mirror of
https://github.com/lua/lua.git
synced 2024-11-24 02:33:48 +08:00
1310 lines
34 KiB
C
1310 lines
34 KiB
C
/*
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** $Id: lparser.c,v 1.190 2002/07/04 18:23:42 roberto Exp $
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** Lua Parser
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** See Copyright Notice in lua.h
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*/
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#include <string.h>
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#include "lua.h"
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#include "lcode.h"
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#include "ldebug.h"
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#include "lfunc.h"
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#include "llex.h"
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#include "lmem.h"
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#include "lobject.h"
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#include "lopcodes.h"
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#include "lparser.h"
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#include "lstate.h"
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#include "lstring.h"
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#define getlocvar(fs, i) ((fs)->f->locvars[(fs)->actvar[i]])
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/*
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** nodes for block list (list of active blocks)
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*/
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typedef struct BlockCnt {
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struct BlockCnt *previous; /* chain */
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int breaklist; /* list of jumps out of this loop */
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int nactvar; /* # active local variables outside the breakable structure */
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int upval; /* true if some variable in the block is an upvalue */
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int isbreakable; /* true if `block' is a loop */
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} 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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static void next (LexState *ls) {
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ls->lastline = ls->linenumber;
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if (ls->lookahead.token != TK_EOS) { /* is there a look-ahead token? */
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ls->t = ls->lookahead; /* use this one */
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ls->lookahead.token = TK_EOS; /* and discharge it */
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}
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else
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ls->t.token = luaX_lex(ls, &ls->t.seminfo); /* read next token */
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}
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static void lookahead (LexState *ls) {
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lua_assert(ls->lookahead.token == TK_EOS);
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ls->lookahead.token = luaX_lex(ls, &ls->lookahead.seminfo);
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}
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static void error_expected (LexState *ls, int token) {
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luaX_syntaxerror(ls,
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luaO_pushfstring(ls->L, "`%s' expected", luaX_token2str(ls, token)));
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}
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static int testnext (LexState *ls, int c) {
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if (ls->t.token == c) {
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next(ls);
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return 1;
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}
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else return 0;
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}
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static void check (LexState *ls, int c) {
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if (!testnext(ls, c))
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error_expected(ls, c);
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}
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#define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); }
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static void check_match (LexState *ls, int what, int who, int where) {
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if (!testnext(ls, what)) {
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if (where == ls->linenumber)
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error_expected(ls, what);
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else {
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luaX_syntaxerror(ls, luaO_pushfstring(ls->L,
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"`%s' expected (to close `%s' at line %d)",
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luaX_token2str(ls, what), luaX_token2str(ls, who), where));
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}
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}
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}
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static TString *str_checkname (LexState *ls) {
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TString *ts;
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check_condition(ls, (ls->t.token == TK_NAME), "<name> expected");
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ts = ls->t.seminfo.ts;
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next(ls);
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return ts;
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}
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static void init_exp (expdesc *e, expkind k, int i) {
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e->f = e->t = NO_JUMP;
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e->k = k;
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e->info = i;
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}
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static void codestring (LexState *ls, expdesc *e, TString *s) {
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init_exp(e, VK, luaK_stringK(ls->fs, s));
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}
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static void checkname(LexState *ls, expdesc *e) {
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codestring(ls, e, str_checkname(ls));
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}
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static int luaI_registerlocalvar (LexState *ls, TString *varname) {
