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[lua] Added a typemap DISOWN for SWIGTYPE* and SWIGTYPE[], and support for %delobject feature.

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git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@10326 626c5289-ae23-0410-ae9c-e8d60b6d4f22
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Mark Gossage 2008-03-27 01:58:30 +00:00
commit 11647d87e8
14 changed files with 377 additions and 19 deletions
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33
Doc/Manual/Lua.html
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@ -980,10 +980,32 @@ stack traceback:
</pre></div>
<p>
And similarly for numeric types, enums, chars, char*'s and std::string's.
If you want to catch an exception, you must use either pcall() or xpcall(), which are documented in the Lua manual.
Using xpcall will allow you to obtain additional debug information (such as a stacktrace).
</p>
<div class="targetlang"><pre>
> function a() b() end -- function a() calls function b()
> function b() message() end -- function b() calls C++ function message(), which throws
> ok,res=pcall(a) -- call the function
> print(ok,res)
false I died.
> ok,res=xpcall(a,debug.traceback) -- call the function
> print(ok,res)
false I died.
stack traceback:
[C]: in function 'message'
runme.lua:70: in function 'b'
runme.lua:67: in function &lt;runme.lua:66&gt;
[C]: in function 'xpcall'
runme.lua:95: in main chunk
[C]: ?
</pre></div>
<p>
However its not so simple for objects. Thrown objects are not valid outside the 'catch' block. Therefore they cannot be
SWIG is able to throw numeric types, enums, chars, char*'s and std::string's without problem.
However its not so simple for to throw objects.
Thrown objects are not valid outside the 'catch' block. Therefore they cannot be
returned to the interpreter.
The obvious ways to overcome this would be to either return a copy of the object, or so convert the object to a string and
return that. Though it seems obvious to perform the former, in some cases this is not possible, most notably when
@ -1013,7 +1035,7 @@ stack traceback:
</pre></div>
<p>
To get a more useful behaviour out of SWIG you must either: provide a way to convert your exceptions into strings, or
only throw objects which can be copied.
throw objects which can be copied.
</p>
<p>
SWIG has typemaps for std::exception and its children already written, so a function which throws any of these will
@ -1025,7 +1047,7 @@ If you have your own class which you want output as a string you will need to ad
<div class="code"><pre>
%typemap(throws) my_except
%{
lua_pushstring(L,$1.what()); // assuming what() returns a const char* message
lua_pushstring(L,$1.what()); // assuming my_except::what() returns a const char* message
SWIG_fail; // trigger the error handler
%}
</pre></div>
@ -1063,6 +1085,7 @@ userdata: 0003D880
42 Hosed
>
</pre></div>
<p>
Note: is is also possible (though tedious) to have a function throw several different kinds of exceptions. To process this
will require a pcall, followed by a set of if statements checking the type of the error.
@ -1129,7 +1152,7 @@ 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.
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>