Re: Eval a Lua expression

[Shmuel Zeigerman <shmuz@...>]

Eugen-Andrei Gavriloaie wrote:
> Is there a method of evaluating an 
> expression in the present lua context? Here is what I want:
>
> lua_evaluate_expression(L,"applications[2].type"); // expect to find 
> `mysql` string pushed into the stack after this call
>
> or
>
> lua_evaluate_expression(L,"#applications"); // expect to find value of 2 
> pushed into the stack after this call
>
> This is supposed to push the result of the expression into the stack. 

The following is not very efficient, but seems to do what you want
(not tested; error checks to be added):

void lua_evaluate_expression(lua_State *L, const char *expr) {
  lua_pushfstring(L, "return %s", expr);
  luaL_loadstring(L, lua_tostring(L,-1));
  lua_remove(L,-2);
  lua_pcall(L,0,1,0);
}

--
Shmuel