B> automatically generates
|
||
|
|
the binding code to access C/C++ features from Lua. Using Lua API and tag
|
||
|
|
method facilities, <B>tolua </B>maps C/C++ constants, external variables,
|
||
|
|
functions, classes, and methods to Lua.
|
||
|
|
<P>This manual is for <B>tolua++</B> version 1.0 and is implemented upon Lua
|
||
|
|
5.0 and based on <b>tolua 5.0</b>. See <A HREF="#changes-v30">Compatibility</A>
|
||
|
|
for details on switching from older versions.
|
||
|
|
<P>The sections below describe how to use <B>tolua</B>. Please <A HREF="mailto:tolua@codenix.com">contact us</A>
|
||
|
|
with bug reports, suggestions, and comments.
|
||
|
|
<UL>
|
||
|
|
<LI>
|
||
|
|
Shortcuts:</LI>
|
||
|
|
|
||
|
|
<UL>
|
||
|
|
<LI>
|
||
|
|
<A HREF="#introduction">How <B>tolua</B> works</A></LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#using">How to use <B>tolua</B></A></LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#basics">Basic Concepts</A></LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#constants">Binding constants</A></LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#variables">Binding external variables</A></LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#functions">Binding functions</A></LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#structs">Binding struct fields</A></LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#classes">Binding classes and methods</A></LI>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
<a href="#propeties">Binding properties</a></li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
<a href="#templates">Class Templates</a></li>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#modules">Module definition</A></LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#renaming">Renaming constants, variables and functions</A></LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#additional">Storing additional fields</A></LI>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
<a href="#additional_features">Additional features</a></li>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#utilities">Exported utility functions</A></LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#embedded">Embedded Lua code</A></LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<a HREF="#customizing">Customizing tolua++</a></li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
<a href="#compatibility">Compatibility with older versions</a></li>
|
||
|
|
|
||
|
|
<li>
|
||
|
|
<A HREF="#changes-v30">Changes since v3 *</A></li>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#changes-v2">Changes since v2.*</A></LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#changes-v1">Changes since v1.*</A></LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#credits">Credits</A></LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
<A HREF="#availability">Availability</A></LI>
|
||
|
|
</UL>
|
||
|
|
</UL>
|
||
|
|
|
||
|
|
<HR WIDTH="100%">
|
||
|
|
<H3>
|
||
|
|
<A NAME="introduction"></A>How tolua works</H3>
|
||
|
|
To use <B>tolua</B>, we create a <I>package file</I>, a C/C++ cleaned header
|
||
|
|
file<I>,</I> listing the constants, variables, functions, classes, and
|
||
|
|
methods we want to export to the Lua environment. Then <B>tolua</B> parses
|
||
|
|
this file and creates a C/C++ file that automatically binds the C/C++ code
|
||
|
|
to Lua. If we link the created file with our application, the specified
|
||
|
|
C/C++ code can be accessed from Lua.<br>
|
||
|
|
A package file can also include regular header files, other package files,
|
||
|
|
or lua files.<br>
|
||
|
|
<P>Let's start with some examples. If we specify as input the following
|
||
|
|
C-like header file to <B>tolua</B>:
|
||
|
|
<PRE>#define FALSE 0
|
||
|
|
#define TRUE 1
|
||
|
|
|
||
|
|
enum {
|
||
|
|
POINT = 100,
|
||
|
|
LINE,
|
||
|
|
POLYGON
|
||
|
|
}</PRE>
|
||
|
|
|
||
|
|
<PRE>Object* createObejct (int type);
|
||
|
|
void drawObject (Object* obj, double red, double green, double blue);
|
||
|
|
int isSelected (Object* obj);</PRE>
|
||
|
|
A C file that binds such a code to Lua is automatically generated. Therefore,
|
||
|
|
in Lua code, we can access the C code, writing, for instance:
|
||
|
|
<PRE>...
|
||
|
|
myLine = createObject(LINE)
|
||
|
|
...
|
||
|
|
if isSelected(myLine) == TRUE then
|
||
|
|
drawObject(myLine, 1.0, 0.0, 0.0);
|
||
|
|
else
|
||
|
|
drawObject(myLine, 1.0, 1.0, 1.0);
|
||
|
|
end
|
||
|
|
...</PRE>
|
||
|
|
Also, consider a C++-like header file:
|
||
|
|
<PRE>#define FALSE 0
|
||
|
|
#define TRUE 1</PRE>
|
||
|
|
|
||
|
|
<PRE>class Shape
|
||
|
|
{
|
||
|
|
void draw (void);
|
||
|
|
void draw (double red, double green, double blue);
|
||
|
|
int isSelected (void);
|
||
|
|
};</PRE>
|
||
|
|
|
||
|
|
<PRE>class Line : public Shape
|
||
|
|
{
|
||
|
|
Line (double x1, double y1, double x2, double y2);
|
||
|
|
~Line (void);
|
||
|
|
};</PRE>
|
||
|
|
If this file is used as input to <B>tolua</B>, a C++ file is automatically
|
||
|
|
generated proving access to such a code from Lua. Therefore, it would be
|
||
|
|
valid to write Lua statements like:
|
||
|
|
<PRE>...
|
||
|
|
myLine = Line:new (0,0,1,1)
|
||
|
|
...
|
||
|
|
if myLine:isSelected() == TRUE then
|
||
|
|
myLine:draw(1.0,0.0,0.0)
|
||
|
|
else
|
||
|
|
myLine:draw()
|
||
|
|
end
|
||
|
|
...
|
||
|
|
myLine:delete()
|
||
|
|
...</PRE>
|
||
|
|
The package file (usually with extension <TT>.pkg</TT>) passed to <B>tolua</B>
|
||
|
|
is not the real C/C++ header file, but a <I>cleaned </I>version of it.
|
||
|
|
<B>tolua</B>
|
||
|
|
does not implement a complete parse to interpret C/C++ code, but it understands
|
||
|
|
a few declarations that are used to describe the features that are to be
|
||
|
|
exported to Lua. Regular header files can be included into packages files; <b>tolua</b>
|
||
|
|
will extract the code specified by the user to parse from the header (see <a href="#basics">Basic Concepts</a>).
|
||
|
|
<H3>
|
||
|
|
<A NAME="using"></A>How to use toLua</H3>
|
||
|
|
<B>tolua </B>is composed by two pieces of code: an executable and a library.
|
||
|
|
The executable represents the parser that reads a package file and output
|
||
|
|
a C/C++ code that implements the binding to access the C/C++ features from
|
||
|
|
Lua. If the package file is a C++ like code (i.e., includes class definitions),
|
||
|
|
a C++ code is generated. If the cleaned header file is a C like code (i.e.,
|
||
|
|
without classes), a C code is generated. <B>tolua</B> accepts a set of
|
||
|
|
options. Running <TT>"tolua -h"</TT> displays the current accepted options.
|
||
|
|
For instance, to parse a file called <TT>myfile.pkg
|
||
|
|
</TT>generating the
|
||
|
|
binding code in <TT>myfile.c</TT>, we do:
|
||
|
|
<P><TT>tolua -o myfile.c myfile.pkg</TT>
|
||
|
|
<P>The generated code must be compiled and linked with the application
|
||
|
|
to provide the desired access from Lua. Each parsed file represents a package
|
||
|
|
being exported to Lua. By default, the package name is the input file root
|
||
|
|
name (<TT>myfile </TT>in the example). The user can specify a different
|
||
|
|
name for the package:
|
||
|
|
<P><TT>tolua -n pkgname -o myfile.c myfile.pkg</TT>
|
||
|
|
<P>The package should also be explicitly initialized. To initialize the
|
||
|
|
package from our C/C++ code, we must declare and call the initialization
|
||
|
|
function. The initialization function is defined as
|
||
|
|
<P><TT>int tolua_<I>pkgname</I>_open (lua_State*);</TT>
|
||
|
|
<P>where <I><TT>pkgname </TT></I>represents the name of the package being
|
||
|
|
bound. If we are using C++, we can opt for automatic initialization:
|
||
|
|
<P><TT>tolua -a -n pkgname -o myfile.c myfile.pkg</TT>
|
||
|
|
<P>In that case, the initialization function is automatically called. However,
|
||
|
|
if we are planning to use multiple Lua states, automatic initialization
|
||
|
|
does not work, because the order static variables are initialized in C++
|
||
|
|
is not defined.
|
||
|
|
<!--
|
||
|
|
<P>The current <B>tolua</B> version also exports a closing function, which
|
||
|
|
can be called to unbind the package.
|
||
|
|
<P><TT>void tolua_<I>pkgname</I>_close (void);</TT>
|
||
|
|
-->
|
||
|
|
<P>Optionally, the prototype of the <TT>open</TT> function
|
||
|
|
can be outputted to a header file, which name is given by the <TT>-H</TT>
|
||
|
|
option.
|
||
|
|
<P>The binding code generated by <B>tolua </B>uses a set of functions defined
|
||
|
|
in the <B>tolua </B>library. Thus, this library also has to be linked with
|
||
|
|
the application. The file <TT>tolua.h</TT> is also necessary to compile
|
||
|
|
the generated code.
|
||
|
|
<P>An application can use tolua object oriented framework (see <A HREF="#utilities">exported
|
||
|
|
utility functions</A>) without binding any package. In that case, the application
|
||
|
|
must call <B>tolua </B>initialization function (this function is called
|
||
|
|
by any package file initialization function):
|
||
|
|
<P><TT>int tolua_open (void);</TT>
|
||
|
|
<!--
|
||
|
|
<P>If multiple Lua states are to be used, after setting a Lua state, we
|
||
|
|
need to call a function to restore <B>tolua </B>internal state:
|
||
|
|
<P><TT>void tolua_restorestate (void);</TT>
|
||
|
|
-->
|
||
|
|
<H3>
|
||
|
|
<A NAME="basics"></A>Basic Concepts</H3>
|
||
|
|
The first step in using <B>tolua</B> is to create the package file. Starting
|
||
|
|
with the real header files, we clean them by declaring the features we
|
||
|
|
want to access from Lua in a format that <B>tolua</B> can understand. The
|
||
|
|
format <B>tolua</B> understands is simple C/C++ declarations as described
|
||
|
|
below.
|
||
|
|
|
||
|
|
<H4>Including files</h4>
|
||
|
|
|
||
|
|
A package file may include other package file. The general format
|
||
|
|
to do that is:
|
||
|
|
<p>
|
||
|
|
<TT>$pfile "<I>include_file</I>"</TT>
|
||
|
|
<p>
|
||
|
|
A package file may also include regular C/C++ header files, using the <TT>hfile</TT>
|
||
|
|
or <TT>cfile</tt> directive:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<tt>$cfile "example.h"</tt>
|
||
|
|
<p>
|
||
|
|
In which case, <b>tolua</b> will extract the code enclosed between <tt>tolua_begin</tt>
|
||
|
|
and <tt>tolua_end</tt>, or or <tt>tolua_export</tt> for a single line. Consider this C++ header as example:
|
||
|
|
|
||
|
|
<PRE>
|
||
|
|
|
||
|
|
#ifndef EXAMPLE_H
|
||
|
|
#define EXAMPLE_H
|
||
|
|
|
||
|
|
class Example { // tolua_export
|
||
|
|
|
||
|
|
private:
|
||
|
|
|
||
|
|
string name;
|
||
|
|
int number;
|
||
|
|
|
||
|
|
public:
|
||
|
|
|
||
|
|
void set_number(int number);
|
||
|
|
|
||
|
|
//tolua_begin
|
||
|
|
|
||
|
|
string get_name();
|
||
|
|
int get_number();
|
||
|
|
};
|
||
|
|
// tolua_end
|
||
|
|
|
||
|
|
#endif
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
In this case, the code that's not supported by <b>tolua</b> (the
|
||
|
|
private part of the class), along with the function <tt>set_number</tt>
|
||
|
|
is left outside of the package that includes this header.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
Finally, lua files can be included on a package file, using <tt>$lfile</tt>:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<tt>$lfile "example.lua"</tt>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<b>New on tolua++</b>: an extra way to include source files is available since
|
||
|
|
version 1.0.4 of <b>tolua++</b>, using <tt>ifile</tt>:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<tt>$ifile "filename"</tt>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<tt>ifile</tt> also takes extra optional parameters after the filename, for example:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<tt>
|
||
|
|
$ifile "widget.h", GUI<br>
|
||
|
|
$ifile "vector.h", math, 3d
|
||
|
|
</tt>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<tt>ifile</tt>'s default behaviour is to include the whole file, untouched. However,
|
||
|
|
the contents of the file and the extra parameters are put through the <tt>include_file_hook</tt>
|
||
|
|
function before being included into the package (see <a href="#customizing">Customizing tolua++</a>
|
||
|
|
for more details).
