(SWIG / Lua) How to access base / parent class list in swig_lua_class
I noticed that in the generated SWIG wrappers for a given set of classes, SWIG keeps a list of C string representations of all parent classes from which this class inherits. (char ** base_names). I know there is a function
swig_type(some_variable)
which will return the string representation of the given data type of the variable. Is there a function that will return the parent class table as strings? If not, is there an easy way to write this function? I am not entirely familiar with the inner workings of SWIG.
Thanks!
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1 answer
Something like this should work (not tested since I am not using SWIG with Lua):
// insert into runtime section
// this is the C function that iterates over the base_names array
// (I'm assuming that the array is terminated with a NULL)
%runtime %{
/* lua callable function to get the userdata type */
SWIGRUNTIME int SWIG_Lua_basenames(lua_State* L)
{
swig_lua_userdata* usr;
swig_lua_class* clss = NULL;
int i = 0;
if (lua_isuserdata(L,1))
{
usr=(swig_lua_userdata*)lua_touserdata(L,1); /* get data */
if (usr && usr->type && usr->type->clientdata) {
// fetch the swig_lua_class struct, it contains the base_names
clss = (swig_lua_class*)usr->type->clientdata;
}
}
/* create a new table with all class base names in it
note that I create it even if clss is NULL, that way
an empty table -should- be returned
*/
lua_newtable(L);
while(clss && clss->base_names[i]) {
lua_pushnumber(L, i+1); /* lua tables are 1-indexed */
lua_pushstring(L, clss->base_names[i]);
lua_rawset(L, -3);
i++;
}
return 1;
}
%}
%init %{
/* this goes into the user init function, register our new function with
Lua runtime
*/
SWIG_Lua_add_function(L,"swig_base_names",SWIG_Lua_basenames);
%}
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