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/* Should be a Lua skang module, roughly the same as test.lua
TODO - See if this still works if it's an app instead of a library.
I think the problem will be duplicate Lua library names.
The C app will be linked to one copy, the lua executable that require() this is linked to another, even if it's the same one.
Much hilarity ensues.
Not to mention linker flags being different.
Plan B -
Widget skang module runs the window app, and sends stuff to it.
Seems to be several problems with linking in various OSes, here's some
possibly helpful links -
http://lua.2524044.n2.nabble.com/C-Lua-modules-not-compatible-with-every-Lua-interpreter-td7647522.html
http://lua-users.org/wiki/LuaProxyDllFour
http://stackoverflow.com/questions/11492194/how-do-you-create-a-lua-plugin-that-calls-the-c-lua-api?rq=1
http://lua-users.org/lists/lua-l/2008-01/msg00671.html
*/
#include <lua.h>
#include <lauxlib.h>
static const char *ourName = "test_c";
int skang, _M;
static int cfunc (lua_State *L)
{
double arg1 = luaL_checknumber(L, 1);
const char *arg2 = luaL_checkstring(L, 2);
printf("Inside %s.cfunc(%f, %s)\n", ourName, arg1, arg2);
return 0;
}
static void dumpStack(lua_State *L, int i)
{
int type = lua_type(L, i);
switch (type)
{
case LUA_TNONE : printf("Stack %d is empty\n", i); break;
case LUA_TNIL : printf("Stack %d is a nil\n", i); break;
case LUA_TBOOLEAN : printf("Stack %d is a boolean\n", i); break;
case LUA_TNUMBER : printf("Stack %d is a number\n", i); break;
case LUA_TSTRING : printf("Stack %d is a string - %s\n", i, lua_tostring(L, i)); break;
case LUA_TFUNCTION : printf("Stack %d is a function\n", i); break;
case LUA_TTHREAD : printf("Stack %d is a thread\n", i); break;
case LUA_TTABLE : printf("Stack %d is a table\n", i); break;
case LUA_TUSERDATA : printf("Stack %d is a userdata\n", i); break;
case LUA_TLIGHTUSERDATA : printf("Stack %d is a light userdata\n", i); break;
default : printf("Stack %d is unknown\n", i); break;
}
}
/* local test_c = require 'test_c'
Lua's require() function will strip any stuff from the front of the name
separated by a hyphen, so 'ClientHamr-GuiLua-test_c' -> 'test_c'. Then
it will search through a path, and eventually find this test_c.so (or
test_c.dll or whatever), then call luaopen_test_c(), which should return
a table. The argument (only thing on the stack) for this function will
be 'test_c'.
Normally luaL_register() creates a table of functions, that is the table
returned, but we want to do something different with skang.
*/
int luaopen_test_c(lua_State *L)
{
lua_Number i;
// In theory, the only thing on the stack now is 'test_c' from the require() call.
// pseudo-indices, special tables that can be accessed like the stack -
// LUA_GLOBALSINDEX - thread environment, where globals are
// LUA_ENVIRONINDEX - C function environment, in this case luaopen_test_c() is the C function
// LUA_REGISTRYINDEX - C registry, global, for unique keys use the module name as a string, or a lightuserdata address to a C object in our module.
// lua_upvalueindex(n) - C function upvalues
// The only locals we care about are skang and _M.
// All modules go into package.loaded[name] as well.
// skang is essentially a global anyway.
// _M we pass back as the result, and our functions get added to it by skang.thingasm()
// Not entirely true, _M is a proxy table, getmetatable(_M).__values[cfunc] would be our function.