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<H4>
|
||
|
|
Basic types</H4>
|
||
|
|
<B>tolua </B>automatically maps C/C++ basic types to Lua basic types. Thus,
|
||
|
|
<TT>char</TT>,
|
||
|
|
<TT>int</TT>,
|
||
|
|
<TT>float</TT>, and <TT>double </TT>are mapped to the Lua type <TT>number</TT>;<TT>
|
||
|
|
char*</TT> is mapped to <TT>string</TT>; and<TT> void*</TT> is mapped to
|
||
|
|
<TT>userdata</TT>. Types may be preceded by modifiers (<TT>unsigned</TT>,
|
||
|
|
<TT>static</TT>, <TT>short</TT>, <TT>const</TT>, etc.); however, be aware
|
||
|
|
that <B>tolua </B>ignores the modifier <TT>const</TT> if applied to basic
|
||
|
|
types. Thus, if we pass a constant basic type to Lua and then pass it back
|
||
|
|
to C/C++ code where a non constant is expected, the constant to non constant
|
||
|
|
conversion will be silently done.
|
||
|
|
<P>Functions in C/C++ can also manipulate Lua objects explicitly. Thus
|
||
|
|
<TT>lua_Object</TT>
|
||
|
|
is also considered a basic type. In this case, any Lua value matches it.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<b>New on tolua++</b>: The C++ type <tt>string</tt> is also considered a basic type, and is passed as
|
||
|
|
a value to lua (using the <tt>c_str()</tt> method). This feature can be turned off
|
||
|
|
with the command line option <tt>-S</tt>.
|
||
|
|
|
||
|
|
<H4>
|
||
|
|
User defined types</H4>
|
||
|
|
All other types that appear in the package file being processed are considered
|
||
|
|
user defined types. These are mapped to tagged userdata type in Lua. Lua
|
||
|
|
can only store pointers to user defined types; although, <B>tolua
|
||
|
|
</B>automatically
|
||
|
|
makes the necessary arrangement to deal with references and values. For
|
||
|
|
instance, if a function or method returns a value of user defined type,
|
||
|
|
<B>tolua
|
||
|
|
</B>allocates
|
||
|
|
a clone object when returning it to Lua and sets the garbage collection
|
||
|
|
tag method to automatically free the allocated object when no longer in
|
||
|
|
use by Lua.
|
||
|
|
<P>For user defined types, <tt>const</tt>ness is preserved. Thus passing a non constant
|
||
|
|
user defined type to a function that expects constant type generates an
|
||
|
|
type mismatching error.
|
||
|
|
<H4>
|
||
|
|
<TT>NULL </TT>and <TT>nil</TT></H4>
|
||
|
|
C/C++ <TT>NULL</TT> or <TT>0 </TT>pointers are mapped to Lua
|
||
|
|
<TT>nil </TT>type;
|
||
|
|
conversely, <TT>nil </TT>may be specified wherever a C/C++ pointer is expected.
|
||
|
|
This is valid for any type: <TT>char*</TT>,
|
||
|
|
<TT>void*</TT>, and pointers
|
||
|
|
to user defined types.
|
||
|
|
<H4>
|
||
|
|
Typedefs</H4>
|
||
|
|
<B>tolua </B>also accepts simple typedef<I>'s </I>inside the package files.
|
||
|
|
Any occurrence of a type after its definition is mapped by <B>tolua
|
||
|
|
</B>to
|
||
|
|
the base type. They are useful because several packages redefine the basic
|
||
|
|
C/C++ types to their own types. For instance, one can define the type <TT>real
|
||
|
|
</TT>to
|
||
|
|
represent a <TT>double</TT>. In that case, <TT>real
|
||
|
|
</TT>can be used to
|
||
|
|
specify the variable types inside the package file interpreted by <B>tolua</B>,
|
||
|
|
but only if we include the following definition before any use of the type
|
||
|
|
<TT>real</TT>.
|
||
|
|
<P><TT>typedef double real;</TT>
|
||
|
|
<P>Otherwise, <TT>real </TT>would be interpreted as a user defined type
|
||
|
|
and would not be mapped to Lua numbers.
|
||
|
|
<H4>
|
||
|
|
Including real header files</H4>
|
||
|
|
In the package file, we must specify which are the real header files that
|
||
|
|
should be included so that the generated code can access the constants,
|
||
|
|
variables, functions, and classes we are binding. Any line in the package
|
||
|
|
file beginning with a <B>$ </B>(except $[hclp]file, $[ , and $] lines) is
|
||
|
|
inserted into the generated binding C/C++ code without any change, but the
|
||
|
|
elimination of the <B>$</B> itself. We use this feature to include the
|
||
|
|
real header files. So, our package files will usually start with a set
|
||
|
|
of <B>$</B> beginning lines specifying the files that must be included,
|
||
|
|
that is, the files the package file is based on.
|
||
|
|
<PRE>/* specify the files to be included */</PRE>
|
||
|
|
|
||
|
|
<PRE>$#include "header1.h" // include first header
|
||
|
|
$#include "header2.h" // include second header</PRE>
|
||
|
|
As illustrated, <B>tolua </B>also accepts comments, using C or C++ convention,
|
||
|
|
inside the package file. Nested C-like comments can also be used.
|
||
|
|
<p>
|
||
|
|
Also note that files included with <tt>$cfile</tt> or <tt>$hfile</tt> don't
|
||
|
|
need to be included using this method, this is done automatically by <b>tolua</b>.
|
||
|
|
|
||
|
|
<P>In the following sections, we describe how to specify the C/C++ code
|
||
|
|
we want to bind to Lua. The formats are simplified valid C/C++ statements.
|
||
|
|
|
||
|
|
<H3>
|
||
|
|
<A NAME="constants"></A>Binding constants</H3>
|
||
|
|
To bind constants, <B>tolua </B>accepts both define's and enum's. For define's
|
||
|
|
the general format is:
|
||
|
|
<PRE><B>#define</B> <I>NAME </I>[ <I>VALUE </I>]</PRE>
|
||
|
|
The value, as showed above, is optional. If such a code is inserted inside
|
||
|
|
the file being processed, <B>tolua </B>generates a code that allows the
|
||
|
|
use of <I><TT>NAME </TT></I>as a Lua global variable that has the corresponding
|
||
|
|
C/C++ constant value. Only numeric constants are accepted.
|
||
|
|
<p>
|
||
|
|
<b>New on tolua++</b>: All other preprocessor directives are ignored.
|
||
|
|
<P>For enum's, the general format is:
|
||
|
|
<PRE><B>enum {
|
||
|
|
</B> <I><TT>NAME1 </TT></I>[ <B>=</B> <I>VALUE1 </I>] <B>,
|
||
|
|
</B> <I>NAM</I>E2 [ <B>=</B> <I>VALUE2 </I>] <B>,
|
||
|
|
</B> ...
|
||
|
|
<I>NAMEn </I>[ <B>=</B> <I>VALUEn </I>]
|
||
|
|
<B>};</B></PRE>
|
||
|
|
Similarly, <B>tolua</B> creates a set of global variables, named <I><TT>NAMEi</TT></I>,
|
||
|
|
with their corresponding values.
|
||
|
|
<H3>
|
||
|
|
<A NAME="variables"></A>Binding external variables</H3>
|
||
|
|
Global extern variables can also be exported. In the cleaned header file
|
||
|
|
they are specified as:
|
||
|
|
<PRE><TT>[</TT><B>extern</B><TT>]</TT><B> </B><I>type var</I><B>;</B></PRE>
|
||
|
|
<B>tolua</B> binds such declarations to Lua global variables. Thus, in
|
||
|
|
Lua, we can access the C/C++ variable naturally. If the variable is non
|
||
|
|
constant, we can also assign the variable a new value from Lua. Global
|
||
|
|
variables that represent arrays of value can also be bound to Lua. Arrays
|
||
|
|
can be of any type. The corresponding Lua objects for arrays are Lua tables
|
||
|
|
indexed with numeric values; however, be aware that index 1 in Lua is mapped
|
||
|
|
to index 0 in an C/C++ array. Arrays must be pre dimensioned. For instance:
|
||
|
|
<P><TT>double v[10];</TT>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
<b>New on tolua++</b>: External variables can use the <tt>tolua_readonly</tt> modifier (see <a href="#additional_features">Additional Features</a>)
|
||
|
|
|
||
|
|
<H3>
|
||
|
|
<A NAME="functions"></A>Binding functions</H3>
|
||
|
|
Functions are also specified as conventional C/C++ declarations:
|
||
|
|
<PRE><I>type funcname </I><B>(</B><I>type1 par1</I>[<B>,</B> <I>type2 <TT>par2</TT></I>[<B>,.</B>..<I>typeN parN</I>]]<B>);</B></PRE>
|
||
|
|
The returned type can be <TT>void</TT>, meaning no value is returned. A
|
||
|
|
function can also have no parameter. In that case, <TT>void </TT>may be
|
||
|
|
specified in the place of the list of parameters. The parameter types must
|
||
|
|
follow the rules already posted. <B>tolua </B>creates a Lua function binding
|
||
|
|
the C/C++ function. When calling a function from Lua, the parameter types
|
||
|
|
must match the corresponding C/C++ types, otherwise, <B>tolua
|
||
|
|
</B>generates
|
||
|
|
an error and reports which parameter is wrongly specified. If a parameter
|
||
|
|
name is omitted, <B>tolua </B>names it automatically, but its type should
|
||
|
|
be a basic type or user type previously used.
|
||
|
|
<H4>
|
||
|
|
Arrays</H4>
|
||
|
|
<B>tolua </B>also deals with function or method parameters that represent
|
||
|
|
arrays of values. The nice thing about arrays is that the corresponding
|
||
|
|
Lua tables have their values updated if the C/C++ function changes the
|
||
|
|
array contents.
|
||
|
|
<P>The arrays must be pre dimensioned. For instance:
|
||
|
|
<P><TT>void func (double a[3]);</TT>
|
||
|
|
<P>is a valid function declaration for <B>tolua</B> and calling this function
|
||
|
|
from Lua would be done by, for instance:
|
||
|
|
<P><TT>p = {1.0,1.5,8.6}</TT>
|
||
|
|
<BR><TT>func (p)</TT>
|
||
|
|
<P>The array dimension need not be a constant expression; the dimension
|
||
|
|
can also be specified by any expression that can be evaluated in run time.
|
||
|
|
For instance:
|
||
|
|
<P><TT>void func (int n, int m, double image[n*m]);</TT>
|
||
|
|
<P>is also valid since the expression <TT>n*m</TT> is valid in the binding
|
||
|
|
function scope. However, be aware that <B>tolua </B>uses dynamic allocation
|
||
|
|
for binding this function, what can degrade the performance.
|
||
|
|
<P>Despite the dimension specification, it is important to know that all
|
||
|
|
arrays passed to the actual C/C++ function are in the local scope of the
|
||
|
|
binding function. So, if the C/C++ function being called needs to hold
|
||
|
|
the array pointer for later use, the binding code will <I>not </I>work
|
||
|
|
properly.