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FuncState *fs = ls->fs;
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Proto *f = fs->f;
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luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars,
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LocVar, MAX_INT, "");
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f->locvars[fs->nlocvars].varname = varname;
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return fs->nlocvars++;
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}
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static void new_localvar (LexState *ls, TString *name, int n) {
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FuncState *fs = ls->fs;
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luaX_checklimit(ls, fs->nactvar+n+1, MAXVARS, "local variables");
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fs->actvar[fs->nactvar+n] = luaI_registerlocalvar(ls, name);
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}
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static void adjustlocalvars (LexState *ls, int nvars) {
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FuncState *fs = ls->fs;
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fs->nactvar += nvars;
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for (; nvars; nvars--) {
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getlocvar(fs, fs->nactvar - nvars).startpc = fs->pc;
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}
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}
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static void removevars (LexState *ls, int tolevel) {
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FuncState *fs = ls->fs;
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while (fs->nactvar > tolevel)
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getlocvar(fs, --fs->nactvar).endpc = fs->pc;
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}
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static void new_localvarstr (LexState *ls, const char *name, int n) {
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new_localvar(ls, luaS_new(ls->L, name), n);
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}
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static void create_local (LexState *ls, const char *name) {
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new_localvarstr(ls, name, 0);
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adjustlocalvars(ls, 1);
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}
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static int indexupvalue (FuncState *fs, expdesc *v) {
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int i;
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for (i=0; i<fs->f->nupvalues; i++) {
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if (fs->upvalues[i].k == v->k && fs->upvalues[i].info == v->info)
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return i;
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}
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/* new one */
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luaX_checklimit(fs->ls, fs->f->nupvalues+1, MAXUPVALUES, "upvalues");
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fs->upvalues[fs->f->nupvalues] = *v;
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return fs->f->nupvalues++;
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}
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static int searchvar (FuncState *fs, TString *n) {
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int i;
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for (i=fs->nactvar-1; i >= 0; i--) {
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if (n == getlocvar(fs, i).varname)
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return i;
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}
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return -1; /* not found */
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}
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static void markupval (FuncState *fs, int level) {
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BlockCnt *bl = fs->bl;
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while (bl && bl->nactvar > level) bl = bl->previous;
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if (bl) bl->upval = 1;
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}
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static void singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
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if (fs == NULL) /* no more levels? */
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init_exp(var, VGLOBAL, NO_REG); /* default is global variable */
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else {
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int v = searchvar(fs, n); /* look up at current level */
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if (v >= 0) {
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init_exp(var, VLOCAL, v);
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if (!base)
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markupval(fs, v); /* local will be used as an upval */
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}
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else { /* not found at current level; try upper one */
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singlevaraux(fs->prev, n, var, 0);
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if (var->k == VGLOBAL) {
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if (base)
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var->info = luaK_stringK(fs, n); /* info points to global name */
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}
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else { /* LOCAL or UPVAL */
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var->info = indexupvalue(fs, var);
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var->k = VUPVAL; /* upvalue in this level */
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}
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}
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}
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}
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static void singlevar (LexState *ls, expdesc *var, int base) {
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singlevaraux(ls->fs, str_checkname(ls), var, base);
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}
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static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
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FuncState *fs = ls->fs;
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int extra = nvars - nexps;
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if (e->k == VCALL) {
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extra++; /* includes call itself */
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if (extra <= 0) extra = 0;
