mirror of https://github.com/lua/lua
no more assignment expressions (they don't fit in Lua...)
This commit is contained in:
Roberto Ierusalimschy
parent
0870a2d1d8
commit
2679461637
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@ -1,5 +1,5 @@
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/*
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** $Id: lopcodes.h,v 1.30 1999/03/04 21:15:50 roberto Exp roberto $
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** $Id: lopcodes.h,v 1.31 1999/03/05 21:16:07 roberto Exp roberto $
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** Opcodes for Lua virtual machine
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** See Copyright Notice in lua.h
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*/
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@ -26,7 +26,6 @@ TAILCALL,/* b c v_c...v_1 f (return) f(v1,...,v_c) */
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PUSHNIL,/* b - nil_0...nil_b */
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POP,/* b a_b...a_1 - */
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POPDUP,/* b v a_b...a_1 v */
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PUSHNUMBERW,/* w - (float)w */
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PUSHNUMBER,/* b - (float)b */
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@ -56,18 +55,13 @@ CREATEARRAYW,/* w - newarray(size = w) */
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CREATEARRAY,/* b - newarray(size = b) */
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SETLOCAL,/* b x - LOC[b]=x */
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SETLOCALDUP,/* b x x LOC[b]=x */
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SETGLOBALW,/* w x - VAR[CNST[w]]=x */
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SETGLOBAL,/* b x - VAR[CNST[b]]=x */
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SETGLOBALDUPW,/*w x x VAR[CNST[w]]=x */
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SETGLOBALDUP,/* b x x VAR[CNST[b]]=x */
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SETTABLEPOP,/* - v i t - t[i]=v */
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SETTABLEPOPDUP,/* - v i t v t[i]=v */
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SETTABLE,/* b v a_b...a_1 i t a_b...a_1 i t t[i]=v */
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SETTABLEDUP,/* b v a_b...a_1 i t v a_b...a_1 i t t[i]=v */
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SETLISTW,/* w c v_c...v_1 t t t[i+w*FPF]=v_i */
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SETLIST,/* b c v_c...v_1 t t t[i+b*FPF]=v_i */
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51
lparser.c
51
lparser.c
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@ -1,5 +1,5 @@
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/*
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** $Id: lparser.c,v 1.26 1999/03/04 21:17:26 roberto Exp roberto $
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** $Id: lparser.c,v 1.27 1999/03/05 21:16:07 roberto Exp roberto $
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** LL(1) Parser and code generator for Lua
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** See Copyright Notice in lua.h
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*/
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@ -99,7 +99,7 @@ typedef struct FuncState {
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/*
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** prototypes for non-terminal functions
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*/
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static int assignment (LexState *ls, vardesc *v, int nvars, OpCode *codes);
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static int assignment (LexState *ls, vardesc *v, int nvars);
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static int cond (LexState *ls);
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static int funcname (LexState *ls, vardesc *v);
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static int funcparams (LexState *ls, int slf);
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@ -114,7 +114,6 @@ static void chunk (LexState *ls);
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static void constructor (LexState *ls);
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static void decinit (LexState *ls, listdesc *d);
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static void exp0 (LexState *ls, vardesc *v);
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static void Gexp (LexState *ls, vardesc *v);
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static void exp1 (LexState *ls);
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static void exp2 (LexState *ls, vardesc *v);
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static void explist (LexState *ls, listdesc *e);
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@ -467,22 +466,16 @@ static void lua_pushvar (LexState *ls, vardesc *var) {
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}
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/* to be used by "storevar" and assignment */
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static OpCode set_pop[] = {SETLOCAL, SETGLOBAL, SETTABLEPOP, SETTABLE};
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static OpCode set_dup[] = {SETLOCALDUP, SETGLOBALDUP, SETTABLEPOPDUP,
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SETTABLEDUP};
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static void storevar (LexState *ls, vardesc *var, OpCode *codes) {
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static void storevar (LexState *ls, vardesc *var) {
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switch (var->k) {
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case VLOCAL:
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code_oparg(ls, codes[0], var->info, -1);
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code_oparg(ls, SETLOCAL, var->info, -1);
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break;
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case VGLOBAL:
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code_oparg(ls, codes[1], var->info, -1);
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code_oparg(ls, SETGLOBAL, var->info, -1);
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break;
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case VINDEXED:
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code_opcode(ls, codes[2], -3);
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code_opcode(ls, SETTABLEPOP, -3);
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break;
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default:
