lua2c.lua

local fs = require "bee.filesystem"

local code_main <const> = [[
#include <lua.hpp>

static int push_preload_table(lua_State *L);

static int searcher(lua_State *L) {
    const char *name = luaL_checkstring(L, 1);
    lua_pushvalue(L, 1);
    if (LUA_TNIL == lua_rawget(L, lua_upvalueindex(1))) {
        lua_pushfstring(L, "no module '%s'", name);
        return 1;
    }
    lua_call(L, 0, 1);
    const char* str = lua_tostring(L, -1);
    lua_Unsigned len = lua_rawlen(L, -1);
    if (luaL_loadbuffer(L, str, (size_t)len, str) == LUA_OK) {
        lua_pushstring(L, name);
        return 2;
    }
    else {
        return luaL_error(L, "error loading module '%s':\n\t%s", name, lua_tostring(L, -1));
    }
}

static int push_searcher(lua_State *L) {
    push_preload_table(L);
    lua_pushcclosure(L, searcher, 1);
    return 1;
}

#define REG_SOURCE(module, name) \
	lua_pushlightuserdata(L, (void *)name); \
	lua_pushinteger(L, sizeof(name)); \
	lua_pushcclosure(L, get_string, 2); \
	lua_setfield(L, -2, module);

static int get_string(lua_State *L) {
	const char* str = (const char *)lua_touserdata(L, lua_upvalueindex(1));
	size_t len = (size_t)lua_tointeger(L, lua_upvalueindex(2));
	lua_pushlstring(L, str, len);
	return 1;
}
]]

local code_reg <const> = [[REG_SOURCE($module, $name)]]

local code_bin <const> = [[
static const unsigned char $name[] = {
	$bytes
};
]]

local code_push <const> = [[
static int push_preload_table(lua_State *L) {
    lua_createtable(L, 0, $num);
    $reg
    return 1;
}
]]

local function readall(path)
    local file <close> = assert(io.open(path, "rb"))
    return file:read "a"
end

local function compile(content, symbol)
    local count = 0
    local function tohex(c)
        local b = string.format("0x%02x,", c:byte())
        count = count + 1
        if count == 16 then
            b = b.."\n    "
            count = 0
        end
        return b
    end
    local func = assert(load(content, "@"..symbol))
    local bin = string.dump(func)
    return bin:gsub(".", tohex)
end

local function embed(file, list, content, symbol)
    local cpp_symbol = "luasrc_"..symbol:match("^(.+)%.lua$"):gsub("/", "_")
    list[#list+1] = code_reg:gsub("$(%w+)", {
        name = cpp_symbol,
        module = symbol:match("^(.+)%.lua$"):gsub("/", "."),
    })
    local output = code_bin:gsub("$(%w+)", {
        name = cpp_symbol,
        bytes = compile(content, symbol),
    })
    file:write(output)
    file:write "\n"
end

local file <close> = assert(io.open("test.cpp", "wb"))
do
    file:write(code_main)
    file:write "\n"
end

local list = {}
for path, status in fs.pairs_r "scripts" do
    if not status:is_directory() and path:extension() == ".lua" then
        local filename = path:string()
        local symbol = filename:sub(9)
        embed(file, list, readall(filename), symbol)
    end
end
embed(file, list, readall "main.lua", "main.lua")

do
    local output = code_push:gsub("$(%w+)", {
        num = #list,
        reg = table.concat(list, "\n    "),
    })
    file:write(output)
end