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else luaK_reserveregs(fs, extra-1);
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luaK_setcallreturns(fs, e, extra); /* call provides the difference */
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}
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else {
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if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */
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if (extra > 0) {
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int reg = fs->freereg;
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luaK_reserveregs(fs, extra);
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luaK_nil(fs, reg, extra);
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}
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}
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}
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static void code_params (LexState *ls, int nparams, int dots) {
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FuncState *fs = ls->fs;
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adjustlocalvars(ls, nparams);
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luaX_checklimit(ls, fs->nactvar, MAXPARAMS, "parameters");
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fs->f->numparams = cast(lu_byte, fs->nactvar);
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fs->f->is_vararg = cast(lu_byte, dots);
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if (dots)
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create_local(ls, "arg");
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luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */
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}
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static void enterblock (FuncState *fs, BlockCnt *bl, int isbreakable) {
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bl->breaklist = NO_JUMP;
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bl->isbreakable = isbreakable;
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bl->nactvar = fs->nactvar;
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bl->upval = 0;
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bl->previous = fs->bl;
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fs->bl = bl;
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lua_assert(fs->freereg == fs->nactvar);
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}
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static void leaveblock (FuncState *fs) {
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BlockCnt *bl = fs->bl;
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fs->bl = bl->previous;
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removevars(fs->ls, bl->nactvar);
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if (bl->upval)
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luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0);
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lua_assert(bl->nactvar == fs->nactvar);
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fs->freereg = fs->nactvar; /* free registers */
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luaK_patchtohere(fs, bl->breaklist);
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}
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static void pushclosure (LexState *ls, FuncState *func, expdesc *v) {
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FuncState *fs = ls->fs;
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Proto *f = fs->f;
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int i;
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luaM_growvector(ls->L, f->p, fs->np, f->sizep, Proto *,
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MAXARG_Bx, "constant table overflow");
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f->p[fs->np++] = func->f;
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init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np-1));
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for (i=0; i<func->f->nupvalues; i++) {
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luaK_exp2nextreg(fs, &func->upvalues[i]);
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fs->freereg--; /* CLOSURE will use these values */
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}
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}
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static void open_func (LexState *ls, FuncState *fs) {
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Proto *f = luaF_newproto(ls->L);
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fs->f = f;
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fs->prev = ls->fs; /* linked list of funcstates */
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fs->ls = ls;
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fs->L = ls->L;
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ls->fs = fs;
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fs->pc = 0;
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fs->lasttarget = 0;
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fs->jpc = NO_JUMP;
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fs->freereg = 0;
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fs->nk = 0;
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fs->h = luaH_new(ls->L, 0, 0);
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fs->np = 0;
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fs->nlocvars = 0;
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fs->nactvar = 0;
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fs->bl = NULL;
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f->code = NULL;
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f->source = ls->source;
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f->maxstacksize = 1; /* register 0 is always valid */
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f->numparams = 0; /* default for main chunk */
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f->is_vararg = 0; /* default for main chunk */
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}
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static void close_func (LexState *ls) {
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lua_State *L = ls->L;
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FuncState *fs = ls->fs;
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Proto *f = fs->f;
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removevars(ls, 0);
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luaK_codeABC(fs, OP_RETURN, 0, 1, 0); /* final return */
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lua_assert(G(L)->roottable == fs->h);
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G(L)->roottable = fs->h->next;
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luaH_free(L, fs->h);
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luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
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luaM_reallocvector(L, f->lineinfo, f->sizecode, fs->pc, int);
