mirror of https://github.com/rusefi/lua.git
'break' does not need to be last statement in a block +
'explist1' -> 'explist' + moving a few functions around
This commit is contained in:
Roberto Ierusalimschy
parent
7b968bb514
commit
0009ac1f3a
167
lparser.c
167
lparser.c
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@ -1,5 +1,5 @@
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/*
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** $Id: lparser.c,v 2.103 2011/02/09 17:03:18 roberto Exp $
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** $Id: lparser.c,v 2.104 2011/02/10 14:50:41 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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@ -53,7 +53,7 @@ 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 statlist (LexState *ls);
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static void statement (LexState *ls);
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static void expr (LexState *ls, expdesc *v);
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@ -583,35 +583,40 @@ static void open_mainfunc (LexState *ls, FuncState *fs, BlockCnt *bl) {
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}
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Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
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Dyndata *dyd, const char *name) {
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LexState lexstate;
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FuncState funcstate;
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BlockCnt bl;
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TString *tname = luaS_new(L, name);
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setsvalue2s(L, L->top, tname); /* push name to protect it */
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incr_top(L);
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lexstate.buff = buff;
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lexstate.dyd = dyd;
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dyd->actvar.n = dyd->gt.n = dyd->label.n = 0;
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luaX_setinput(L, &lexstate, z, tname);
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open_mainfunc(&lexstate, &funcstate, &bl);
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luaX_next(&lexstate); /* read first token */
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statlist(&lexstate); /* main body */
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check(&lexstate, TK_EOS);
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close_func(&lexstate);
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L->top--; /* pop name */
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lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs);
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return funcstate.f;
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}
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/*============================================================*/
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/* GRAMMAR RULES */
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/*============================================================*/
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/*
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** check whether current token is in the follow set of a block.
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** 'until' closes syntactical blocks, but do not close scope,
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** so it handled in separate.
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*/
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static int block_follow (LexState *ls, int withuntil) {
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switch (ls->t.token) {
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case TK_ELSE: case TK_ELSEIF:
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case TK_END: case TK_EOS:
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return 1;
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case TK_UNTIL: return withuntil;
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default: return 0;
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}
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}
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static void statlist (LexState *ls) {
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/* statlist -> { stat [`;'] } */
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while (!block_follow(ls, 1)) {
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if (ls->t.token == TK_RETURN) {
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statement(ls);
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return; /* 'return' must be last statement */
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}
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statement(ls);
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}
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}
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static void fieldsel (LexState *ls, expdesc *v) {
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/* fieldsel -> ['.' | ':'] NAME */
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FuncState *fs = ls->fs;
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@ -805,8 +810,8 @@ static void body (LexState *ls, expdesc *e, int ismethod, int line) {
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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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static int explist (LexState *ls, expdesc *v) {
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/* explist -> 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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@ -823,12 +828,12 @@ static void funcargs (LexState *ls, expdesc *f, int line) {
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expdesc args;
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int base, nparams;
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switch (ls->t.token) {
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case '(': { /* funcargs -> `(' [ explist1 ] `)' */
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case '(': { /* funcargs -> `(' [ explist ] `)' */
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luaX_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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explist(ls, &args);
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luaK_setmultret(fs, &args);
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}
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check_match(ls, ')', '(', line);
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@ -1079,22 +1084,6 @@ static void expr (LexState *ls, expdesc *v) {
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*/
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/*
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** check whether current token is in the follow set of a block.
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** 'until' closes syntactical blocks, but do not close scope,
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** so it handled in separate.
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*/
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static int block_follow (LexState *ls, int withuntil) {
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switch (ls->t.token) {
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case TK_ELSE: case TK_ELSEIF:
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case TK_END: case TK_EOS:
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return 1;
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case TK_UNTIL: return withuntil;
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default: return 0;
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}
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}
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static void block (LexState *ls) {
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/* block -> statlist */
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FuncState *fs = ls->fs;
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@ -1159,10 +1148,10 @@ static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
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"variable names");
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assignment(ls, &nv, nvars+1);
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}
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else { /* assignment -> `=' explist1 */
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else { /* assignment -> `=' explist */
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int nexps;
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checknext(ls, '=');
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nexps = explist1(ls, &e);
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nexps = explist(ls, &e);
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if (nexps != nvars) {
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adjust_assign(ls, nvars, nexps, &e);
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if (nexps > nvars)
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@ -1313,7 +1302,7 @@ static void fornum (LexState *ls, TString *varname, int line) {
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static void forlist (LexState *ls, TString *indexname) {
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/* forlist -> NAME {,NAME} IN explist1 forbody */
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/* forlist -> NAME {,NAME} IN explist forbody */
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FuncState *fs = ls->fs;
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expdesc e;
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int nvars = 4; /* gen, state, control, plus at least one declared var */
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@ -1331,7 +1320,7 @@ static void forlist (LexState *ls, TString *indexname) {
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}
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checknext(ls, TK_IN);
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line = ls->linenumber;
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adjust_assign(ls, 3, explist1(ls, &e), &e);
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adjust_assign(ls, 3, explist(ls, &e), &e);
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luaK_checkstack(fs, 3); /* extra space to call generator */
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forbody(ls, base, line, nvars - 3, 0);
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}
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@ -1399,7 +1388,7 @@ static void localfunc (LexState *ls) {
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static void localstat (LexState *ls) {
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/* stat -> LOCAL NAME {`,' NAME} [`=' explist1] */
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/* stat -> LOCAL NAME {`,' NAME} [`=' explist] */
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int nvars = 0;
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int nexps;
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expdesc e;
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@ -1408,7 +1397,7 @@ static void localstat (LexState *ls) {
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nvars++;
