/* File : example.i */
/*
This demonstrates how to pass a lua function, into some C code and then call it.
There are two examples, the first is as a parameter, the second as a global variable.
*/
%module example
%{
#include "example.h"
%}
/* the extra wrappers for lua functions, see SWIG/Lib/lua/lua_fnptr.i for more details */
%include "lua_fnptr.i"
/* these are a bunch of C functions which we want to be able to call from lua */
extern int add(int,int);
extern int sub(int,int);
extern int mul(int,int);
/* this function takes a lua function as a parameter and calls it.
As this is takes a lua fn it needs lua code
*/
%inline %{
int callback(int a, int b, SWIGLUA_FN fn)
{
SWIGLUA_FN_GET(fn);
lua_pushnumber(fn.L,a);
lua_pushnumber(fn.L,b);
lua_call(fn.L,2,1); /* 2 in, 1 out */
return (int)luaL_checknumber(fn.L,-1);
}
%}
/******************
Second code uses a stored reference.
*******************/
%inline %{
/* note: this is not so good to just have it as a raw ref
people could set anything to this
a better solution would to be to have a fn which wants a SWIGLUA_FN, then
checks the type & converts to a SWIGLUA_REF.
*/
SWIGLUA_REF the_func={0,0};
void call_the_func(int a)
{
int i;
if (the_func.L==0){
printf("the_func is zero\n");
return;
}
swiglua_ref_get(&the_func);
if (!lua_isfunction(the_func.L,-1))
{
printf("the_func is not a function\n");
return;
}
lua_pop(the_func.L,1); /* tidy stack */
for(i=0;i<a;i++)
{
swiglua_ref_get(&the_func);
lua_pushnumber(the_func.L,i);
lua_call(the_func.L,1,0); /* 1 in, 0 out */
}
}
%}
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