currentline
if (ar.currentline > 0)
lua_pushfstring(L, "%d:", ar.currentline);
if (ar.currentline > 0) { /* is there info? */
lua_pushfstring(L, "%s:%d: ", ar.short_src, ar.currentline);
ar->currentline = (ci && isLua(ci)) ? currentline(ci) : -1;
int line = currentline(ci);
ar.currentline = line;
int currentline; /* (l) */