// local skang = require 'skang'
lua_getglobal(L, "require");
lua_pushstring(L, "skang");
lua_call(L, 1, 1);
skang = lua_gettop(L);
// dumpStack(L, skang);
// local _M = skang.moduleBegin('test_c', nil, 'Copyright 2014 David Seikel', '0.1', '2014-03-27 03:57:00', nil, false)
lua_getfield(L, skang, "moduleBegin");
lua_pushstring(L, ourName);
lua_pushnil(L); // Author comes from copyright.
lua_pushstring(L, "Copyright 2014 David Seikel");
lua_pushstring(L, "0.1");
lua_pushstring(L, "2014-03-27 03:57:00");
lua_pushnil(L); // No skin.
lua_pushboolean(L, 0); // We are not a Lua module.
lua_call(L, 7, 1); // call 'skang.moduleBegin' with 7 arguments and 1 result.
_M = lua_gettop(L);
// dumpStack(L, _M);
// At this point the stack should be - 'test_c', skang, _M. Let's test that.
/*
int top = 0, j;
top = lua_gettop(L);
printf("MODULE test_c has %d stack items.\n", top);
for (j = 1; j <= top; j++)
dumpStack(L, j);
*/
// Save this module in the C registry.
lua_setfield(L, LUA_REGISTRYINDEX, ourName);
// TODO - This is too verbose. I've had an idea for writing some sort of generic wrapper, though others have done the same.
// http://www.lua.org/pil/25.3.html seems the most reasonable of the examples I've found.
// On the other hand, the generic argument pulling / pushing stuff I did for edje_lua2 gets us half way there.
// This uses function{} style.
// skang.thingasm{_M, 'cfooble,c', 'cfooble help text', 1, widget=\"'edit', 'The cfooble:', 1, 1, 10, 50\", required=true}
lua_getfield(L, skang, "thingasm");
i = 1;
lua_newtable(L);
lua_pushnumber(L, i++);
lua_getfield(L, LUA_REGISTRYINDEX, ourName); // Coz getfenv() can't find C environment.
lua_settable(L, -3);
lua_pushnumber(L, i++);
lua_pushstring(L, "cfooble,c");
lua_settable(L, -3);
lua_pushnumber(L, i++);
lua_pushstring(L, "cfooble help text");
lua_settable(L, -3);
lua_pushnumber(L, i++);
lua_pushnumber(L, 1);
lua_settable(L, -3);
lua_pushstring(L, "'edit', 'The cfooble:', 1, 1, 10, 50");
lua_setfield(L, -2, "widget");
lua_pushboolean(L, 1); // Is required.
lua_setfield(L, -2, "required");
lua_call(L, 1, 0);
// skang.thing(_M, 'cbar', 'Help text', 'Default')
lua_getfield(L, skang, "thingasm");
lua_getfield(L, LUA_REGISTRYINDEX, ourName); // Coz getfenv() can't find C environment.
lua_pushstring(L, "cbar");
lua_pushstring(L, "Help text");
lua_pushstring(L, "Default");
lua_call(L, 4, 0);
// skang.thingasm(_M, 'cfoo')
lua_getfield(L, skang, "thingasm");
lua_getfield(L, LUA_REGISTRYINDEX, ourName); // Coz getfenv() can't find C environment.
lua_pushstring(L, "cfoo");
lua_call(L, 2, 0);
// skang.thingasm(_M, 'cfunc', 'cfunc does nothing really', cfunc, 'number,string')
lua_getfield(L, skang, "thingasm");
lua_getfield(L, LUA_REGISTRYINDEX, ourName); // Coz getfenv() can't find C environment.
lua_pushstring(L, "cfunc");
lua_pushstring(L, "cfunc does nothing really");
lua_pushcfunction(L, cfunc);
lua_pushstring(L, "number,string");
lua_call(L, 5, 0);
// skang.moduleEnd(_M)
lua_getfield(L, skang, "moduleEnd");
lua_getfield(L, LUA_REGISTRYINDEX, ourName);
// TODO - This should be (L, 1, 0), but that makes test.lua fail, claiming that none of the Things got added. WTF?
lua_call(L, 1, 1);
int top = 0, j;
top = lua_gettop(L);
printf("MODULE test_c has %d stack items.\n", top);
for (j = 1; j <= top; j++)
dumpStack(L, j);
return 1;
}
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