/* ** $Id: ltm.c,v 1.1 2003/02/09 21:30:32 dheck Exp $ ** Tag methods ** See Copyright Notice in lua.h */ #include #include #include "lua.h" #include "ldo.h" #include "lmem.h" #include "lobject.h" #include "lstate.h" #include "ltm.h" const char *const luaT_eventname[] = { /* ORDER TM */ "gettable", "settable", "index", "getglobal", "setglobal", "add", "sub", "mul", "div", "pow", "unm", "lt", "concat", "gc", "function", "le", "gt", "ge", /* deprecated options!! */ NULL }; static int findevent (const char *name) { int i; for (i=0; luaT_eventname[i]; i++) if (strcmp(luaT_eventname[i], name) == 0) return i; return -1; /* name not found */ } static int luaI_checkevent (lua_State *L, const char *name, int t) { int e = findevent(name); if (e >= TM_N) luaO_verror(L, "event `%.50s' is deprecated", name); if (e == TM_GC && t == LUA_TTABLE) luaO_verror(L, "event `gc' for tables is deprecated"); if (e < 0) luaO_verror(L, "`%.50s' is not a valid event name", name); return e; } /* events in LUA_TNIL are all allowed, since this is used as a * 'placeholder' for "default" fallbacks */ /* ORDER LUA_T, ORDER TM */ static const char luaT_validevents[NUM_TAGS][TM_N] = { {1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1}, /* LUA_TUSERDATA */ {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, /* LUA_TNIL */ {1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1}, /* LUA_TNUMBER */ {1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, /* LUA_TSTRING */ {0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1}, /* LUA_TTABLE */ {1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0} /* LUA_TFUNCTION */ }; int luaT_validevent (int t, int e) { /* ORDER LUA_T */ return (t >= NUM_TAGS) ? 1 : luaT_validevents[t][e]; } static void init_entry (lua_State *L, int tag) { int i; for (i=0; iTMtable[tag].collected = NULL; } void luaT_init (lua_State *L) { int t; luaM_growvector(L, L->TMtable, 0, NUM_TAGS, struct TM, "", MAX_INT); L->nblocks += NUM_TAGS*sizeof(struct TM); L->last_tag = NUM_TAGS-1; for (t=0; t<=L->last_tag; t++) init_entry(L, t); } LUA_API int lua_newtag (lua_State *L) { luaM_growvector(L, L->TMtable, L->last_tag, 1, struct TM, "tag table overflow", MAX_INT); L->nblocks += sizeof(struct TM); L->last_tag++; init_entry(L, L->last_tag); return L->last_tag; } static void checktag (lua_State *L, int tag) { if (!(0 <= tag && tag <= L->last_tag)) luaO_verror(L, "%d is not a valid tag", tag); } void luaT_realtag (lua_State *L, int tag) { if (!validtag(tag)) luaO_verror(L, "tag %d was not created by `newtag'", tag); } LUA_API int lua_copytagmethods (lua_State *L, int tagto, int tagfrom) { int e; checktag(L, tagto); checktag(L, tagfrom); for (e=0; eu.d.tag; case LUA_TTABLE: return hvalue(o)->htag; default: return t; } } LUA_API void lua_gettagmethod (lua_State *L, int t, const char *event) { int e; e = luaI_checkevent(L, event, t); checktag(L, t); if (luaT_validevent(t, e) && luaT_gettm(L, t, e)) { clvalue(L->top) = luaT_gettm(L, t, e); ttype(L->top) = LUA_TFUNCTION; } else ttype(L->top) = LUA_TNIL; incr_top; } LUA_API void lua_settagmethod (lua_State *L, int t, const char *event) { int e = luaI_checkevent(L, event, t); checktag(L, t); if (!luaT_validevent(t, e)) luaO_verror(L, "cannot change `%.20s' tag method for type `%.20s'%.20s", luaT_eventname[e], luaO_typenames[t], (t == LUA_TTABLE || t == LUA_TUSERDATA) ? " with default tag" : ""); switch (ttype(L->top - 1)) { case LUA_TNIL: luaT_gettm(L, t, e) = NULL; break; case LUA_TFUNCTION: luaT_gettm(L, t, e) = clvalue(L->top - 1); break; default: lua_error(L, "tag method must be a function (or nil)"); } L->top--; }