|
||
|
|
<H4>
|
||
|
|
Overloaded functions</H4>
|
||
|
|
Overloaded functions are accepted. Remember that the distinction between
|
||
|
|
two functions with the same name is made based on the parameter types that
|
||
|
|
are mapped to Lua. So, although
|
||
|
|
<P><TT>void func (int a);</TT>
|
||
|
|
<BR><TT>void func (double a);</TT>
|
||
|
|
<P>represent two different functions in C++, they are the same function
|
||
|
|
for <B>tolua</B>, because both <TT>int </TT>and <TT>double </TT>are mapped
|
||
|
|
to the same Lua type: <TT>number</TT>.
|
||
|
|
<P>Another tricky situation occurs when expecting pointers. Suppose:
|
||
|
|
<PRE>void func (char* s);
|
||
|
|
void func (void* p);
|
||
|
|
void func (Object1* ptr);
|
||
|
|
void func (Object2* prt);</PRE>
|
||
|
|
Although these four functions represent different functions in C++, a Lua
|
||
|
|
statement like:
|
||
|
|
<PRE>func(nil)</PRE>
|
||
|
|
matches all of them.
|
||
|
|
<P>It is important to know that <B>tolua </B>decides which function will
|
||
|
|
be called in run-time, trying to match each provided function. <B>tolua
|
||
|
|
</B>first
|
||
|
|
tries to call the last specified function; if it fails, <B>tolua
|
||
|
|
</B>then
|
||
|
|
tries the previous one. This process is repeated until one function matches
|
||
|
|
the calling code or the first function is reached. For that reason, the
|
||
|
|
mismatching error message, when it occurs, is based on the first function
|
||
|
|
specification. When performance is important, we can specify the most used
|
||
|
|
function as the last one, because it will be tried first.
|
||
|
|
<P><B>tolua</B> allows the use of overloaded functions in C, see <A HREF="#renaming">Renaming
|
||
|
|
</A>for
|
||
|
|
details.
|
||
|
|
<H4>
|
||
|
|
Default parameter values</H4>
|
||
|
|
The last function parameters can have associated default values. In that
|
||
|
|
case, if the function is called with fewer parameters, the default values
|
||
|
|
are assumed. The format to specify the default values is the same as the
|
||
|
|
one used in C++ code:
|
||
|
|
<P><TT><I>type funcname </I><B>(</B><I>...</I><B>,</B><I> typeN-1 parN-1
|
||
|
|
[= valueN-1]<B>,</B> typeN parN [= valueN]</I><B>);</B></TT>
|
||
|
|
<P><B>toLua </B>implements this feature without using any C++ mechanism;
|
||
|
|
so, it can be used also to bind C functions.
|
||
|
|
<P>We can also specify default values for the elements of an array (there
|
||
|
|
is no way to specify a default value for the array itself, though). For
|
||
|
|
instance:
|
||
|
|
<P><TT>void func (int a[5]=0);</TT>
|
||
|
|
<P>sets the default element values to zero, thus the function can be called
|
||
|
|
from Lua with an uninitialized table.
|
||
|
|
<P>For Lua object types (<TT>lua_Object</TT>), <B>tolua </B>defines a constant
|
||
|
|
that can be used to specify <TT>nil </TT>as default value:
|
||
|
|
<P><TT>void func (lua_Object lo = TOLUA_NIL);</TT>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<b>New on tolua++</b>: C++ class constructors are valid
|
||
|
|
as default parameters. For example:
|
||
|
|
<p>
|
||
|
|
<tt>void set_color(const Color& color = Color(0,0,0));</tt>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<H4>
|
||
|
|
Multiple returned values</H4>
|
||
|
|
In Lua, a function may return any number of values. <B>tolua </B>uses this
|
||
|
|
feature to simulate values passed by reference. If a function parameter
|
||
|
|
is specified as a pointer to or reference of a basic type or a pointer
|
||
|
|
to or reference of a pointer to an user defined type, <B>tolua </B>accepts
|
||
|
|
the corresponding type as input and returns, besides the conventional function
|
||
|
|
returned value, if any, the updated parameter value.
|
||
|
|
<P>For instance, consider a C function that swaps two values:
|
||
|
|
<P><TT>void swap (double* x, double* y);</TT>
|
||
|
|
<P>or
|
||
|
|
<P><TT>void swap (double& x, double& y);</TT>
|
||
|
|
<P>If such a function is declared in the package file, <B>tolua </B>binds
|
||
|
|
it as a function receiving two numbers as input and returning two numbers.
|
||
|
|
So, a valid Lua code would be:
|
||
|
|
<P><TT>x,y = swap(x,y)</TT>
|
||
|
|
<P>If the input values are not used, the use of default parameter value
|
||
|
|
allows calling the function from Lua without specifying them:
|
||
|
|
<P><TT>void getBox (double* xmin=0, double* xmax=0, double* ymin=0, double*
|
||
|
|
ymax=0);</TT>
|
||
|
|
<P>In Lua:
|
||
|
|
<P><TT>xmin, xmax, ymin, ymax = getBox()</TT>
|
||
|
|
<P>With user defined types, we would have for instance:
|
||
|
|
<P><TT>void update (Point** p);</TT>
|
||
|
|
<P>or
|
||
|
|
<P><TT>void update (Point*& p);</TT>
|
||
|
|
<H3>
|
||
|
|
<A NAME="structs"></A>Binding struct fields</H3>
|
||
|
|
User defined types are nicely bound by <B>tolua</B>. For each variable
|
||
|
|
or function type that does not correspond to a basic type, <B>tolua </B>automatically
|
||
|
|
creates a tagged userdata to represent the C/C++ type. If the type corresponds
|
||
|
|
to a struct, the struct fields can be directly accessed from Lua, indexing
|
||
|
|
a variable that holds an object of such a type. In C code, these types
|
||
|
|
are commonly defined using typedef's:
|
||
|
|
<PRE><B>typedef struct [name]</B><I> </I><B>{
|
||
|
|
</B> <I>type1 fieldname1</I><B>;
|
||
|
|
</B> <I>type2 fieldname2</I><B>;
|
||
|
|
</B> ...
|
||
|
|
<I>typeN fieldnameN</I><B>;
|
||
|
|
} </B><I>typename</I><B>;</B></PRE>
|
||
|
|
If such a code is inserted in the package file being processed, <B>tolua
|
||
|
|
</B>allows
|
||
|
|
any variable that holds an object of type <I><TT>typename </TT></I>to access
|
||
|
|
any listed field indexing the variable by the field name. For instance,
|
||
|
|
if <TT>var </TT>holds a such object, <I><TT>var.fieldnamei</TT></I> accesses
|
||
|
|
the field named <I><TT>fieldnamei</TT></I>.
|
||
|
|
<P>Fields that represent arrays of values can also be mapped:
|
||
|
|
<P><TT>typedef struct {</TT>
|
||
|
|
<BR><TT> int x[10];</TT>
|
||
|
|
<BR><TT> int y[10];</TT>
|
||
|
|
<BR><TT>} Example;</TT>
|
||
|
|
<BR>
|
||
|
|
<H3>
|
||
|
|
<A NAME="classes"></A>Binding classes and methods</H3>
|
||
|
|
C++ class definitions are also supported by <B>tolua</B>. Actually, the
|
||
|
|
<B>tolua
|
||
|
|
</B>deals
|
||
|
|
with single inheritance and polymorphism in a natural way. The subsections
|
||
|
|
below describe what can be exported by a class definition.
|
||
|
|
<H4>
|
||
|
|
Specifying inheritance</H4>
|
||
|
|
If <TT>var </TT>is a Lua variable that holds an object of a derived class,
|
||
|
|
<TT>var
|
||
|
|
</TT>can
|
||
|
|
be used wherever its base class type is expected and <TT>var
|
||
|
|
</TT>can access
|
||
|
|
any method of its base class. For this mechanism to take effect, we must
|
||
|
|
indicate that the derived class actually inherits the base class. This
|
||
|
|
is done in the conventional way:
|
||
|
|
<PRE><B>class </B><I>classname </I><B>: public</B> <I>basename
|
||
|
|
</I><B>{</B></PRE>
|
||
|
|
|
||
|
|
<PRE> /* class definition */</PRE>
|
||
|
|
|
||
|
|
<PRE><B>};</B></PRE>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
In this case, the definition of <tt>basename</tt> needs to appear before <tt>classname</tt>
|
||
|
|
if the inheritance properties are to be taken advantage of from lua.
|
||
|
|
|
||
|
|
<h4>Multiple inheritance</h4>
|
||
|
|
|
||
|
|
<b>tolua++</b> (starting from version 1.0.4) supports multiple inheritance by allowing you
|
||
|
|
to access the extra parents 'manually'.
|
||
|
|
<p>
|
||
|
|
For example, consider the following class:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<PRE>
|
||
|
|
class Slider : public Widget, public Range {
|
||
|
|
...
|
||
|
|
};
|
||
|
|
</PRE>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
An object of type 'Slider' will fully retain its inheritance with Widget,
|
||
|
|
and will contain a 'member' of type Range, which will return the object
|
||
|
|
cast to the correct base type.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
For example:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<PRE>
|
||
|
|
slider = Slider:new()
|
||
|
|
slider:show() -- a Widget method
|
||
|
|
|
||
|
|
slider:set_range(0, 100) -- this won't work, because
|
||
|
|
-- set_range is a method from Range
|
||
|
|
|
||
|
|
slider.__Range__:set_range(0, 100) -- this is the correct way
|
||
|
|
</PRE>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
|
||
|
|
This is an experimental feature.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<H4>
|
||
|
|
Specifying exported members and methods</H4>
|
||
|
|
As for struct fields, class fields, static or not, can be exported. Class
|
||
|
|
methods and class static methods can also be exported. Of course, they
|
||
|
|
must be declared as public in the actual C++ code (the
|
||
|
|
<TT>public:</TT>keyword may appear in the package files, it will be ignored by <b>tolua</b>).
|
||
|
|
<P>For each bound class, <B>tolua </B>creates a Lua table and stores it
|
||
|
|
at a variable which name is the name of the C++ class. This tables may contain other
|
||
|
|
tables that represent other tables, the way C++ classes may contain other classes and structs.
|
||
|
|
Static exported
|
||
|
|
fields are accessed by indexing this table with the field names (similar
|
||
|
|
to struct fields). Static methods are also called using this table, with a colon.
|
||
|
|
Non static exported fields are accessed by indexing
|
||
|
|
the variable that holds the object. Class methods follow the format of
|
||
|
|
the function declaration showed above. They can be accessed from Lua code
|
||
|
|
using the conventional way Lua uses to call methods, applied of course
|
||
|
|
to a variable that holds the appropriate object or to the class table,
|
||
|
|
for static methods.
|
||
|
|
<P>There are a few special methods that are also supported by <B>tolua</B>.
|
||
|
|
Constructors are called as static methods, named <TT>new</TT>, <tt>new_local</tt> (on <b>tolua++</b>),
|
||
|
|
or calling the class name directly (also on <b>tolua++</b>, see below for the difference betwheen these methods). Destructors
|
||
|
|
are called as a conventional method called <TT>delete</TT>.
|
||
|
|
<P>Note that <B>tolua </B>does support overload. This applies even for
|
||
|
|
constructors. Also note that the <TT>virtual </TT>keyword has no effect
|
||
|
|
in the package file.
|
||
|
|
<P>The following code exemplifies class definitions that can be interpreted
|
||
|
|
by <B>tolua</B>.
