Function luaD_tryfuncTM

xrepo/packages/l/lua/port/lua/src/ldo.c:390–402

** Check whether 'func' has a '__call' metafield. If so, put it in the ** stack, below original 'func', so that 'luaD_precall' can call it. Raise ** an error if there is no '__call' metafield. */

** an error if there is no '__call' metafield.
*/
StkId luaD_tryfuncTM (lua_State *L, StkId func) {
  const TValue *tm;
  StkId p;
  checkstackGCp(L, 1, func);  /* space for metamethod */
  tm = luaT_gettmbyobj(L, s2v(func), TM_CALL);  /* (after previous GC) */
  if (l_unlikely(ttisnil(tm)))
    luaG_callerror(L, s2v(func));  /* nothing to call */
  for (p = L->top; p > func; p--)  /* open space for metamethod */
    setobjs2s(L, p, p-1);
  L->top++;  /* stack space pre-allocated by the caller */
  setobj2s(L, func, tm);  /* metamethod is the new function to be called */
  return func;
}


/*