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1 /* |
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2 ** $Id: ltm.c,v 2.8.1.1 2007/12/27 13:02:25 roberto Exp $ |
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3 ** Tag methods |
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4 ** See Copyright Notice in lua.h |
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5 */ |
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6 |
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7 |
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8 #include <string.h> |
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9 |
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10 #define ltm_c |
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11 #define LUA_CORE |
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12 |
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13 #include "lua.h" |
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14 |
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15 #include "lobject.h" |
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16 #include "lstate.h" |
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17 #include "lstring.h" |
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18 #include "ltable.h" |
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19 #include "ltm.h" |
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20 |
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21 |
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22 |
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23 const char *const luaT_typenames[] = { |
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24 "nil", "boolean", "userdata", "number", |
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25 "string", "table", "function", "userdata", "thread", |
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26 "proto", "upval" |
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27 }; |
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28 |
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29 |
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30 void luaT_init (lua_State *L) { |
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31 static const char *const luaT_eventname[] = { /* ORDER TM */ |
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32 "__index", "__newindex", |
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33 "__gc", "__mode", "__eq", |
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34 "__add", "__sub", "__mul", "__div", "__mod", |
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35 "__pow", "__unm", "__len", "__lt", "__le", |
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36 "__concat", "__call" |
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37 }; |
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38 int i; |
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39 for (i=0; i<TM_N; i++) { |
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40 G(L)->tmname[i] = luaS_new(L, luaT_eventname[i]); |
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41 luaS_fix(G(L)->tmname[i]); /* never collect these names */ |
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42 } |
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43 } |
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44 |
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45 |
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46 /* |
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47 ** function to be used with macro "fasttm": optimized for absence of |
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48 ** tag methods |
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49 */ |
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50 const TValue *luaT_gettm (Table *events, TMS event, TString *ename) { |
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51 const TValue *tm = luaH_getstr(events, ename); |
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52 lua_assert(event <= TM_EQ); |
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53 if (ttisnil(tm)) { /* no tag method? */ |
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54 events->flags |= cast_byte(1u<<event); /* cache this fact */ |
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55 return NULL; |
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56 } |
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57 else return tm; |
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58 } |
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59 |
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60 |
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61 const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o, TMS event) { |
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62 Table *mt; |
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63 switch (ttype(o)) { |
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64 case LUA_TTABLE: |
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65 mt = hvalue(o)->metatable; |
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66 break; |
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67 case LUA_TUSERDATA: |
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68 mt = uvalue(o)->metatable; |
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69 break; |
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70 default: |
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71 mt = G(L)->mt[ttype(o)]; |
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72 } |
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73 return (mt ? luaH_getstr(mt, G(L)->tmname[event]) : luaO_nilobject); |
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74 } |
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75 |