|
||
|
|
<PRE>class Point {
|
||
|
|
static int n; // represents the total number of created Points
|
||
|
|
static int get_n(); // static method
|
||
|
|
|
||
|
|
double x; // represents the x coordinate
|
||
|
|
double y; // represents the y coordinate</PRE>
|
||
|
|
|
||
|
|
<PRE> static char* className (void); // returns the name of the class</PRE>
|
||
|
|
|
||
|
|
<PRE> Point (void); // constructor 1
|
||
|
|
Point (double px, double py); // constructor 2
|
||
|
|
~Point (void); // destructor</PRE>
|
||
|
|
|
||
|
|
<PRE> Point add (Point& other); // add points, returning another one
|
||
|
|
};</PRE>
|
||
|
|
|
||
|
|
<PRE>class ColorPoint : public Color {
|
||
|
|
int red; // red color component [0 - 255]
|
||
|
|
int green; // green color component [0 - 255]
|
||
|
|
int blue; // blue color component [0 - 255]</PRE>
|
||
|
|
|
||
|
|
<PRE> ColorPoint (double px, double py, int r, int g, int b);
|
||
|
|
};</PRE>
|
||
|
|
If this segment of code is processed by <B>tolua</B>, we would be able
|
||
|
|
to write the following Lua statements:
|
||
|
|
<PRE>p1 = Point:new(0.0,1.0)
|
||
|
|
p2 = ColorPoint:new(1.5,2.2,0,0,255)
|
||
|
|
print(Point.n) -- would print 2
|
||
|
|
print(Point:get_n()) -- would also print 2
|
||
|
|
p3 = p1:add(p2)
|
||
|
|
local p4 = ColorPoint()
|
||
|
|
print(p3.x,p3.y) -- would print 1.5 and 3.2
|
||
|
|
print(p2.red,p2.green,p2.blue) -- would print 0, 0, and 255
|
||
|
|
p1:delete() -- call destructor
|
||
|
|
p2:delete() -- call destructor</PRE>
|
||
|
|
|
||
|
|
Note that we can only explicitly delete objects that we explicitly create.
|
||
|
|
In the example above, the point <TT>p3</TT> will be garbage-collected by
|
||
|
|
<B>tolua
|
||
|
|
</B>automatically;
|
||
|
|
we cannot delete it.
|
||
|
|
<p>
|
||
|
|
<b>New on tolua++</b>: Also note that <tt>p4</tt> is created by calling the class name directly (<tt>ColorPoint()</tt>); this has the same effect as calling <tt>new_local</tt>, which
|
||
|
|
leaves the object to be deleted by the garbaje collector, and it should not be
|
||
|
|
deleted using <tt>delete</tt>. For each constructor on the pkg, one <tt>new</tt>,
|
||
|
|
<tt>new_local</tt> and <tt>.call</tt> callback for the class is created.
|
||
|
|
<P>Of course, we need to specify only the methods and members we want to
|
||
|
|
access from Lua. Sometimes, it will be necessary to declare a class with
|
||
|
|
no member or method just for the sake of not breaking a chain of inheritances.
|
||
|
|
|
||
|
|
<h4>Using Regular functions as class methods</h4>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<b>tolua++</b> (starting from version 1.0.5) uses the keyword <b>tolua_outside</b> to specify regular functions
|
||
|
|
as methods and static methods of a class or struct. For example:
|
||
|
|
|
||
|
|
<PRE><tt>
|
||
|
|
/////////////// position.h:
|
||
|
|
|
||
|
|
typedef struct {
|
||
|
|
|
||
|
|
int x;
|
||
|
|
int y;
|
||
|
|
} Position;
|
||
|
|
|
||
|
|
Position* position_create();
|
||
|
|
void position_set(Position* pos, int x, int y);
|
||
|
|
|
||
|
|
/////////////// position.pkg:
|
||
|
|
|
||
|
|
struct Position {
|
||
|
|
|
||
|
|
int x;
|
||
|
|
int y;
|
||
|
|
|
||
|
|
static tolua_outside Position* position_create @ create();
|
||
|
|
tolua_outside void position_set @ set(int x, int y);
|
||
|
|
};
|
||
|
|
|
||
|
|
--------------- position.lua
|
||
|
|
|
||
|
|
local pos = Position:create()
|
||
|
|
|
||
|
|
pos:set(10, 10)
|
||
|
|
|
||
|
|
</tt></pre>
|
||
|
|
|
||
|
|
Note that the <b>position_set</b> method takes a pointer to <b>Position</b> as its first parameter,
|
||
|
|
this is ommited on the <b>tolua_outside</b> declaration. Also note that we cannot name our methods
|
||
|
|
<b>new</b> or <b>new_local</b>, or as overloaded operators (see next section), this will result in
|
||
|
|
undefined behaviour.
|
||
|
|
|
||
|
|
|
||
|
|
<H4>
|
||
|
|
Overloaded operators</H4>
|
||
|
|
<B>tolua </B>automatically binds the following binary operators:
|
||
|
|
<UL>
|
||
|
|
<PRE>operator+ operator- operator* operator/
|
||
|
|
operator< operator>= operator== operator[]</PRE>
|
||
|
|
</UL>
|
||
|
|
For the relational operators, <B>toLua </B>also automatically converts
|
||
|
|
a returned <TT>0</TT> value into <TT>nil</TT>, so <I>false </I>in C becomes
|
||
|
|
<I>false
|
||
|
|
</I>in
|
||
|
|
Lua.
|
||
|
|
<P>As an example, suppose that in the code above, instead of having:
|
||
|
|
<PRE> Point add (Point& other); // add points, returning another one</PRE>
|
||
|
|
we had:
|
||
|
|
<PRE> Point operator+ (Point& other); // add points, returning another one</PRE>
|
||
|
|
In that case, in Lua, we could simply write:
|
||
|
|
<PRE>p3 = p1 + p2</PRE>
|
||
|
|
The indexing operator (<TT>operator[]</TT>) when receiving a numeric parameter
|
||
|
|
can also be exported to Lua. In this case, <B>tolua </B>accepts reference
|
||
|
|
as returned value, even for basic types. Then if a reference is returned,
|
||
|
|
from Lua, the programmer can either get or set the value. If the returned
|
||
|
|
value is not a reference, the programmer can only get the value. An example
|
||
|
|
may clarify: suppose we have a vector class and bind the following operator:
|
||
|
|
<PRE> double& operator[] (int index);</PRE>
|
||
|
|
In this case, in Lua, we would be able to write: <TT>value = myVector[i]</TT>
|
||
|
|
and also <TT>myVector[i] = value</TT>, which updates the C++ object. However,
|
||
|
|
if the bound operator was:
|
||
|
|
<PRE> double operator[] (int index);</PRE>
|
||
|
|
we would only be able to write: <TT>value = myVector[i]</TT>.
|
||
|
|
<P>Free functions (i.e., not class members) that overload operators are
|
||
|
|
not supported.
|
||
|
|
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<H4>
|
||
|
|
Cast operators</H4>
|
||
|
|
|
||
|
|
<b>New on tolua++</b> (versions 1.0.90 and up): casting operators are also supported.
|
||
|
|
For example:
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
/////////////// node.h
|
||
|
|
|
||
|
|
// a class that holds a value that can be of type int, double, string or Object*
|
||
|
|
class Node { // tolua_export
|
||
|
|
|
||
|
|
private:
|
||
|
|
union {
|
||
|
|
int int_value;
|
||
|
|
double double_value;
|
||
|
|
string string_value;
|
||
|
|
Object* object_value;
|
||
|
|
};
|
||
|
|
|
||
|
|
// tolua_begin
|
||
|
|
public:
|
||
|
|
|
||
|
|
enum Type {
|
||
|
|
T_INT,
|
||
|
|
T_DOUBLE,
|
||
|
|
T_STRING,
|
||
|
|
T_OBJECT,
|
||
|
|
T_MAX,
|
||
|
|
};
|
||
|
|
|
||
|
|
Type get_type();
|
||
|
|
|
||
|
|
operator int();
|
||
|
|
operator double();
|
||
|
|
operator string();
|
||
|
|
operator Object*();
|
||
|
|
};
|
||
|
|
// tolua_end
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
<b>tolua++</b> will produce code that calls the operators by casting the object Node (using C++ <tt>static_cast</tt>),
|
||
|
|
and register them inside the class as ".typename". For example:
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
-- node.lua
|
||
|
|
|
||
|
|
local node = list.get_node("some_node") -- returns a Node object
|
||
|
|
|
||
|
|
if node.get_type() == Node.T_STRING then
|
||
|
|
|
||
|
|
print("node is "..node[".string"]())
|
||
|
|
|
||
|
|
elseif node.get_type() == Node.T_OBJECT then
|
||
|
|
|
||
|
|
local object = node[".Object*"]()
|
||
|
|
object:method()
|
||
|
|
end
|
||
|
|
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
<h3><a name="properties"></a>Binding Properties</h3>
|
||
|
|
|
||
|
|
<b>tolua++</b> (starting from version 1.0.6) supports declaration of class propeties,
|
||
|
|
using the <tt>tolua_property</tt> keyword. A
|
||
|
|
property will look like a 'field' of the class, but it's value will be retrieved
|
||
|
|
using class methods. For example:
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
/////////////// label.h
|
||
|
|
|
||
|
|
class Label {
|
||
|
|
|
||
|
|
public:
|
||
|
|
|
||
|
|
string get_name();
|
||
|
|
void set_name(string p_name);
|
||
|
|
|
||
|
|
Widget* get_parent();
|
||
|
|
};
|
||
|
|
|
||
|
|
/////////////// label.pkg
|
||
|
|
class Label {
|
||
|
|
|
||
|
|
tolua_property string name;
|
||
|
|
|
||
|
|
tolua_readonly tolua_property Widget* parent;
|
||
|
|
};
|
||
|
|
|
||
|
|
--------------- label.lua
|
||
|
|
|
||
|
|
local label = Label()
|
||
|
|
|
||
|
|
label.name = "hello"
|
||
|
|
print(label.name)
|
||
|
|
|
||
|
|
label.parent:show()
|
||
|
|
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
<h4>Property types</h4>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
A property can have differt types, which determine how it's value will be set and retrieved.
|
||
|
|
<b>tolua++</b> comes with 3 different built-in types:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<li> <tt>default</tt> will use 'get_name' and 'set_name' methods to access a property called 'name'
|
||
|
|
<li> <tt>qt</tt> will use 'name' and 'setName'
|
||
|
|
<li> <tt>overload</tt> will use 'name' and 'name' (as in 'string name(void);' to get and 'void name(string);' to set)
|
||
|
|
<p>
|
||
|
|
|
||
|
|
The property type can be appended at the end of the 'tolua_property' keyword on the declaration:
|
||
|
|
|
||
|
|
<ul><tt>tolua_property__qt string name;</tt></ul>
|
||
|
|
|
||
|
|
When no type is specified, <tt>default</tt> will be used, but this can be changed (see below).