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f->sizecode = fs->pc;
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luaM_reallocvector(L, f->k, f->sizek, fs->nk, TObject);
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f->sizek = fs->nk;
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luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
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f->sizep = fs->np;
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luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar);
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f->sizelocvars = fs->nlocvars;
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lua_assert(luaG_checkcode(f));
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lua_assert(fs->bl == NULL);
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ls->fs = fs->prev;
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}
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Proto *luaY_parser (lua_State *L, ZIO *z) {
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struct LexState lexstate;
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struct FuncState funcstate;
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luaX_setinput(L, &lexstate, z, luaS_new(L, zname(z)));
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open_func(&lexstate, &funcstate);
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next(&lexstate); /* read first token */
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chunk(&lexstate);
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check_condition(&lexstate, (lexstate.t.token == TK_EOS), "<eof> expected");
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close_func(&lexstate);
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lua_assert(funcstate.prev == NULL);
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lua_assert(funcstate.f->nupvalues == 0);
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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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static void luaY_field (LexState *ls, expdesc *v) {
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/* field -> ['.' | ':'] NAME */
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FuncState *fs = ls->fs;
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expdesc key;
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luaK_exp2anyreg(fs, v);
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next(ls); /* skip the dot or colon */
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checkname(ls, &key);
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luaK_indexed(fs, v, &key);
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}
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static void luaY_index (LexState *ls, expdesc *v) {
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/* index -> '[' expr ']' */
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next(ls); /* skip the '[' */
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expr(ls, v);
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luaK_exp2val(ls->fs, v);
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check(ls, ']');
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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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fs->f->lineinfo[f->info] = 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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** =======================================================================
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*/
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struct ConsControl {
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expdesc v; /* last list item read */
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expdesc *t; /* table descriptor */
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int nh; /* total number of `record' elements */
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int na; /* total number of array elements */
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int tostore; /* number of array elements pending to be stored */
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};
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static void recfield (LexState *ls, struct ConsControl *cc) {
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/* recfield -> (NAME | `['exp1`]') = exp1 */
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FuncState *fs = ls->fs;
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int reg = ls->fs->freereg;
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expdesc key, val;
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if (ls->t.token == TK_NAME) {
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luaX_checklimit(ls, cc->nh, MAX_INT, "items in a constructor");
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cc->nh++;
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checkname(ls, &key);
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}
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else /* ls->t.token == '[' */
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luaY_index(ls, &key);
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check(ls, '=');
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luaK_exp2RK(fs, &key);
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expr(ls, &val);
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luaK_exp2anyreg(fs, &val);
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luaK_codeABC(fs, OP_SETTABLE, val.info, cc->t->info, luaK_exp2RK(fs, &key));
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fs->freereg = reg; /* free registers */
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}
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static void closelistfield (FuncState *fs, struct ConsControl *cc) {
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if (cc->v.k == VVOID) return; /* there is no list item */
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luaK_exp2nextreg(fs, &cc->v);
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cc->v.k = VVOID;
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if (cc->tostore == LFIELDS_PER_FLUSH) {
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luaK_codeABx(fs, OP_SETLIST, cc->t->info, cc->na-1); /* flush */
|
|
cc->tostore = 0; /* no more items pending */
|
|
fs->freereg = cc->t->info + 1; /* free registers */
|
|
}
|
|
}
|
|
|
|
|
|
static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
|
|
if (cc->tostore == 0) return;
|
|
if (cc->v.k == VCALL) {
|
|
luaK_setcallreturns(fs, &cc->v, LUA_MULTRET);
|
|
luaK_codeABx(fs, OP_SETLISTO, cc->t->info, cc->na-1);
|
|
}
|
|
else {
|
|
if (cc->v.k != VVOID)
|
|
luaK_exp2nextreg(fs, &cc->v);
|
|
luaK_codeABx(fs, OP_SETLIST, cc->t->info, cc->na-1);
|
|
}
|
|
fs->freereg = cc->t->info + 1; /* free registers */
|
|
}
|
|
|
|
|
|
static void listfield (LexState *ls, struct ConsControl *cc) {
|
|
expr(ls, &cc->v);
|
|
luaX_checklimit(ls, cc->na, MAXARG_Bx, "items in a constructor");
|
|
cc->na++;
|
|
cc->tostore++;
|
|
}
|
|
|
|
|
|