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LUA_INTERNALERROR("invalid var kind to store");
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@ -739,7 +732,7 @@ static int stat (LexState *ls) {
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next(ls);
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needself = funcname(ls, &v);
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body(ls, needself, line);
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storevar(ls, &v, set_pop);
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storevar(ls, &v);
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return 1;
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}
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@ -765,7 +758,7 @@ static int stat (LexState *ls) {
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close_exp(ls, v.info, 0);
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}
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else { /* stat -> ['%'] NAME assignment */
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int left = assignment(ls, &v, 1, set_pop);
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int left = assignment(ls, &v, 1);
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adjuststack(ls, left); /* remove eventual 'garbage' left on stack */
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}
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return 1;
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@ -948,19 +941,6 @@ static void exp0 (LexState *ls, vardesc *v) {
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}
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static void Gexp (LexState *ls, vardesc *v) {
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/* Gexp -> exp0 | assignment */
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exp0(ls, v);
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if (v->k != VEXP && (ls->token == '=' || ls->token == ',')) {
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int left = assignment(ls, v, 1, set_dup);
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deltastack(ls, 1); /* DUP operations push an extra value */
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if (left > 0)
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code_oparg(ls, POPDUP, left, -left);
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v->k = VEXP; v->info = 0; /* this expression is closed now */
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}
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}
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static void push (LexState *ls, stack_op *s, int op) {
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if (s->top >= MAXOPS)
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luaX_error(ls, "expression too complex");
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@ -1015,9 +995,9 @@ static void simpleexp (LexState *ls, vardesc *v, stack_op *s) {
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ifpart(ls, 1, ls->linenumber);
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break;
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case '(': /* simpleexp -> '(' Gexp ')' */
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case '(': /* simpleexp -> '(' exp0 ')' */
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next(ls);
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Gexp(ls, v);
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exp0(ls, v);
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check(ls, ')');
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return;
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@ -1239,7 +1219,7 @@ static void decinit (LexState *ls, listdesc *d) {
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}
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static int assignment (LexState *ls, vardesc *v, int nvars, OpCode *codes) {
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static int assignment (LexState *ls, vardesc *v, int nvars) {
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int left = 0;
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unloaddot(ls, v);
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if (ls->token == ',') { /* assignment -> ',' NAME assignment */
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@ -1248,7 +1228,7 @@ static int assignment (LexState *ls, vardesc *v, int nvars, OpCode *codes) {
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var_or_func(ls, &nv);
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if (nv.k == VEXP)
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luaX_error(ls, "syntax error");
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left = assignment(ls, &nv, nvars+1, set_pop);
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left = assignment(ls, &nv, nvars+1);
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}
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else { /* assignment -> '=' explist1 */
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listdesc d;
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@ -1258,15 +1238,16 @@ static int assignment (LexState *ls, vardesc *v, int nvars, OpCode *codes) {
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}
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if (v->k != VINDEXED || left+(nvars-1) == 0) {
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/* global/local var or indexed var without values in between */
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storevar(ls, v, codes);
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storevar(ls, v);
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}
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else { /* indexed var with values in between*/
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code_oparg(ls, codes[3], left+(nvars-1), -1);
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left += 2; /* table/index are not popped, because they aren't on top */
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code_oparg(ls, SETTABLE, left+(nvars-1), -1);
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left += 2; /* table&index are not popped, because they aren't on top */
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}
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return left;
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}
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static void constructor (LexState *ls) {
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/* constructor -> '{' part [';' part] '}' */
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int line = ls->linenumber;
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32
lvm.c
32
lvm.c