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<h4>Changing the default property type</h4>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
The default property type can be changed using the 'TOLUA_PROPERTY_TYPE' macro. This will change the
|
||
|
|
default type from the point of its invocation, until the end of the block that contains it. For example:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
|
||
|
|
TOLUA_PROPERTY_TYPE(default); // default type for the 'global' scope
|
||
|
|
|
||
|
|
namespace GUI {
|
||
|
|
|
||
|
|
class Point {
|
||
|
|
|
||
|
|
tolua_property int x; // will use get_x/set_x
|
||
|
|
tolua_property int y; // will use get_y/set_y
|
||
|
|
};
|
||
|
|
|
||
|
|
TOLUA_PROPERTY_TYPE(qt); // changes default type to 'qt' for the rest of the 'GUI' namespace
|
||
|
|
|
||
|
|
class Label {
|
||
|
|
|
||
|
|
tolua_property string name; // will use name/setName
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
class Sprite {
|
||
|
|
|
||
|
|
tolua_property GUI::Point position; // will use get_position/set_position
|
||
|
|
|
||
|
|
tolua_property__overload string name; // will use name/name
|
||
|
|
};
|
||
|
|
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
<h4>Adding custom property types</h4>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
Custom property types can be added by redefining the function "get_property_methods_hook"
|
||
|
|
(see <a href="#customizing">Customizing tolua++</a> for more details). The functions takes
|
||
|
|
the property type and the name, and returns the setter and getter function names. For example:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
|
||
|
|
/////////////// custom.lua
|
||
|
|
|
||
|
|
function get_property_methods_hook(ptype, name)
|
||
|
|
|
||
|
|
if ptype == "hungarian_string" then
|
||
|
|
|
||
|
|
return "sGet"..name, "Set"..name
|
||
|
|
end
|
||
|
|
|
||
|
|
if ptype == "hungarian_int" then
|
||
|
|
|
||
|
|
return "iGet"..name, "Set"..name
|
||
|
|
end
|
||
|
|
-- etc
|
||
|
|
end
|
||
|
|
|
||
|
|
/////////////// label.pkg
|
||
|
|
class Label {
|
||
|
|
|
||
|
|
tolua_property__hungarian_string string Name; // uses 'sGetName' and 'SetName'
|
||
|
|
|
||
|
|
tolua_property__hungarian_int string Type; // uses 'iGetType' and 'SetType'
|
||
|
|
};
|
||
|
|
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
<h3><a name="templates"></a>Class Templates</h3>
|
||
|
|
|
||
|
|
One of the additional features of <b>tolua++</b> is the support for class templates,
|
||
|
|
by using the <tt>TOLUA_TEMPLATE_BIND</tt> directive. For example:
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
class vector {
|
||
|
|
|
||
|
|
TOLUA_TEMPLATE_BIND(T, int, string, Vector3D, double)
|
||
|
|
|
||
|
|
void clear();
|
||
|
|
int size() const;
|
||
|
|
|
||
|
|
const T& operator[](int index) const;
|
||
|
|
T& operator[](int index);
|
||
|
|
void push_back(T val);
|
||
|
|
|
||
|
|
vector();
|
||
|
|
~vector();
|
||
|
|
};
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
The <tt>TOLUA_TEMPLATE_BIND</tt> directive has to be the first thing on the class declaration, otherwise it will be ignored.
|
||
|
|
This code will create 4 versions of the class <tt>vector</tt>, one for each type
|
||
|
|
specified on the <tt>TOLUA_TEMPLATE_BIND</tt> parameters, each replacing the macro <tt>T</tt>
|
||
|
|
(specified as the first argument of <tt>TOLUA_TEMPLATE_BIND</tt>).
|
||
|
|
Thus, the functions <tt>operator[]</tt>, <tt>&operator[]</tt> and <tt>push_back</tt>
|
||
|
|
will have different signatures on each version of the object. The objects will be
|
||
|
|
recognized as <tt>vector<type></tt> on further declarations, and the name of
|
||
|
|
the table on Lua will be <tt>vector_type_</tt>. Thus, the following Lua code could be used:
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
string_vector = vector_string_:new_local()
|
||
|
|
string_vector:push_back("hello")
|
||
|
|
string_vector:push_back("world")
|
||
|
|
print(string_vector[0].." "..string_vector[1])
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
Similarily, a template with more than 1 macro could be bound, and it could also
|
||
|
|
inherit from another template:
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
class hash_map : public map<K,V> {
|
||
|
|
|
||
|
|
TOLUA_TEMPLATE_BIND(K V, int string, string vector<double>)
|
||
|
|
|
||
|
|
V get_element(K key);
|
||
|
|
void set_element(K key, V value);
|
||
|
|
|
||
|
|
hash_map();
|
||
|
|
~hash_map();
|
||
|
|
};
|
||
|
|
</tt></pre>
|
||
|
|
|
||
|
|
In this example, one of the objects has another template as one of its types, so
|
||
|
|
it will be recognized as <tt>hash_map<string,vector<double> ></tt> while
|
||
|
|
its constructor will be on the Lua table hash_map_string_vector_double___ (see
|
||
|
|
<a href="#type_renaming">Type Renaming</a> for a better way to access these objects).
|
||
|
|
<p>
|
||
|
|
|
||
|
|
Note that due to the complexity in the definition of some templates, you should be
|
||
|
|
careful on how you declare them. For example, if you create an object with type
|
||
|
|
<tt>hash_map<string,vector<double> ></tt> and then declare a variable
|
||
|
|
with type <tt>hash_map<string, vector<double> ></tt> (note the space
|
||
|
|
between string and vector), the type of the variable will not be recognized. The
|
||
|
|
safest way is to declare a typedef, and use that to use each type (this is also a
|
||
|
|
common practice on C++ programming). For example, using the previous declaration of
|
||
|
|
<tt>vector</tt>:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
typedef vector<int> VectorInt;
|
||
|
|
|
||
|
|
VectorInt variable;
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
<tt>TOLUA_TEMPLATE_BIND</tt> can be used with more than one parenthesis to open and close,
|
||
|
|
in order to be valid as a macro inside a regular .h file. The <tt>TOLUA_TEMPLATE_BIND</tt>
|
||
|
|
macro is declared on <tt>tolua.h</tt> as:
|
||
|
|
<p>
|
||
|
|
<tt>#define TOLUA_TEMPLATE_BIND(x)</tt>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
Also, the parameters can have double quotes. Thus, the following uses are valid:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
TOLUA_TEMPLATE_BIND((T, int, float)) // to be used inside a real header file
|
||
|
|
TOLUA_TEMPLATE_BIND("K V", "string string", int double)
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
Function templates are not supported on this version.
|
||
|
|
|
||
|
|
<H3>
|
||
|
|
<A NAME="modules"></A>Module definition</H3>
|
||
|
|
<B>tolua </B>allows us to group constants, variables, and functions in
|
||
|
|
a module. The module itself is mapped to a table in Lua, and its constants,
|
||
|
|
variables, and functions are mapped to fields in that table. The general
|
||
|
|
format to specify a module is:
|
||
|
|
<P><TT><B>module</B> name</TT>
|
||
|
|
<BR><B><TT>{</TT></B>
|
||
|
|
<BR><TT> ... // constant, variable, and function
|
||
|
|
declarations</TT>
|
||
|
|
<BR><B><TT>}</TT></B>
|
||
|
|
<P>Thus, if we bound the following module declaration:
|
||
|
|
<P><TT>module mod</TT>
|
||
|
|
<BR><TT>{</TT>
|
||
|
|
<BR><TT> #define N</TT>
|
||
|
|
<BR><TT> extern int var;</TT>
|
||
|
|
<BR><TT> int func (...):</TT>
|
||
|
|
<BR><TT>}</TT>
|
||
|
|
<P>In Lua we would be able to access such features by indexing the module:
|
||
|
|
<TT>mod.N</TT>,
|
||
|
|
<TT>mod.var</TT>,
|
||
|
|
<TT>mod.func</TT>.
|
||
|
|
<H3>
|
||
|
|
<A NAME="renaming"></A>Renaming constants, variables and functions</H3>
|
||
|
|
When exporting constants, variable, and functions (members of a class or
|
||
|
|
not), we can rename them, such that they will be bound with a different
|
||
|
|
name from their C/C++ counterparts. To do that, we write the name they
|
||
|
|
will be referenced in Lua after the character <TT>@</TT>. For instance:
|
||
|
|
<P><TT>extern int cvar @ lvar;</TT>
|
||
|
|
<P><TT>#define CNAME @ LNAME</TT>
|
||
|
|
<P><TT>enum {</TT>
|
||
|
|
<BR><TT> CITEM1 @ LITEM1,</TT>
|
||
|
|
<BR><TT> CITEM2 @ LITEM2,</TT>
|
||
|
|
<BR><TT> ...</TT>
|
||
|
|
<BR><TT>};</TT>
|
||
|
|
<P><TT>void cfunc @ lfunc (...);</TT>
|
||
|
|
<P><TT>class T</TT>
|
||
|
|
<BR><TT>{</TT>
|
||
|
|
<BR><TT> double cfield @ lfield;</TT>
|
||
|
|
<BR><TT> void cmeth @ lmeth (...);</TT>
|
||
|
|
<BR><TT> ...</TT>
|
||
|
|
<BR><TT>};</TT>
|
||
|
|
<P>In such a case, the global variable <TT>cvar </TT>would be identified
|
||
|
|
in Lua by <TT>lvar</TT>, the constant <TT>CNAME </TT>by <TT>LNAME</TT>,
|
||
|
|
and so on. Note that class cannot be renamed, because they represent types
|
||
|
|
in C.
|
||
|
|
<P>This renaming feature allows function overload in C, because we can
|
||
|
|
choose to export two different C functions with a same Lua name:
|
||
|
|
<P><TT>void glVertex3d @ glVertex (double x, double y, double z=0.0);</TT>
|
||
|
|
<BR><TT>void glVertexdv @ glVertex (double v[3]=0.0);</TT>
|
||
|
|
|
||
|
|
<a name="type_renaming"></a><h3>Renaming Types</h3>
|
||
|
|
|
||
|
|
Types can be renamed using the <tt>$renaming</tt> directive on pkg files, using the
|
||
|
|
format:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<tt>$renaming real_name @ new_name</tt>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
The parameters to renaming can be Lua <i>patterns</i>. For example:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
$renaming ^_+ @
|
||
|
|
$renaming hash_map<string,vector<double> > @ StringHash
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
The first example will remove all underscores at the beginning of all types,
|
||
|
|
the second will rename the template type hash_map<string,vector<double> >
|
||
|
|
to StringHash. Once renamed, the Lua table for each type can be accessed only by their
|
||
|
|
new name, for example: <tt>StringHash:new()</tt>
|
||
|
|
|
||
|
|
<A NAME="additional"></A><h3>Storing additional fields</H3>
|
||
|
|
Finally, it is important to know that even though the variables that hold
|
||
|
|
C/C++ objects are actually tagged userdata for Lua,<B> tolua</B> creates
|
||
|
|
a mechanism that allows us to store any additional field attached to these
|
||
|
|
objects. That is, these objects can be seen as conventional Lua tables.
|
||
|
|
<PRE>obj = <I>ClassName</I>:new()</PRE>
|
||
|
|
|
||
|
|
<PRE>obj.myfield = 1 -- even though "myfield" does not represent a field of ClassName</PRE>
|
||
|
|
Such a construction is possible because, if needed, <B>tolua </B>automatically
|
||
|
|
creates a Lua table and associates it with the object. So that, the object
|
||
|
|
can store additional fields not mapped to C/C++, but actually stored in
|
||
|
|
the conjugate table. The Lua programmer accesses the C/C++ features and
|
||
|
|
these additional fields in an uniform way. Note that, in fact, these additional
|
||
|
|
fields overwrite C/C++ fields or methods when the names are the same.
