Question

I’m trying to debug a C/C++ application which uses Lua 5.1. At this stage it would be very useful to have a way of dumping a human-readable representation of the data on the Lua stack while debugging. I’ve found the function lua_getstack which looks like the right kind of thing, but I can’t find a way of invoking it through the LLDB command line and printing it as something human readable. Is there a better way of doing this?

Answer 1

You can use something like this and then call it from the debugger:

void lua_stackdump(lua_State *L) 
{
  int i;
  int top = lua_gettop(L);
  for (i = 1; i <= top; i++) { /* repeat for each level */
    int t = lua_type(L, i);
    switch (t) {
      case LUA_TSTRING: { /* strings */
         printf("’%s’\n", lua_tostring(L, i));
         break;
      }
      case LUA_TBOOLEAN: { /* booleans */
         printf(lua_toboolean(L, i) ? "true" : "false");
         break;
      }
      case LUA_TNUMBER: { /* numbers */
         printf("%g\n", lua_tonumber(L, i));
         break;
      }
      default: { /* other values */
         printf("%s\n", lua_typename(L, t));
         break;
      }
    }
  }
  printf("\n"); /* end the listing */
}