static void constructor (LexState *ls, expdesc *t) {
|
|
/* constructor -> ?? */
|
|
FuncState *fs = ls->fs;
|
|
int line = ls->linenumber;
|
|
int pc = luaK_codeABC(fs, OP_NEWTABLE, 0, 0, 0);
|
|
struct ConsControl cc;
|
|
cc.na = cc.nh = cc.tostore = 0;
|
|
cc.t = t;
|
|
init_exp(t, VRELOCABLE, pc);
|
|
init_exp(&cc.v, VVOID, 0); /* no value (yet) */
|
|
luaK_exp2nextreg(ls->fs, t); /* fix it at stack top (for gc) */
|
|
check(ls, '{');
|
|
do {
|
|
lua_assert(cc.v.k == VVOID || cc.tostore > 0);
|
|
testnext(ls, ';'); /* compatibility only */
|
|
if (ls->t.token == '}') break;
|
|
closelistfield(fs, &cc);
|
|
switch(ls->t.token) {
|
|
case TK_NAME: { /* may be listfields or recfields */
|
|
lookahead(ls);
|
|
if (ls->lookahead.token != '=') /* expression? */
|
|
listfield(ls, &cc);
|
|
else
|
|
recfield(ls, &cc);
|
|
break;
|
|
}
|
|
case '[': { /* constructor_item -> recfield */
|
|
recfield(ls, &cc);
|
|
break;
|
|
}
|
|
default: { /* constructor_part -> listfield */
|
|
listfield(ls, &cc);
|
|
break;
|
|
}
|
|
}
|
|
} while (testnext(ls, ',') || testnext(ls, ';'));
|
|
check_match(ls, '}', '{', line);
|
|
lastlistfield(fs, &cc);
|
|
if (cc.na > 0)
|
|
SETARG_B(fs->f->code[pc], luaO_log2(cc.na-1)+2); /* set initial table size */
|
|
SETARG_C(fs->f->code[pc], luaO_log2(cc.nh)+1); /* set initial table size */
|
|
}
|
|
|
|
|
|
/* }====================================================================== */
|
|
|
|
|
|
|
|
|
|
/*
|
|
** {======================================================================
|
|
** Expression parsing
|
|
** =======================================================================
|
|
*/
|
|
|
|
|
|
static void prefixexp (LexState *ls, expdesc *v) {
|
|
/* prefixexp -> NAME | '(' expr ')' */
|
|
switch (ls->t.token) {
|
|
case '(': {
|
|
int line = ls->linenumber;
|
|
next(ls);
|
|
expr(ls, v);
|
|
check_match(ls, ')', '(', line);
|
|
luaK_dischargevars(ls->fs, v);
|
|
return;
|
|
}
|
|
case TK_NAME: {
|
|
singlevar(ls, v, 1);
|
|
return;
|
|
}
|
|
case '%': { /* for compatibility only */
|
|
next(ls); /* skip `%' */
|
|
singlevar(ls, v, 1);
|
|
check_condition(ls, v->k == VUPVAL, "global upvalues are obsolete");
|
|
return;
|
|
}
|
|
default: {
|
|
luaX_syntaxerror(ls, "unexpected symbol");
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
static void primaryexp (LexState *ls, expdesc *v) {
|
|
/* primaryexp ->
|
|
prefixexp { `.' NAME | `[' exp `]' | `:' NAME funcargs | funcargs } */
|
|
FuncState *fs = ls->fs;
|
|
prefixexp(ls, v);
|
|
for (;;) {
|
|
switch (ls->t.token) {
|
|
case '.': { /* field */
|
|
luaY_field(ls, v);
|
|
break;
|
|
}
|
|
case '[': { /* `[' exp1 `]' */
|
|
expdesc key;
|
|
luaK_exp2anyreg(fs, v);
|
|
luaY_index(ls, &key);
|
|
luaK_indexed(fs, v, &key);
|
|
break;
|
|
}
|
|
case ':': { /* `:' NAME funcargs */
|
|
expdesc key;
|
|
next(ls);
|
|
checkname(ls, &key);
|
|
luaK_self(fs, v, &key);
|
|
funcargs(ls, v);
|
|
break;
|
|
}
|
|
case '(': case TK_STRING: case '{': { /* funcargs */
|
|
luaK_exp2nextreg(fs, v);
|
|
funcargs(ls, v);
|
|
break;
|
|
}
|
|
default: return;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
static void simpleexp (LexState *ls, expdesc *v) {
|
|
/* simpleexp -> NUMBER | STRING | NIL | constructor | FUNCTION body
|
|
| primaryexp */
|
|
switch (ls->t.token) {
|
|
case TK_NUMBER: {
|
|
init_exp(v, VK, luaK_numberK(ls->fs, ls->t.seminfo.r));
|
|
next(ls); /* must use `seminfo' before `next' */
|
|
break;
|
|
}
|
|
case TK_STRING: {
|
|
codestring(ls, v, ls->t.seminfo.ts);
|
|
next(ls); /* must use `seminfo' before `next' */
|
|
break;
|
|
}
|
|
case TK_NIL: {
|
|
init_exp(v, VNIL, 0);
|
|
next(ls);
|
|
break;
|
|
}
|
|
case TK_TRUE: {
|
|
init_exp(v, VTRUE, 0);
|
|
next(ls);
|
|
break;
|
|
}
|
|
case TK_FALSE: {
|
|
init_exp(v, VFALSE, 0);
|
|
next(ls);
|
|
break;
|
|
}
|
|
case '{': { /* constructor */
|
|
constructor(ls, v);
|
|
break;
|
|
}
|
|
case TK_FUNCTION: {
|
|
next(ls);
|
|
body(ls, v, 0, ls->linenumber);
|
|
break;
|
|
}
|
|
default: {
|
|
primaryexp(ls, v);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
|
|
|
|
static UnOpr getunopr (int op) {
|
|
switch (op) {
|
|
case TK_NOT: return OPR_NOT;
|
|
case '-': return OPR_MINUS;
|
|
default: return OPR_NOUNOPR;
|
|
}
|
|
}
|
|
|
|
|
|
static BinOpr getbinopr (int op) {
|
|
switch (op) {
|
|
case '+': return OPR_ADD;
|
|
case '-': return OPR_SUB;
|
|
case '*': return OPR_MULT;
|
|
case '/': return OPR_DIV;
|
|
case '^': return OPR_POW;
|
|
case TK_CONCAT: return OPR_CONCAT;
|
|
case TK_NE: return OPR_NE;
|
|
case TK_EQ: return OPR_EQ;
|
|
case '<': return OPR_LT;
|
|
case TK_LE: return OPR_LE;
|
|
case '>': return OPR_GT;
|
|
case TK_GE: return OPR_GE;
|
|
case TK_AND: return OPR_AND;
|
|
case TK_OR: return OPR_OR;
|
|
default: return OPR_NOBINOPR;
|
|
}
|
|
}
|
|
|
|
|
|
static const struct {
|
|
lu_byte left; /* left priority for each binary operator */
|
|
lu_byte right; /* right priority */
|
|
} priority[] = { /* ORDER OPR */
|
|
{6, 6}, {6, 6}, {7, 7}, {7, 7}, /* arithmetic */
|
|
{10, 9}, {5, 4}, /* power and concat (right associative) */
|
|
{3, 3}, {3, 3}, /* equality */
|
|
{3, 3}, {3, 3}, {3, 3}, {3, 3}, /* order */
|
|
{2, 2}, {1, 1} /* logical (and/or) */
|
|
};
|
|
|
|
#define UNARY_PRIORITY 8 /* priority for unary operators */
|
|
|
|
|
|
/*
|
|
** subexpr -> (simplexep | unop subexpr) { binop subexpr }
|
|
** where `binop' is any binary operator with a priority higher than `limit'
|
|
*/
|
|
static BinOpr subexpr (LexState *ls, expdesc *v, int limit) {
|
|
BinOpr op;
|
|
UnOpr uop = getunopr(ls->t.token);
|
|
if (uop != OPR_NOUNOPR) {
|
|
next(ls);
|
|
subexpr(ls, v, UNARY_PRIORITY);
|
|
luaK_prefix(ls->fs, uop, v);
|
|
}
|
|
else simpleexp(ls, v);
|
|
/* expand while operators have priorities higher than `limit' */
|
|
op = getbinopr(ls->t.token);
|
|
while (op != OPR_NOBINOPR && cast(int, priority[op].left) > limit) {
|
|
expdesc v2;
|
|
BinOpr nextop;
|
|
next(ls);
|
|
luaK_infix(ls->fs, op, v);
|
|
/* read sub-expression with higher priority */
|
|
nextop = subexpr(ls, &v2, cast(int, priority[op].right));
|
|
luaK_posfix(ls->fs, op, v, &v2);
|
|
op = nextop;
|
|
}
|
|
return op; /* return first untreated operator */
|
|
}
|
|
|
|
|
|
static void expr (LexState *ls, expdesc *v) {
|
|
subexpr(ls, v, -1);
|
|
}
|
|
|
|
/* }==================================================================== */
|
|
|
|
|
|
/*
|
|
** {======================================================================
|
|
** Rules for Statements
|
|
** =======================================================================
|
|
*/
|
|
|
|
|
|
static int block_follow (int token) {
|
|
switch (token) {
|
|
case TK_ELSE: case TK_ELSEIF: case TK_END:
|
|
case TK_UNTIL: case TK_EOS:
|
|
return 1;
|
|
default: return 0;
|
|
}
|
|
}
|
|
|
|
|
|
static void block (LexState *ls) {
|
|
/* block -> chunk */
|
|
FuncState *fs = ls->fs;
|
|
BlockCnt bl;
|
|
enterblock(fs, &bl, 0);
|
|
chunk(ls);
|
|
lua_assert(bl.breaklist == NO_JUMP);
|
|
leaveblock(fs);
|
|
}
|
|
|
|
|
|
/*
|
|
** structure to chain all variables in the left-hand side of an
|
|
** assignment
|
|
*/
|
|
struct LHS_assign {
|
|
struct LHS_assign *prev;
|
|
expdesc v; /* variable (global, local, upvalue, or indexed) */
|
|
};