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
<a name="additional_features"></a><h3>Additional features on tolua++</h3>
|
||
|
|
|
||
|
|
<h4>Multiple variable declarations</h4>
|
||
|
|
|
||
|
|
Multiple variables of the same type can be declared at the same time, for example:
|
||
|
|
<p>
|
||
|
|
<tt>float x,y,z;</tt>
|
||
|
|
<p>
|
||
|
|
will create 3 different variables of type float. Make sure you don't leave any
|
||
|
|
spaces between the commas, as that will raise a parse error.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<h4>tolua_readonly</h4>
|
||
|
|
|
||
|
|
Any variable declaration can use the <tt>tolua_readonly</tt> modifier, to ensure
|
||
|
|
that the variable is read-only, even when its type is not <tt>const</tt>. Example:
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
class Widget {
|
||
|
|
|
||
|
|
tolua_readonly string name;
|
||
|
|
};
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
This feature could be used to 'hack' the support for other unsupported things like
|
||
|
|
<tt>operator-></tt>. Consider this example <tt>pkg</tt> file:
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
$hfile "node.h"
|
||
|
|
$#define __operator_arrow operator->()
|
||
|
|
$#define __get_name get_name()
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
And on the file <tt>node.h</tt>:
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
template class<T>
|
||
|
|
class Node { // tolua_export
|
||
|
|
|
||
|
|
private:
|
||
|
|
string name;
|
||
|
|
T* value;
|
||
|
|
|
||
|
|
public:
|
||
|
|
|
||
|
|
T* operator->() {return value;};
|
||
|
|
string get_name() {return name;};
|
||
|
|
|
||
|
|
// tolua_begin
|
||
|
|
|
||
|
|
#if 0
|
||
|
|
TOLUA_TEMPLATE_BIND(T, Vector3D)
|
||
|
|
|
||
|
|
tolua_readonly __operator_arrow @ p;
|
||
|
|
tolua_readonly __get_name @ name;
|
||
|
|
#endif
|
||
|
|
|
||
|
|
|
||
|
|
Node* next;
|
||
|
|
Node* prev;
|
||
|
|
|
||
|
|
void set_name(string p_name) {name = p_name;};
|
||
|
|
|
||
|
|
Node();
|
||
|
|
};
|
||
|
|
// tolua_end
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
While not a pretty thing to do to a header file, this accomplishes a number of
|
||
|
|
things:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<li> The method <tt>operator->()</tt> can be used from Lua by calling the variable
|
||
|
|
<tt>p</tt> on the object.</li>
|
||
|
|
<li> The method <tt>get_name()</tt> can be using from Lua by calling the variable
|
||
|
|
<tt>name</tt> on the boject.</li>
|
||
|
|
|
||
|
|
Example lua usage:
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
node = Node_Vector3D_:new_local()
|
||
|
|
-- do something with the node here --
|
||
|
|
print("node name is "..node.name)
|
||
|
|
print("node value is ".. node.p.x ..", ".. node.p.y ..", ".. node.p.z)
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
Since <b>tolua++</b> ignores all preprocessor directives (except for #define), <tt>node.h</tt>
|
||
|
|
remains a valid C++ header file, and also a valid source for <b>tolua++</b>,
|
||
|
|
eliminating the need to maintain 2 different files, even for objects with
|
||
|
|
unusual features such as these ones.
|
||
|
|
|
||
|
|
<p>
|
||
|
|
|
||
|
|
The ability to rename functions as variables might be expanded on future versions.
|
||
|
|
|
||
|
|
<h4>Defining values on command line</h4>
|
||
|
|
|
||
|
|
Starting from version 1.0.92, the command line option <tt>-E</tt> allows
|
||
|
|
you to introduce values into to the luastate where <b>tolua++</b> runs,
|
||
|
|
similar to GCC's <tt>-D</tt>. For example:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<pre>$ tolua++ -E VERSION=5.1 -E HAVE_ZLIB package.pkg > package_bind.cpp</pre>
|
||
|
|
|
||
|
|
<p>
|
||
|
|
This will add 2 fields to the global table <tt>_extra_parameters</tt>:
|
||
|
|
"VERSION", with the string value "5.1", and "HAVE_ZLIB" with the boolean value
|
||
|
|
<tt>true</tt>. For the moment, there is no way to 'use' these values, except
|
||
|
|
in custom scripts defined by the user (see
|
||
|
|
<a href="#customizing">customizing tolua++</a> for details).
|
||
|
|
|
||
|
|
<h4>Using C++ typeid</h4>
|
||
|
|
|
||
|
|
Starting from version 1.0.92, the command line option <tt>-t</tt> is available,
|
||
|
|
which generates a list of calls to the empty macro <tt>Mtolua_typeid</tt>, with its
|
||
|
|
C++ <tt>type_info object</tt>, and the name used by tolua++ to identify the type. For example,
|
||
|
|
if you have a package that binds 2 classes, <tt>Foo</tt> and <tt>Bar</tt>, using <tt>-t</tt>
|
||
|
|
will produce the following output:
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
#ifndef Mtolua_typeid
|
||
|
|
#define Mtolua_typeid(L,TI,T)
|
||
|
|
#endif
|
||
|
|
Mtolua_typeid(tolua_S,typeid(Foo), "Foo");
|
||
|
|
Mtolua_typeid(tolua_S,typeid(Bar), "Bar");
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
The implementation of Mtolua_typename is left as an exercise to the user.
|
||
|
|
|
||
|
|
<H3>
|
||
|
|
<A NAME="utilities"></A>Exported utility functions</H3>
|
||
|
|
<B>tolua </B>uses itself to export some utility functions to Lua, including
|
||
|
|
its object-oriented framework. The package file used by <B>tolua </B>is
|
||
|
|
|
||
|
|
shown below:
|
||
|
|
<P><TT>module tolua</TT>
|
||
|
|
<BR><TT>{</TT>
|
||
|
|
<BR><TT> char* tolua_bnd_type @ type (lua_Object lo);</TT>
|
||
|
|
|
||
|
|
<BR><TT> void tolua_bnd_takeownership @ takeownership (lua_Object lo);</TT>
|
||
|
|
<BR><TT> void tolua_bnd_releaseownership @ releaseownership (lua_Object lo);</TT>
|
||
|
|
|
||
|
|
<BR><TT> lua_Object tolua_bnd_cast @ cast (lua_Object lo, char* type);</TT>
|
||
|
|
|
||
|
|
<BR><TT> void tolua_bnd_inherit @ inherit (lua_Object table, lua_Object instance);</TT>
|
||
|
|
<p>
|
||
|
|
<TT>/* for lua 5.1 */</tt>
|
||
|
|
<BR><TT> void tolua_bnd_setpeer @ setpeer (lua_Object object, lua_Object peer_table);</TT>
|
||
|
|
<BR><TT> void tolua_bnd_getpeer @ getpeer (lua_Object object);</TT>
|
||
|
|
|
||
|
|
<BR><TT>}</TT>
|
||
|
|
|
||
|
|
<H4>
|
||
|
|
tolua.type (<I>var</I>)</H4>
|
||
|
|
Returns a string representing the object type. For instance, <TT>tolua.type(tolua)</TT>
|
||
|
|
returns the string <TT>table</TT> and <TT>tolua.type(tolua.type)</TT>
|
||
|
|
returns <TT>cfunction</TT>. Similarly, if <TT>var </TT>is a variable holding
|
||
|
|
a user defined type <TT>T</TT>, <TT>tolua.type(var)</TT> would return
|
||
|
|
<TT>const
|
||
|
|
T</TT> or <TT>T</TT>, depending whether it is a constant reference.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<h4>tolua.takeownership (<I>var</i>)</h4>
|
||
|
|
|
||
|
|
Takes ownership of the object referenced <i>var</i>. This means that when all references
|
||
|
|
to that object are lost, the objects itself will be deleted by lua.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<h4>tolua.releaseownership (<i>var</i>)</h4>
|
||
|
|
|
||
|
|
Releases ownership of the object referenced by <i>var</i>.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<h4>tolua.cast (<i>var</i>, <i>type</i>)</h4>
|
||
|
|
|
||
|
|
Changes the metatable of <i>var</i> in order to make it of type <i>type</i>. <i>type</i> needs
|
||
|
|
to be a string with the complete C type of the object (including namespaces, etc).
|
||
|
|
|
||
|
|
<h4>tolua.inherit (<i>table</i>, <i>var</i>)</h4> (new on <b>tolua++</b>)
|
||
|
|
|
||
|
|
Causes <b>tolua++</b> to recognise <i>table</i> as an object with the same type as <i>var</i>,
|
||
|
|
and to use <i>var</i> when necesary. For example, consider this method:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<ul><tt>void set_parent(Widget* p_parent);</tt></ul>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
A lua object could be used like this:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
local w = Widget()
|
||
|
|
local lua_widget = {}
|
||
|
|
tolua.inherit(lua_widget, w)
|
||
|
|
|
||
|
|
set_parent(lua_widget);
|
||
|
|
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
Remember that this will only cause the table to be recognised as type 'Widget' when
|
||
|
|
necesary. To be able to access Widget's methods, you'll have to implement your own
|
||
|
|
object system. A simple example:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
|
||
|
|
lua_widget.show = Widget.show
|
||
|
|
|
||
|
|
lua_widget:show() -- this will call the 'show' method from 'Widget', using the lua
|
||
|
|
-- table as 'self'. Since lua_widget inherits from a widget instance,
|
||
|
|
-- tolua++ will recognise 'self' as a 'Widget', and call the method
|
||
|
|
|
||
|
|
</pre>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
Of course a better way would be to add a __index metamethod for the lua object.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
Similarily, to implement virtual functions, you'll need to create a c++ object that inherits
|
||
|
|
from the desired type, implement its virtual functions, and use that to inherit from lua. The
|
||
|
|
object would have a reference to the lua table, and call its methods from the c++ virtual
|
||
|
|
methods.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<b>Note:</b> the current implementation (as of version 1.0.6) stores the C instance
|
||
|
|
inside the lua table on the field ".c_instance", and looks that up when necesary. This
|
||
|
|
might change in the future, so it is recommended to use an alternative way to store the
|
||
|
|
C instance to use with your own object system.
|
||
|
|
|
||
|
|
<h4>tolua.setpeer (<i>object</i>, <i>peer_table</i>) (lua 5.1 only)</h4>
|
||
|
|
|
||
|
|
Sets the table as the object's <i>peer</i> table (can be <tt>nil</tt>). The peer table is where all the custom
|
||
|
|
lua fields for the object are stored. When compiled with lua 5.1, <b>tolua++</b> stores the
|
||
|
|
peer as the object's <i>envirnment table</i>, and uses uses <tT>lua_gettable/settable</tT> (instead of
|
||
|
|
<tt>lua_rawget/set</tt> for lua 5.0) to retrieve and store fields on it. This allows us to implement our own
|
||
|
|
object system on our table (using metatables), and use it as a way to inherit from the userdata object.
|
||
|
|
Consider an alternative to the previous example:
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
-- a 'LuaWidget' class
|
||
|
|
LuaWidget = {}
|
||
|
|
LuaWidget.__index = LuaWidget
|
||
|
|
|
||
|
|
function LuaWidget:add_button(caption)
|
||
|
|
|
||
|
|
-- add a button to our widget here. 'self' will be the userdata Widget
|
||
|
|
end
|
||
|
|
|
||
|
|
|
||
|
|
local w = Widget()
|
||
|
|
local t = {}
|
||
|
|
setmetatable(t, LuaWidget) -- make 't' an instance of LuaWidget
|
||
|
|
|
||
|
|
tolua.setpeer(w, t) -- make 't' the peer table of 'w'
|
||
|
|
|
||
|
|
set_parent(w) -- we use 'w' as the object now
|
||
|
|
|
||
|
|
w:show() -- a method from 'Widget'
|
||
|
|
w:add_button("Quit") -- a method from LuaWidget (but we still use 'w' to call it)
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
When indexing our object, the peer table (if present) will be consulted first, so we
|
||
|
|
don't need to implement our own __index metamethod to call the C++ functions.
|
||
|
|
|
||
|
|
<h4>tolua.getpeer (<i>object</i>) (lua 5.1 only)</h4>
|
||
|
|
|
||
|
|
Retrieves the peer table from the object (can be <tt>nil</tt>).
