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On 7-Aug-05, at 12:18 PM, Uli Kusterer wrote:

In particular, how likely is the compiled file format to change again? It would be rather handy if I could ship compiled scripts because they wouldn't be as readable as plain text.

I would guess that the compiled file format is likely to change (at least a little bit) with every release. Backwards compatibility of bytecode is not a priority (nor should it be imho). The API is fairly stable, but minor changes do occur, so you are likely to need to recompile extensions for a new version anyway; adding a step to compile byte code for the new version is not much more difficult if you have a decent make tool.

Byte code is not completely platform-independent, in any event, and it has been suggested that it may become even less platform-independent in the future. One way to distribute Lua programs as part of an application is to simply include the Lua source code in a file:

/* This is *not* the 5.1 module style, but it works with 5.0.2 */
const char[] mylib =
 "mylib = {} \n"
 "function mylib.frobnicate(x) ... end \n"
 "function mylib.defrobnicate(x) ... end \n"
 "return mylib \n"

int luaopen_mylib (lua_State *L) {
  if (luaL_loadbuffer(L, prog, sizeof(mylib)-1, "mylib")
      || lua_pcall(L, 1, 0)) {
    // for debugging, use: lua_error(L, 1)
    fprintf(stderr, "Mysterious error at startup\n");
  return 1;

If you want to obscure the source code more than that, gzip it before inserting it into the C source, and use zlib to decompress it before calling luaL_loadbuffer, or write a little decompressing string loader and use lua_load. (I don't think this is a very good way of hiding your code; it is only effective against stupid people without smart friends :) But it does reduce executable size if the scripts are large.)