|
|
|
|
|
|
/*
|
|
** check whether, in an assignment to a local variable, the local variable
|
|
** is needed in a previous assignment (to a table). If so, save original
|
|
** local value in a safe place and use this safe copy in the previous
|
|
** assignment.
|
|
*/
|
|
static void check_conflict (LexState *ls, struct LHS_assign *lh, expdesc *v) {
|
|
FuncState *fs = ls->fs;
|
|
int extra = fs->freereg; /* eventual position to save local variable */
|
|
int conflict = 0;
|
|
for (; lh; lh = lh->prev) {
|
|
if (lh->v.k == VINDEXED) {
|
|
if (lh->v.info == v->info) { /* conflict? */
|
|
conflict = 1;
|
|
lh->v.info = extra; /* previous assignment will use safe copy */
|
|
}
|
|
if (lh->v.aux == v->info) { /* conflict? */
|
|
conflict = 1;
|
|
lh->v.aux = extra; /* previous assignment will use safe copy */
|
|
}
|
|
}
|
|
}
|
|
if (conflict) {
|
|
luaK_codeABC(fs, OP_MOVE, fs->freereg, v->info, 0); /* make copy */
|
|
luaK_reserveregs(fs, 1);
|
|
}
|
|
}
|
|
|
|
|
|
static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
|
|
expdesc e;
|
|
check_condition(ls, VLOCAL <= lh->v.k && lh->v.k <= VINDEXED,
|
|
"syntax error");
|
|
if (testnext(ls, ',')) { /* assignment -> `,' primaryexp assignment */
|
|
struct LHS_assign nv;
|
|
nv.prev = lh;
|
|
primaryexp(ls, &nv.v);
|
|
if (nv.v.k == VLOCAL)
|
|
check_conflict(ls, lh, &nv.v);
|
|
assignment(ls, &nv, nvars+1);
|
|
}
|
|
else { /* assignment -> `=' explist1 */
|
|
int nexps;
|
|
check(ls, '=');
|
|
nexps = explist1(ls, &e);
|
|
if (nexps != nvars) {
|
|
adjust_assign(ls, nvars, nexps, &e);
|
|
if (nexps > nvars)
|
|
ls->fs->freereg -= nexps - nvars; /* remove extra values */
|
|
}
|
|
else {
|
|
luaK_setcallreturns(ls->fs, &e, 1); /* close last expression */
|
|
luaK_storevar(ls->fs, &lh->v, &e);
|
|
return; /* avoid default */
|
|
}
|
|
}
|
|
init_exp(&e, VNONRELOC, ls->fs->freereg-1); /* default assignment */
|
|
luaK_storevar(ls->fs, &lh->v, &e);
|
|
}
|
|
|
|
|
|
static void cond (LexState *ls, expdesc *v) {
|
|
/* cond -> exp */
|
|
expr(ls, v); /* read condition */
|
|
if (v->k == VNIL) v->k = VFALSE; /* `falses' are all equal here */
|
|
luaK_goiftrue(ls->fs, v);
|
|
luaK_patchtohere(ls->fs, v->t);
|
|
}
|
|
|
|
|
|
/*
|
|
** The while statement optimizes its code by coding the condition
|
|
** after its body (and thus avoiding one jump in the loop).
|
|
*/
|
|
|
|
/*
|
|
** maximum size of expressions for optimizing `while' code
|
|
*/
|
|
#ifndef MAXEXPWHILE
|
|
#define MAXEXPWHILE 100
|
|
#endif
|
|
|
|
/*
|
|
** the call `luaK_goiffalse' may grow the size of an expression by
|
|
** at most this:
|
|
*/
|
|
#define EXTRAEXP 5
|
|
|
|
static void whilestat (LexState *ls, int line) {
|
|
/* whilestat -> WHILE cond DO block END */
|
|
Instruction codeexp[MAXEXPWHILE + EXTRAEXP];
|
|
int lineexp = 0;
|
|
int i;
|
|
int sizeexp;
|
|
FuncState *fs = ls->fs;
|
|
int whileinit, blockinit, expinit;
|
|
expdesc v;
|
|
BlockCnt bl;
|
|
next(ls); /* skip WHILE */
|
|
whileinit = luaK_jump(fs); /* jump to condition (which will be moved) */
|
|
expinit = luaK_getlabel(fs);
|
|
expr(ls, &v); /* parse condition */
|
|
if (v.k == VK) v.k = VTRUE; /* `trues' are all equal here */
|
|
lineexp = ls->linenumber;
|
|
luaK_goiffalse(fs, &v);
|
|
luaK_concat(fs, &v.f, fs->jpc);
|
|
fs->jpc = NO_JUMP;
|
|
sizeexp = fs->pc - expinit; /* size of expression code */
|
|
if (sizeexp > MAXEXPWHILE)
|
|
luaX_syntaxerror(ls, "`while' condition too complex");
|
|
for (i = 0; i < sizeexp; i++) /* save `exp' code */
|
|
