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make more clear "primitive" recursive definitions
This commit is contained in:
Roberto Ierusalimschy
parent
04b143ddf9
commit
0050d983fc
206
lparser.c
206
lparser.c
@ -1,5 +1,5 @@
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/*
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** $Id: lparser.c,v 1.197 2002/11/22 13:59:04 roberto Exp roberto $
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** $Id: lparser.c,v 1.198 2002/11/22 16:35:20 roberto Exp roberto $
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** Lua Parser
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** See Copyright Notice in lua.h
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*/
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@ -47,9 +47,7 @@ typedef struct BlockCnt {
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/*
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** prototypes for recursive non-terminal functions
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*/
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static void body (LexState *ls, expdesc *v, int needself, int line);
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static void chunk (LexState *ls);
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static void constructor (LexState *ls, expdesc *v);
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static void expr (LexState *ls, expdesc *v);
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@ -400,69 +398,6 @@ static void luaY_index (LexState *ls, expdesc *v) {
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}
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static int explist1 (LexState *ls, expdesc *v) {
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/* explist1 -> expr { `,' expr } */
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int n = 1; /* at least one expression */
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expr(ls, v);
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while (testnext(ls, ',')) {
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luaK_exp2nextreg(ls->fs, v);
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expr(ls, v);
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n++;
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}
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return n;
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}
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static void funcargs (LexState *ls, expdesc *f) {
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FuncState *fs = ls->fs;
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expdesc args;
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int base, nparams;
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int line = ls->linenumber;
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switch (ls->t.token) {
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case '(': { /* funcargs -> `(' [ explist1 ] `)' */
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if (line != ls->lastline)
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luaX_syntaxerror(ls,"ambiguous syntax (function call x new statement)");
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next(ls);
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if (ls->t.token == ')') /* arg list is empty? */
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args.k = VVOID;
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else {
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explist1(ls, &args);
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luaK_setcallreturns(fs, &args, LUA_MULTRET);
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}
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check_match(ls, ')', '(', line);
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break;
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}
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case '{': { /* funcargs -> constructor */
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constructor(ls, &args);
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break;
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}
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case TK_STRING: { /* funcargs -> STRING */
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codestring(ls, &args, ls->t.seminfo.ts);
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next(ls); /* must use `seminfo' before `next' */
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break;
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}
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default: {
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luaX_syntaxerror(ls, "function arguments expected");
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return;
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}
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}
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lua_assert(f->k == VNONRELOC);
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base = f->info; /* base register for call */
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if (args.k == VCALL)
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nparams = LUA_MULTRET; /* open call */
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else {
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if (args.k != VVOID)
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luaK_exp2nextreg(fs, &args); /* close last argument */
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nparams = fs->freereg - (base+1);
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}
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init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
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luaK_fixline(fs, line);
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fs->freereg = base+1; /* call remove function and arguments and leaves
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(unless changed) one result */
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}
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/*
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** {======================================================================
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** Rules for Constructors
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@ -578,11 +513,107 @@ static void constructor (LexState *ls, expdesc *t) {
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SETARG_C(fs->f->code[pc], luaO_log2(cc.nh)+1); /* set initial table size */
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}
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/* }====================================================================== */
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static void parlist (LexState *ls) {
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/* parlist -> [ param { `,' param } ] */
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int nparams = 0;
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int dots = 0;
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if (ls->t.token != ')') { /* is `parlist' not empty? */
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do {
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switch (ls->t.token) {
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case TK_DOTS: dots = 1; next(ls); break;
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case TK_NAME: new_localvar(ls, str_checkname(ls), nparams++); break;
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default: luaX_syntaxerror(ls, "<name> or `...' expected");
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}
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} while (!dots && testnext(ls, ','));
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}
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code_params(ls, nparams, dots);
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}
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static void body (LexState *ls, expdesc *e, int needself, int line) {
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/* body -> `(' parlist `)' chunk END */
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FuncState new_fs;
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open_func(ls, &new_fs);
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new_fs.f->lineDefined = line;
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check(ls, '(');
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if (needself)
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create_local(ls, "self");
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parlist(ls);
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check(ls, ')');
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chunk(ls);
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check_match(ls, TK_END, TK_FUNCTION, line);
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close_func(ls);
