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/* Should be a Lua skang module, roughly the same as test.lua
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')
// push_lua(L, "@ @ $ $ & $", skang, "thingasm", LUA_REGISTRYINDEX, ourName, "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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