codeexp[i] = fs->f->code[expinit + i];
|
|
fs->pc = expinit; /* remove `exp' code */
|
|
enterblock(fs, &bl, 1);
|
|
check(ls, TK_DO);
|
|
blockinit = luaK_getlabel(fs);
|
|
block(ls);
|
|
luaK_patchtohere(fs, whileinit); /* initial jump jumps to here */
|
|
/* move `exp' back to code */
|
|
if (v.t != NO_JUMP) v.t += fs->pc - expinit;
|
|
if (v.f != NO_JUMP) v.f += fs->pc - expinit;
|
|
for (i=0; i<sizeexp; i++)
|
|
luaK_code(fs, codeexp[i], lineexp);
|
|
check_match(ls, TK_END, TK_WHILE, line);
|
|
leaveblock(fs);
|
|
luaK_patchlist(fs, v.t, blockinit); /* true conditions go back to loop */
|
|
luaK_patchtohere(fs, v.f); /* false conditions finish the loop */
|
|
}
|
|
|
|
|
|
static void repeatstat (LexState *ls, int line) {
|
|
/* repeatstat -> REPEAT block UNTIL cond */
|
|
FuncState *fs = ls->fs;
|
|
int repeat_init = luaK_getlabel(fs);
|
|
expdesc v;
|
|
BlockCnt bl;
|
|
enterblock(fs, &bl, 1);
|
|
next(ls);
|
|
block(ls);
|
|
check_match(ls, TK_UNTIL, TK_REPEAT, line);
|
|
cond(ls, &v);
|
|
luaK_patchlist(fs, v.f, repeat_init);
|
|
leaveblock(fs);
|
|
}
|
|
|
|
|
|
static int exp1 (LexState *ls) {
|
|
expdesc e;
|
|
int k;
|
|
expr(ls, &e);
|
|
k = e.k;
|
|
luaK_exp2nextreg(ls->fs, &e);
|
|
return k;
|
|
}
|
|
|
|
|
|
static void fornum (LexState *ls, TString *varname, int line) {
|
|
/* fornum -> NAME = exp1,exp1[,exp1] DO body */
|
|
FuncState *fs = ls->fs;
|
|
int prep, endfor;
|
|
int base = fs->freereg;
|
|
new_localvar(ls, varname, 0);
|
|
new_localvarstr(ls, "(for limit)", 1);
|
|
new_localvarstr(ls, "(for step)", 2);
|
|
check(ls, '=');
|
|
exp1(ls); /* initial value */
|
|
check(ls, ',');
|
|
exp1(ls); /* limit */
|
|
if (testnext(ls, ','))
|
|
exp1(ls); /* optional step */
|
|
else { /* default step = 1 */
|
|
luaK_codeABx(fs, OP_LOADK, fs->freereg, luaK_numberK(fs, 1));
|
|
luaK_reserveregs(fs, 1);
|
|
}
|
|
adjustlocalvars(ls, 3); /* scope for control variables */
|
|
luaK_codeABC(fs, OP_SUB, fs->freereg - 3, fs->freereg - 3, fs->freereg - 1);
|
|
luaK_jump(fs);
|
|
prep = luaK_getlabel(fs);
|
|
check(ls, TK_DO);
|
|
block(ls);
|
|
luaK_patchtohere(fs, prep-1);
|
|
endfor = luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP);
|
|
luaK_fixline(fs, line); /* pretend that `OP_FOR' starts the loop */
|
|
luaK_patchlist(fs, endfor, prep);
|
|
}
|
|
|
|
|
|
static void forlist (LexState *ls, TString *indexname) {
|
|
/* forlist -> NAME {,NAME} IN explist1 DO body */
|
|
FuncState *fs = ls->fs;
|
|
expdesc e;
|
|
int line;
|
|
int nvars = 0;
|
|
int prep;
|
|
int base = fs->freereg;
|
|
new_localvarstr(ls, "(for generator)", nvars++);
|
|
new_localvarstr(ls, "(for state)", nvars++);
|
|
new_localvar(ls, indexname, nvars++);
|
|
while (testnext(ls, ','))
|
|
new_localvar(ls, str_checkname(ls), nvars++);
|
|
check(ls, TK_IN);
|
|
line = ls->linenumber;
|
|
adjust_assign(ls, 3, explist1(ls, &e), &e);
|
|
luaK_reserveregs(fs, nvars - 3); /* registers for other variables */
|
|
luaK_codeAsBx(fs, OP_TFORPREP, base, NO_JUMP);
|
|
adjustlocalvars(ls, nvars); /* scope for all variables */
|
|
check(ls, TK_DO);
|
|
prep = luaK_getlabel(fs);
|
|
block(ls);
|
|
luaK_patchtohere(fs, prep-1);
|
|
removevars(fs->ls, fs->nactvar - nvars); /* deactivate locals for next op. */
|
|
luaK_codeABC(fs, OP_TFORLOOP, base, 0, nvars - 3);
|
|
luaK_fixline(fs, line); /* pretend that `OP_FOR' starts the loop */
|
|
luaK_patchlist(fs, luaK_jump(fs), prep);
|
|
}
|
|
|
|
|
|
static void forstat (LexState *ls, int line) {
|
|
/* forstat -> fornum | forlist */
|
|
FuncState *fs = ls->fs;
|
|