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pushclosure(ls, &new_fs, e);
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}
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static int explist1 (LexState *ls, expdesc *v) {
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/* explist1 -> expr { `,' expr } */
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int n = 1; /* at least one expression */
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expr(ls, v);
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while (testnext(ls, ',')) {
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luaK_exp2nextreg(ls->fs, v);
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expr(ls, v);
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n++;
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}
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return n;
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}
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static void funcargs (LexState *ls, expdesc *f) {
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FuncState *fs = ls->fs;
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expdesc args;
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int base, nparams;
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int line = ls->linenumber;
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switch (ls->t.token) {
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case '(': { /* funcargs -> `(' [ explist1 ] `)' */
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if (line != ls->lastline)
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luaX_syntaxerror(ls,"ambiguous syntax (function call x new statement)");
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next(ls);
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if (ls->t.token == ')') /* arg list is empty? */
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args.k = VVOID;
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else {
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explist1(ls, &args);
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luaK_setcallreturns(fs, &args, LUA_MULTRET);
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}
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check_match(ls, ')', '(', line);
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break;
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}
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case '{': { /* funcargs -> constructor */
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constructor(ls, &args);
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break;
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}
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case TK_STRING: { /* funcargs -> STRING */
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codestring(ls, &args, ls->t.seminfo.ts);
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next(ls); /* must use `seminfo' before `next' */
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break;
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}
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default: {
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luaX_syntaxerror(ls, "function arguments expected");
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return;
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}
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}
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lua_assert(f->k == VNONRELOC);
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base = f->info; /* base register for call */
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if (args.k == VCALL)
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nparams = LUA_MULTRET; /* open call */
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else {
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if (args.k != VVOID)
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luaK_exp2nextreg(fs, &args); /* close last argument */
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nparams = fs->freereg - (base+1);
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}
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init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
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luaK_fixline(fs, line);
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fs->freereg = base+1; /* call remove function and arguments and leaves
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(unless changed) one result */
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}
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/*
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** {======================================================================
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@ -703,8 +734,6 @@ static void simpleexp (LexState *ls, expdesc *v) {
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}
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static UnOpr getunopr (int op) {
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switch (op) {
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case TK_NOT: return OPR_NOT;
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@ -788,6 +817,7 @@ static void expr (LexState *ls, expdesc *v) {
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/* }==================================================================== */
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/*
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** {======================================================================
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** Rules for Statements
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@ -1268,43 +1298,6 @@ static int statement (LexState *ls) {
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}
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static void parlist (LexState *ls) {
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/* parlist -> [ param { `,' param } ] */
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int nparams = 0;
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int dots = 0;
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if (ls->t.token != ')') { /* is `parlist' not empty? */
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do {
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switch (ls->t.token) {
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case TK_DOTS: dots = 1; next(ls); break;
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case TK_NAME: new_localvar(ls, str_checkname(ls), nparams++); break;
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default: luaX_syntaxerror(ls, "<name> or `...' expected");
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}
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} while (!dots && testnext(ls, ','));
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}
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code_params(ls, nparams, dots);
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}
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static void body (LexState *ls, expdesc *e, int needself, int line) {
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/* body -> `(' parlist `)' chunk END */
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FuncState new_fs;
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open_func(ls, &new_fs);
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new_fs.f->lineDefined = line;
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check(ls, '(');
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if (needself)
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create_local(ls, "self");
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parlist(ls);
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check(ls, ')');
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chunk(ls);
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check_match(ls, TK_END, TK_FUNCTION, line);
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close_func(ls);
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pushclosure(ls, &new_fs, e);
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}
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/* }====================================================================== */
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static void chunk (LexState *ls) {
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/* chunk -> { stat [`;'] } */
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int islast = 0;
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@ -1318,3 +1311,4 @@ static void chunk (LexState *ls) {
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leavelevel(ls);
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}
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/* }====================================================================== */
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