Re: How to locate the implementation of a specific function, e.g. string.byte?

[Francisco Olarte <folarte@...>]

Hi Sunshilong:
On Sat, Oct 10, 2020 at 9:47 AM 孙世龙 sunshilong <sunshilong369@gmail.com> wrote:
> How to locate the implementation of a specific function, e.g. string.byte?
> I hope to dig deep in the related code snippet.
> I would be grateful to have some help with this question.

Source code is pretty easy to follow. Normally functions are
registered  in src/l*lib.c. You can start by grepping for
luaL_setfuncs, which is the function most normally used to register
them, and find things like ( in 5.4.0 sources )

src/lstrlib.c
1786:  luaL_setfuncs(L, stringmetamethods, 0);

Then you can go there and see:

   1761 static const luaL_Reg strlib[] = {
   1762   {"byte", str_byte},
   1763   {"char", str_char},

And from these is just a matter of searching for it:

    176 static int str_byte (lua_State *L) {
    177   size_t l;
    178   const char *s = luaL_checklstring(L, 1, &l);

This method works generally for me when I'm curious on how a lib
function is done.

Francisco Olarte.