|
||
|
|
|
||
|
|
<!--
|
||
|
|
<H3>
|
||
|
|
<A NAME="utilities"></A>Exported utility functions</H3>
|
||
|
|
<B>tolua </B>uses itself to export some utility functions to Lua, including
|
||
|
|
its object-oriented framework. The package file used by <B>tolua </B>is
|
||
|
|
shown below:
|
||
|
|
<P><TT>module tolua</TT>
|
||
|
|
<BR><TT>{</TT>
|
||
|
|
<BR><TT> void tolua_using @ using (lua_Table module);</TT>
|
||
|
|
<BR><TT> char* tolua_type @ type (lua_Object lo);</TT>
|
||
|
|
<BR><TT> void tolua_foreach @ foreach (lua_Object lo, lua_Function
|
||
|
|
f);</TT>
|
||
|
|
<BR><TT> void tolua_class @ class (lua_Table derived, lua_Table base=TOLUA_NIL);</TT>
|
||
|
|
<BR><TT> void tolua_instance @ instance (lua_Table instance, lua_Table
|
||
|
|
classobj);</TT>
|
||
|
|
<BR><TT> lua_Object tolua_base @ base (lua_Object lo);</TT>
|
||
|
|
<BR><TT>}</TT>
|
||
|
|
<H4>
|
||
|
|
tolua.using (<I>table</I>)</H4>
|
||
|
|
This functions receives a table and maps all its fields to the global environment.
|
||
|
|
Thus we can map an entire module and access its features without the module
|
||
|
|
prefix. For instance, if in our Lua code we do:
|
||
|
|
<P><TT>tolua.using(tolua)</TT>
|
||
|
|
<P>all <B>tolua </B>utility functions are mapped to the global environment.
|
||
|
|
<H4>
|
||
|
|
tolua.type (<I>var</I>)</H4>
|
||
|
|
Returns a string representing the object type. For instance, <TT>tolua.type(tolua)</TT>
|
||
|
|
returns the string <TT>generic module</TT> and <TT>tolua.type(tolua.type)</TT>
|
||
|
|
returns <TT>cfunction</TT>. Similarly, if <TT>var </TT>is a variable holding
|
||
|
|
a user defined type <TT>T</TT>, <TT>tolua.type(var)</TT> would return
|
||
|
|
<TT>const
|
||
|
|
T</TT> or <TT>T</TT>, depending whether it is a constant reference.
|
||
|
|
<H4>
|
||
|
|
tolua.tag (<I>"type"</I>)</H4>
|
||
|
|
Returns type corresponding tag number.
|
||
|
|
<H4>
|
||
|
|
tolua.foreach (<I>object</I>)</H4>
|
||
|
|
Allows us to traverse the conjugate table of an user defined instance.
|
||
|
|
If applied to conventional table, it has a similar behavior as the Lua
|
||
|
|
built-in <TT>foreach </TT>function. The difference is that this function
|
||
|
|
filters all fields starting with a dot, not passing them to the provided
|
||
|
|
callback function. This filter is need because <B>tolua </B>adds "hidden"
|
||
|
|
fields to the tables it manipulates, and all its "hidden" fields start
|
||
|
|
with a dot.
|
||
|
|
<H4>
|
||
|
|
tolua.cast (<I>object, "typename"</I>)</H4>
|
||
|
|
Returns the object "casted" to the given type. The object must represent
|
||
|
|
an user type, otherwise the function returns <B><TT>nil</TT></B>.
|
||
|
|
<H4>
|
||
|
|
tolua.takeownership (<I>object</I>)</H4>
|
||
|
|
Asks <B>tolua</B> to take the ownership of the given object. This means
|
||
|
|
the C/C++ object will be freed/ destructed when garbage-collected by Lua.
|
||
|
|
The object must represent an user type, otherwise an execution error is
|
||
|
|
generated.
|
||
|
|
<H4>
|
||
|
|
tolua.class (<I>table</I>, <I>base=nil</I>)</H4>
|
||
|
|
Creates a class by setting the appropriate tag methods to the given table.
|
||
|
|
The created class can inherit from a base class, previously created.
|
||
|
|
<H4>
|
||
|
|
tolua.instance (<I>table</I>, <I>class</I>)</H4>
|
||
|
|
Sets the given table to be an instance of the given class. This and the
|
||
|
|
previous utility functions allow object-oriented programming in Lua. As
|
||
|
|
an example consider:
|
||
|
|
<P><TT>-- define a Point class</TT>
|
||
|
|
<BR><TT>classPoint = { x=0, y=0 }</TT>
|
||
|
|
<BR><TT>tolua.class(classPoint) -- set as a class</TT>
|
||
|
|
<P><TT>-- define print method</TT>
|
||
|
|
<BR><TT>function classPoint:print ()</TT>
|
||
|
|
<BR><TT> print(self.x,self.y)</TT>
|
||
|
|
<BR><TT>end</TT>
|
||
|
|
<P><TT>-- define add method</TT>
|
||
|
|
<BR><TT>function classPoint:add (p2)</TT>
|
||
|
|
<BR><TT> return Point{x=self.x+p2.x,y=self.y+p2.y}</TT>
|
||
|
|
<BR><TT>end</TT>
|
||
|
|
<P><TT>-- define a Point constructor</TT>
|
||
|
|
<BR><TT>function Point (p)</TT>
|
||
|
|
<BR><TT> tolua.instance(p,classPoint) -- set as an instance
|
||
|
|
of classPoint</TT>
|
||
|
|
<BR><TT>return p end</TT>
|
||
|
|
<P><TT>-- define a Color Point class</TT>
|
||
|
|
<BR><TT>classColorPoint = { color = 'black' }</TT>
|
||
|
|
<BR><TT>tolua.class(classColorPoint,classPoint) -- set as class inheriting
|
||
|
|
from classPoint</TT>
|
||
|
|
<P><TT>-- define class methods</TT>
|
||
|
|
<BR><TT>function classColorPoint:print ()</TT>
|
||
|
|
<BR><TT> print(self.x,self.y,self.color)</TT>
|
||
|
|
<BR><TT>end</TT>
|
||
|
|
<P><TT>-- define Color Point constructor</TT>
|
||
|
|
<BR><TT>function ColorPoint (p)</TT>
|
||
|
|
<BR><TT> tolua.instance(p,classColorPoint) -- set as an instance
|
||
|
|
of classColorPoint</TT>
|
||
|
|
<BR><TT> return p</TT>
|
||
|
|
<BR><TT>end</TT>
|
||
|
|
<P><TT>-- Some valid codes would then be</TT>
|
||
|
|
<BR><TT>p = Point{x=1}</TT>
|
||
|
|
<BR><TT>q = ColorPoint{x=2,y=3,color=2}</TT>
|
||
|
|
<BR><TT>r = p:add(q)</TT>
|
||
|
|
<BR><TT>r:print() --> would print "3 3"</TT>
|
||
|
|
<BR>
|
||
|
|
-->
|
||
|
|
|
||
|
|
<H3>
|
||
|
|
<A NAME="embedded"></A>Embedded Lua code</H3>
|
||
|
|
<B>tolua</B> allows us to embed Lua code in the C/C++ generated code. To
|
||
|
|
do that, it compiles the specified Lua code and creates a C constant string,
|
||
|
|
storing the corresponding bytecodes, in the generated code. When
|
||
|
|
the package is opened, such a string is executed. The format to embed Lua
|
||
|
|
code is:
|
||
|
|
<P><B><TT>$[</TT></B>
|
||
|
|
<P><I><TT>embedded Lua code</TT></I>
|
||
|
|
<BR><I><TT>...</TT></I>
|
||
|
|
<P><B><TT>$]</TT></B>
|
||
|
|
<P>As an example consider the following .pkg excerpt:
|
||
|
|
<P><TT>/* Bind a Point class */</TT>
|
||
|
|
<BR><TT>class Point</TT>
|
||
|
|
<BR><TT>{</TT>
|
||
|
|
<BR><TT> Point (int x, int y);</TT>
|
||
|
|
<BR><TT> ~Point ();</TT>
|
||
|
|
<BR><TT> void print ();</TT>
|
||
|
|
<BR><TT> ...</TT>
|
||
|
|
<BR><TT>} CPoint;</TT>
|
||
|
|
<P><TT>$[</TT>
|
||
|
|
<P><TT>-- Create a Point constructor</TT>
|
||
|
|
<BR><TT>function Point (self)</TT>
|
||
|
|
<BR><TT> local cobj = CPoint:new(self.x or 0, self.y or 0)</TT>
|
||
|
|
<BR><TT> tolua.takeownership(cobj)</TT>
|
||
|
|
<BR><TT> return cobj</TT>
|
||
|
|
<BR><TT>end</TT>
|
||
|
|
<P><TT>$]</TT>
|
||
|
|
<P>Binding such a code would allow us to write the following Lua code:
|
||
|
|
<P><TT>p = Point{ x=2, y=3 }</TT>
|
||
|
|
<BR><TT>p:print()</TT>
|
||
|
|
<BR><TT>...</TT>
|
||
|
|
<BR>
|
||
|
|
|
||
|
|
<h3><a name="customizing"></a>Customizing tolua++</h3>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<b>tolua++</b> calls empty functions at specific points of its execution. This functions
|
||
|
|
can be redefined on a separate lua file (and included using the -L command line option)
|
||
|
|
and be used to control the way <b>tolua++</b> behaves. This is the list of functions
|
||
|
|
(taken from basic.lua on the <b>tolua++</b> source):
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<PRE>
|
||
|
|
|
||
|
|
-- called right after processing the $[ichl]file directives,
|
||
|
|
-- right before processing anything else
|
||
|
|
-- takes the package object as the parameter
|
||
|
|
function preprocess_hook(p)
|
||
|
|
-- p.code has all the input code from the pkg
|
||
|
|
end
|
||
|
|
|
||
|
|
|
||
|
|
-- called for every $ifile directive
|
||
|
|
-- takes a table with a string called 'code' inside, the filename, and any extra arguments
|
||
|
|
-- passed to $ifile. no return value
|
||
|
|
function include_file_hook(t, filename, ...)
|
||
|
|
|
||
|
|
end
|
||
|
|
|
||
|
|
-- called after processing anything that's not code (like '$renaming', comments, etc)
|
||
|
|
-- and right before parsing the actual code.
|
||
|
|
-- takes the Package object with all the code on the 'code' key. no return value
|
||
|
|
function preparse_hook(package)
|
||
|
|
|
||
|
|
end
|
||
|
|
|
||
|
|
|
||
|
|
-- called after writing all the output.
|
||
|
|
-- takes the Package object
|
||
|
|
function post_output_hook(package)
|
||
|
|
|
||
|
|
end
|
||
|
|
|
||
|
|
-- called at the beginning of the main parser function, with the code being parsed as a parameter
|
||
|
|
-- it can return nil if nothing was foind, or the contents of 'code', modified by the function
|
||
|
|
-- Usually a parser hook will search the beginning of the string for a token, and if it finds
|
||
|
|
-- anything, return the string without that token (after doing whatever it has to do with the token).
|
||
|
|
function parser_hook(code)
|
||
|
|
|
||
|
|
end
|
||
|
|
|
||
|
|
|
||
|
|
-- called from classFunction:supcode, before the call to the function is output
|
||
|
|
-- the classFunction object is passed.
|
||
|
|
function pre_call_hook(f)
|
||
|
|
|
||
|
|
end
|
||
|
|
|
||
|
|
-- called from classFunction:supcode, after the call to the function is output
|
||
|
|
-- the classFunction object is passed.
|
||
|
|
function post_call_hook(f)
|
||
|
|
|
||
|
|
end
|
||
|
|
|
||
|
|
-- called before the register code is output
|
||
|
|
function pre_register_hook(package)
|
||
|
|
|
||
|
|
end
|
||
|
|
|
||
|
|
-- called to output an error message
|
||
|
|
function output_error_hook(...)
|
||
|
|
return string.format(...)
|
||
|
|
end
|
||
|
|
|
||
|
|
|
||
|
|
</PRE>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<h4>Handling custom types</h4>
|
||
|
|
|
||
|
|
Starting from version 1.0.93, it is possible to specify custom functions to handle certain types. There are 3
|
||
|
|
types of functions: a <tt>'push function'</tt>, used to push the C value onto the Lua stack, a <tt>'to function'</tt>,
|
||
|
|
used to retrieve the value from the Lua stack, and return it as a C value, and an <tt>'is function'</tt>, used to
|
||
|
|
check if the value on the stack is valid (or convertible to a C value by the <tt>to function</tt>). These functions are modelled upon
|
||
|
|
<tt>tolua_pushusertype</tt>, <tt>tolua_tousertype</tt> and <tt>tolua_isusertype</tt>, declared in <tt>tolua++.h</tt>.
