Script might well override a static map, but can't risk it not doing it, and preview completely failing. Better to just not try it for static maps. Some script cfg might help. Could also avoid unnnecessary preview regenerations even if the script was doing nothing at all.
/*
** $Id: lstring.h,v 1.43.1.1 2007/12/27 13:02:25 roberto Exp $
** String table (keep all strings handled by Lua)
** See Copyright Notice in lua.h
*/
#ifndef lstring_h
#define lstring_h
#include "lgc.h"
#include "lobject.h"
#include "lstate.h"
#define sizestring(s) (sizeof(union TString)+((s)->len+1)*sizeof(char))
#define sizeudata(u) (sizeof(union Udata)+(u)->len)
#define luaS_new(L, s) (luaS_newlstr(L, s, strlen(s)))
#define luaS_newliteral(L, s) (luaS_newlstr(L, "" s, \
(sizeof(s)/sizeof(char))-1))
#define luaS_fix(s) l_setbit((s)->tsv.marked, FIXEDBIT)
LUAI_FUNC void luaS_resize (lua_State *L, int newsize);
LUAI_FUNC Udata *luaS_newudata (lua_State *L, size_t s, Table *e);
LUAI_FUNC TString *luaS_newlstr (lua_State *L, const char *str, size_t l);
#endif