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} while (testnext(ls, ','));
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if (testnext(ls, '='))
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nexps = explist1(ls, &e);
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nexps = explist(ls, &e);
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else {
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e.k = VVOID;
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nexps = 0;
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@ -1459,14 +1448,14 @@ static void exprstat (LexState *ls) {
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static void retstat (LexState *ls) {
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/* stat -> RETURN explist */
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/* stat -> RETURN [explist] [';'] */
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FuncState *fs = ls->fs;
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expdesc e;
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int first, nret; /* registers with returned values */
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if (block_follow(ls, 1) || ls->t.token == ';')
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first = nret = 0; /* return no values */
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else {
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nret = explist1(ls, &e); /* optional return values */
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nret = explist(ls, &e); /* optional return values */
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if (hasmultret(e.k)) {
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luaK_setmultret(fs, &e);
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if (e.k == VCALL && nret == 1) { /* tail call? */
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@ -1487,41 +1476,43 @@ static void retstat (LexState *ls) {
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}
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}
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luaK_ret(fs, first, nret);
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testnext(ls, ';'); /* skip optional semicollon */
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}
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static int statement (LexState *ls) {
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static void statement (LexState *ls) {
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int line = ls->linenumber; /* may be needed for error messages */
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enterlevel(ls);
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switch (ls->t.token) {
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case ';': { /* stat -> ';' (empty statement) */
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luaX_next(ls); /* skip ';' */
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return 0;
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break;
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}
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case TK_IF: { /* stat -> ifstat */
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ifstat(ls, line);
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return 0;
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break;
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}
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case TK_WHILE: { /* stat -> whilestat */
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whilestat(ls, line);
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return 0;
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break;
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}
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case TK_DO: { /* stat -> DO block END */
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luaX_next(ls); /* skip DO */
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block(ls);
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check_match(ls, TK_END, TK_DO, line);
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return 0;
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break;
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}
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case TK_FOR: { /* stat -> forstat */
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forstat(ls, line);
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return 0;
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break;
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}
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case TK_REPEAT: { /* stat -> repeatstat */
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repeatstat(ls, line);
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return 0;
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break;
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}
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case TK_FUNCTION: { /* stat -> funcstat */
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funcstat(ls, line);
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return 0;
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break;
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}
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case TK_LOCAL: { /* stat -> localstat */
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luaX_next(ls); /* skip LOCAL */
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@ -1529,50 +1520,62 @@ static int statement (LexState *ls) {
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localfunc(ls);
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else
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localstat(ls);
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return 0;
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break;
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}
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case '@': { /* stat -> label */
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luaX_next(ls); /* skip '@' */
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labelstat(ls, str_checkname(ls));
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return 0;
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break;
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}
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case TK_RETURN: { /* stat -> retstat */
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luaX_next(ls); /* skip RETURN */
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retstat(ls);
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return 1; /* must be last statement */
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break;
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}
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case TK_BREAK: { /* stat -> breakstat */
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luaX_next(ls); /* skip BREAK */
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/* code it as "goto 'break'" */
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gotostat(ls, luaS_new(ls->L, "break"), line);
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return 1; /* must be last statement */
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break;
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}
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case TK_GOTO: { /* stat -> 'goto' NAME */
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luaX_next(ls); /* skip GOTO */
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gotostat(ls, str_checkname(ls), line);
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return 0;
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break;
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}
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default: { /* stat -> func | assignment */
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exprstat(ls);
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return 0;
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break;
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}
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}
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}
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static void statlist (LexState *ls) {
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/* statlist -> { stat [`;'] } */
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int islast = 0;
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enterlevel(ls);
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while (!islast && !block_follow(ls, 1)) {
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islast = statement(ls);
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if (islast)
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testnext(ls, ';');
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lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
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ls->fs->freereg >= ls->fs->nactvar);
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ls->fs->freereg = ls->fs->nactvar; /* free registers */
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}
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lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
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ls->fs->freereg >= ls->fs->nactvar);
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ls->fs->freereg = ls->fs->nactvar; /* free registers */
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leavelevel(ls);
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}
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/* }====================================================================== */
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Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff,
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Dyndata *dyd, const char *name) {
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LexState lexstate;
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FuncState funcstate;
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BlockCnt bl;
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TString *tname = luaS_new(L, name);
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setsvalue2s(L, L->top, tname); /* push name to protect it */
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incr_top(L);
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lexstate.buff = buff;
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lexstate.dyd = dyd;
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dyd->actvar.n = dyd->gt.n = dyd->label.n = 0;
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luaX_setinput(L, &lexstate, z, tname);
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open_mainfunc(&lexstate, &funcstate, &bl);
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luaX_next(&lexstate); /* read first token */
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statlist(&lexstate); /* main body */
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check(&lexstate, TK_EOS);
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close_func(&lexstate);
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L->top--; /* pop name */
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lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs);
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return funcstate.f;
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}
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