|
||
|
|
<p>
|
||
|
|
A number of arrays found in <tt>basic.lua</tt> are used to specify these functions:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<PRE>
|
||
|
|
-- for specific types
|
||
|
|
_push_functions = {}
|
||
|
|
_is_functions = {}
|
||
|
|
_to_functions = {}
|
||
|
|
|
||
|
|
-- for base types
|
||
|
|
_base_push_functions = {}
|
||
|
|
_base_is_functions = {}
|
||
|
|
_base_to_functions = {}
|
||
|
|
</PRE>
|
||
|
|
|
||
|
|
<b>Example (using the -L command line option):</b>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<PRE>
|
||
|
|
_is_functions['Vector3'] = 'custom_is_vector3' -- checks for a 3d vector
|
||
|
|
-- (either userdata, or a table with 3 values)
|
||
|
|
_to_functions['Vector3'] = 'custom_to_vector3' -- convertes the eventual table to a Vector3
|
||
|
|
|
||
|
|
_base_push_functions['Widget'] = 'custom_push_widget' -- pushes anything that inherits from Widget
|
||
|
|
</PRE>
|
||
|
|
|
||
|
|
The <tt>_base</tt> tables are used to lookup functions for types that are up in the inheritance chain.
|
||
|
|
|
||
|
|
<h4>Access</h4>
|
||
|
|
|
||
|
|
Starting from version 1.0.7, all objects have a an <tt>access</tt> flag, which determines the object's access
|
||
|
|
inside its container. Container objects also have a member called <tt>curr_member_access</tt>, which determines
|
||
|
|
the access of each child object at the moment of its addition to the container. If the <tt>access</tt> flag has
|
||
|
|
the value <tt>nil</tt> (default), <tt>false</tt> or <tt>0</tt>, the object is public. Otherwise, the object
|
||
|
|
is not public, and <b>tolua++</b> will not export any code for that object (and any objects it may contain).
|
||
|
|
<p>
|
||
|
|
|
||
|
|
Another 'interesting' function is <tt>extract_code</tt>, defined on basic.lua, which
|
||
|
|
extracs the code from files included with $cfile and $hfile (by looking for tolua_begin/end and tolua_export).
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<h3><a name="compatibility"></a>Compatibility with older versions.</h3>
|
||
|
|
|
||
|
|
<h4>tolua++ <1.0.90</h4>
|
||
|
|
<p>
|
||
|
|
Version 1.0.90 of <b>tolua++</b> introduces 2 small API changes the might be incompatible
|
||
|
|
with older versions on some cases:
|
||
|
|
<p>
|
||
|
|
<b>TEMPLATE_BIND</b>
|
||
|
|
<p>
|
||
|
|
<tt>TEMPLATE_BIND</tt> is deprecated. Use <tt>TOLUA_TEMPLATE_BIND</tt> instead. Also, when
|
||
|
|
declaring a template, the <tt>TOLUA_TEMPLATE_BIND</tt> statement has to be the first thing
|
||
|
|
inside the class declaration, otherwise it will be ignored. This fixes a possible problem
|
||
|
|
with nested template declarations.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<b>Retrieving Objects</b>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
When passing a full userdata to a function that accepts light userdata parameters (void*),
|
||
|
|
the <b>tolua++</b> library function <tt>tolua_touserdata</tt> will detect the full userdata and dereference
|
||
|
|
the void** pointer if necesary. This is a change on the function's behaviour (which used to return the pointer as-is). This allows us to pass pointers to objects to a function that accepts
|
||
|
|
void* pointers. Note that this was a problem when switching from <b>toLua</b> version 4 to version 5 (and <b>tolua++</b> versions < 1.0.90).
|
||
|
|
|
||
|
|
<h4>toLua 4</h4>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<b>Retrieving Objects</b>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
Users switching from <b>tolua</b> v4 should know that <b>tolua++</b> stores the objects as
|
||
|
|
<tt>void**</tt> on Lua, so when retrieving an object from the luastate using <tt>lua_touserdata</tt>,
|
||
|
|
the pointer should be dereferenced. The library function <tt>tolua_tousertype</tt>
|
||
|
|
should work as expected. Example:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<pre>
|
||
|
|
lua_pushglobal(lua_state, "get_Object");
|
||
|
|
lua_call(lua_state, 0, 1); // calling a function that returns an Object
|
||
|
|
|
||
|
|
Object *new_object = (Object*)(*lua_touserdata(lua_state, -1));
|
||
|
|
<i>or</i>
|
||
|
|
Object *new_object = (Object*)tolua_tousertype(lua_state, -1, NULL);
|
||
|
|
</pre>
|
||
|
|
|
||
|
|
<b>C++ Strings</b>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<b>tolua++</b> binds the c++ type <tt>std::string</tt> as a basic type, passing it
|
||
|
|
to Lua as a regular string (using the method <tt>c_str()</tt>). This feature can be
|
||
|
|
turned off with the command line option <tt>-S</tt>.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<b>Operators</b>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
The list of supported operators has changed, see <a href="#classes">Binding classes and methods</a>
|
||
|
|
for more information.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<h4>toLua 5</h4>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<b>Class destructors.</b>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
With every class constructor, <b>tolua++</b> exports a 'local' constructor, to create an instance
|
||
|
|
of the class that is owned by the lua state. To implement this, <b>tolua++</b> will also export
|
||
|
|
a function that will <tt>delete</tt> the class. There are 2 options to prevent this:
|
||
|
|
<p>
|
||
|
|
|
||
|
|
Using the <b>-D</b> command line option will turn this off completely. Destructor functions will
|
||
|
|
only be exported when a destructor for the class is explicitly declared, or when there is a function
|
||
|
|
or method that returns an object of the type by value (this is compatible with <b>tolua</b>'s behaviour).
|
||
|
|
<p>
|
||
|
|
|
||
|
|
Using the <tt>TOLUA_PROTECTED_DESTRUCTOR</tt> directive inside the class declaration, to specify that the
|
||
|
|
class has a private or protected destructor. In this case, no destructor will be exported for that class.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<b><tt>operator[]</tt> index</b>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
Users switching from <b>tolua</b> v5 should know that <b>tolua</b> 5 substracts 1
|
||
|
|
from the index on operator[] functions, for compatibility with lua's method for indexing arrays
|
||
|
|
(1 is the first element). This feature is turned off by default on <b>tolua++</b>
|
||
|
|
(making it compatible with <b>tolua</b> 4). It can be turned back on with the
|
||
|
|
command line option <tt>-1</tt>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<b>C++ Strings</b>
|
||
|
|
<p>
|
||
|
|
|
||
|
|
(see c++ strings on <b>tolua</b> 4 below)
|
||
|
|
|
||
|
|
|
||
|
|
<H3>
|
||
|
|
<A NAME="changes-v30"></A>Changes since v. 3.0</H3>
|
||
|
|
|
||
|
|
<ul>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Support for binding arrays as variables and struct/class fields;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Support for embedding Lua code into the generated binding code;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
New utility functions: <I>cast</I> and <I>takeownership</I>;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Option to create the corresponding header file of the binding code;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
New "close" package function;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Fixed bug on cloning objects in C++;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Fixed bug on enum and struct parsing;</LI>
|
||
|
|
</ul>
|
||
|
|
<H3>
|
||
|
|
<A NAME="changes-v2"></A>Changes since v. 2.0</H3>
|
||
|
|
<ul>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
There is a new executable parser;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Support for multiple Lua states is provided;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Support for module definition is provided;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Global variables is now directly bound to Lua global variables;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Constness of user defined types is preserved in Lua;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Support for multiple returned values from C/C++ is provided (simulating
|
||
|
|
parameters passed by reference);</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Constants, variables, and functions bound to Lua can have different names
|
||
|
|
from their C/C++ counterparts;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Object-oriented framework (and other utility functions) used in <B>tolua
|
||
|
|
</B>is
|
||
|
|
now exported for Lua programmers;</LI>
|
||
|
|
|
||
|
|
<H4>
|
||
|
|
Incompatibilities</H4>
|
||
|
|
Lua code based on <B>tolua</B> v2.* should run with no change on <B>tolua
|
||
|
|
</B>v3.0.
|
||
|
|
Although, it may be necessary to change the .pkg file in order to get the
|
||
|
|
same behavior. The following incompatibilities exist:
|
||
|
|
<UL>
|
||
|
|
<LI>
|
||
|
|
Parameters defined as pointer to basic types are no longer converted to
|
||
|
|
arrays of dimension one; they are now considered parameters passed by reference.</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Automatic initialization for C++ code must be explicitly requested when
|
||
|
|
using the new parser;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Global variables are no longer mapped to a table; the definition of a module
|
||
|
|
including the global variables may be used to simulate the old behavior;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
The initialization function is no longer toLua_<I>package</I>_open but
|
||
|
|
tolua_<I>package</I>_open, without the capital letter (sorry!).</LI>
|
||
|
|
</UL>
|
||
|
|
</ul>
|
||
|
|
<H3>
|
||
|
|
<A NAME="changes-v1"></A>Changes since v. 1.*</H3>
|
||
|
|
|
||
|
|
<ul>
|
||
|
|
<LI>
|
||
|
|
The binding code should run much faster;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
The <I>cleaned header file </I>extension should now be <TT>.pkg</TT> instead
|
||
|
|
of <TT>.L</TT>;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Type modifiers is now accepted (though the current version ignores
|
||
|
|
<TT>const</TT>'s);</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Returning object by value is accepted and memory allocation is controlled
|
||
|
|
by Lua garbage collection;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Overloaded functions/methods are accepted;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Parameters with default values are accepted;</LI>
|
||
|
|
|
||
|
|
<LI>
|
||
|
|
Some overloaded operators are automatically bound.</LI>
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
<H3>
|
||
|
|
<A NAME="credits"></A>Credits</H3>
|
||
|
|
Luiz Henrique de Figueiredo had the idea of creating a tool to automatically
|
||
|
|
bind C code to Lua. L.H.F. wrote the very first version of such a tool
|
||
|
|
(that bound C functions, variables, and constants) in <I>awk</I>. At that
|
||
|
|
time, Waldemar Celes (now the main author) was only responsible for the C code that supported the generated
|
||
|
|
binding code.
|
||
|
|
<p>
|
||
|
|
While working at NGD Studios, Ariel Manzur made some changes to tolua4 for their
|
||
|
|
game engine. After the release of tolua5, having left NGD, enough changes were
|
||
|
|
made to tolua to justify a separate release (with Waldemar's blessing :-)
|
||
|
|
<BR>
|
||
|
|
<H3>
|
||
|
|
<A NAME="availability"></A><B>Availability</B></H3>
|
||
|
|
<B>tolua++ </B>is freely available by <A HREF="http://www.codenix.com/~tolua/tolua++-current.tar.bz2">http</A>.
|
||
|
|
The software provided hereunder is on an "as is" basis, and the author
|
||
|
|
has no obligation to provide maintenance, support, updates, enhancements,
|
||
|
|
or modifications.
|
||
|
|
<P>
|
||
|
|
<HR WIDTH="100%">This document was created by <A HREF="http://www.tecgraf.puc-rio.br/~celes/">Waldemar Celes</A>
|
||
|
|
With modifications by <a href="http://www.codenix.com/index.php?section=contact">Ariel Manzur</a>/
|
||
|
|
<BR>Last update: Sept 2003<BODT>
|
||
|
|
</BODY>
|
||
|
|
</HTML>
|