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@ -1,5 +1,5 @@
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/*
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** $Id: lvm.c,v 1.52 1999/03/04 21:15:50 roberto Exp roberto $
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** $Id: lvm.c,v 1.53 1999/03/05 21:16:07 roberto Exp roberto $
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** Lua virtual machine
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** See Copyright Notice in lua.h
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*/
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@ -356,11 +356,6 @@ StkId luaV_execute (Closure *cl, TProtoFunc *tf, StkId base) {
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S->top -= aux;
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break;
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case POPDUP: aux = *pc++;
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*(S->top-aux-1) = *(S->top-1);
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S->top -= aux;
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break;
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case PUSHNUMBERW: aux += highbyte(*pc++);
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case PUSHNUMBER: aux += *pc++;
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ttype(S->top) = LUA_T_NUMBER;
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@ -424,45 +419,20 @@ StkId luaV_execute (Closure *cl, TProtoFunc *tf, StkId base) {
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*((S->stack+base) + aux) = *(--S->top);
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break;
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case SETLOCALDUP: aux = *pc++;
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*((S->stack+base) + aux) = *(S->top-1);
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break;
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case SETGLOBALW: aux += highbyte(*pc++);
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case SETGLOBAL: aux += *pc++;
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luaV_setglobal(tsvalue(&consts[aux]));
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break;
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case SETGLOBALDUPW: aux += highbyte(*pc++);
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case SETGLOBALDUP: aux += *pc++;
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*S->top = *(S->top-1);
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S->top++;
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luaV_setglobal(tsvalue(&consts[aux]));
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break;
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case SETTABLEPOP:
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luaV_settable(S->top-3);
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S->top -= 2; /* pop table and index */
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break;
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case SETTABLEPOPDUP: {
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TObject temp = *(S->top-1);
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luaV_settable(S->top-3);
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S->top--; /* pop index (temp goes into "table" position) */
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*(S->top-1) = temp;
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break;
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}
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case SETTABLE:
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luaV_settable(S->top-3-(*pc++));
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break;
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case SETTABLEDUP:
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*S->top = *(S->top-1);
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S->top++;
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luaV_settable(S->top-(3+1)-(*pc++));
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break;
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case SETLISTW: aux += highbyte(*pc++);
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case SETLIST: aux += *pc++; {
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int n = *(pc++);
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12
manual.tex
12
manual.tex
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@ -1,4 +1,4 @@
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% $Id: manual.tex,v 1.24 1999/02/25 19:13:56 roberto Exp roberto $
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% $Id: manual.tex,v 1.25 1999/03/04 21:23:39 roberto Exp roberto $
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\documentclass[11pt]{article}
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\usepackage{fullpage,bnf}
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@ -41,7 +41,7 @@ Waldemar Celes
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\tecgraf\ --- Computer Science Department --- PUC-Rio
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}
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%\date{\small \verb$Date: 1999/02/25 19:13:56 $}
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%\date{\small \verb$Date: 1999/03/04 21:23:39 $}
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\maketitle
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@ -697,14 +697,6 @@ according to its condition.
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Its final value is the value of the chosen expression.
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An absent else-part is equivalent to \verb|else nil|.
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\subsubsection{Assignment Expressions}
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\begin{Produc}
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\produc{exp}{\ter{(} varlist1 \ter{=} explist1 \ter{)}}
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\end{Produc}%
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An \Index{assignment expression} executes a multiple assignment,
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and results in the final value of its first right hand expression
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(that is, the value assigned to the first variable in the variable list).
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\subsubsection{Table Constructors} \label{tableconstructor}
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Table \Index{constructors} are expressions that create tables;
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every time a constructor is evaluated, a new table is created.
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