TString *varname;
|
|
BlockCnt bl;
|
|
enterblock(fs, &bl, 1);
|
|
next(ls); /* skip `for' */
|
|
varname = str_checkname(ls); /* first variable name */
|
|
switch (ls->t.token) {
|
|
case '=': fornum(ls, varname, line); break;
|
|
case ',': case TK_IN: forlist(ls, varname); break;
|
|
default: luaX_syntaxerror(ls, "`=' or `in' expected");
|
|
}
|
|
check_match(ls, TK_END, TK_FOR, line);
|
|
leaveblock(fs);
|
|
}
|
|
|
|
|
|
static void test_then_block (LexState *ls, expdesc *v) {
|
|
/* test_then_block -> [IF | ELSEIF] cond THEN block */
|
|
next(ls); /* skip IF or ELSEIF */
|
|
cond(ls, v);
|
|
check(ls, TK_THEN);
|
|
block(ls); /* `then' part */
|
|
}
|
|
|
|
|
|
static void ifstat (LexState *ls, int line) {
|
|
/* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
|
|
FuncState *fs = ls->fs;
|
|
expdesc v;
|
|
int escapelist = NO_JUMP;
|
|
test_then_block(ls, &v); /* IF cond THEN block */
|
|
while (ls->t.token == TK_ELSEIF) {
|
|
luaK_concat(fs, &escapelist, luaK_jump(fs));
|
|
luaK_patchtohere(fs, v.f);
|
|
test_then_block(ls, &v); /* ELSEIF cond THEN block */
|
|
}
|
|
if (ls->t.token == TK_ELSE) {
|
|
luaK_concat(fs, &escapelist, luaK_jump(fs));
|
|
luaK_patchtohere(fs, v.f);
|
|
next(ls); /* skip ELSE (after patch, for correct line info) */
|
|
block(ls); /* `else' part */
|
|
}
|
|
else
|
|
luaK_concat(fs, &escapelist, v.f);
|
|
luaK_patchtohere(fs, escapelist);
|
|
check_match(ls, TK_END, TK_IF, line);
|
|
}
|
|
|
|
|
|
static void localfunc (LexState *ls) {
|
|
expdesc v, b;
|
|
new_localvar(ls, str_checkname(ls), 0);
|
|
init_exp(&v, VLOCAL, ls->fs->freereg++);
|
|
adjustlocalvars(ls, 1);
|
|
body(ls, &b, 0, ls->linenumber);
|
|
luaK_storevar(ls->fs, &v, &b);
|
|
}
|
|
|
|
|
|
static void localstat (LexState *ls) {
|
|
/* stat -> LOCAL NAME {`,' NAME} [`=' explist1] */
|
|
int nvars = 0;
|
|
int nexps;
|
|
expdesc e;
|
|
do {
|
|
new_localvar(ls, str_checkname(ls), nvars++);
|
|
} while (testnext(ls, ','));
|
|
if (testnext(ls, '='))
|
|
nexps = explist1(ls, &e);
|
|
else {
|
|
e.k = VVOID;
|
|
nexps = 0;
|
|
}
|
|
adjust_assign(ls, nvars, nexps, &e);
|
|
adjustlocalvars(ls, nvars);
|
|
}
|
|
|
|
|
|
static int funcname (LexState *ls, expdesc *v) {
|
|
/* funcname -> NAME {field} [`:' NAME] */
|
|
int needself = 0;
|
|
singlevar(ls, v, 1);
|
|
while (ls->t.token == '.')
|
|
luaY_field(ls, v);
|
|
if (ls->t.token == ':') {
|
|
needself = 1;
|
|
luaY_field(ls, v);
|
|
}
|
|
return needself;
|
|
}
|
|
|
|
|
|
static void funcstat (LexState *ls, int line) {
|
|
/* funcstat -> FUNCTION funcname body */
|
|
int needself;
|
|
expdesc v, b;
|
|
next(ls); /* skip FUNCTION */
|
|
needself = funcname(ls, &v);
|
|
body(ls, &b, needself, line);
|
|
luaK_storevar(ls->fs, &v, &b);
|
|
}
|
|
|
|
|
|
static void exprstat (LexState *ls) {
|
|
/* stat -> func | assignment */
|
|
FuncState *fs = ls->fs;
|
|
struct LHS_assign v;
|
|
primaryexp(ls, &v.v);
|
|
if (v.v.k == VCALL) { /* stat -> func */
|
|
luaK_setcallreturns(fs, &v.v, 0); /* call statement uses no results */
|
|
}
|
|
else { /* stat -> assignment */
|
|
v.prev = NULL;
|
|
assignment(ls, &v, 1);
|
|
}
|
|
}
|
|
|
|
|
|
static void retstat (LexState *ls) {
|
|
/* stat -> RETURN explist */
|
|
FuncState *fs = ls->fs;
|
|
expdesc e;
|
|
int first, nret; /* registers with returned values */
|
|
next(ls); /* skip RETURN */
|
|
if (block_follow(ls->t.token) || ls->t.token == ';')
|
|
first = nret = 0; /* return no values */
|
|
else {
|
|
nret = explist1(ls, &e); /* optional return values */
|
|
if (e.k == VCALL) {
|
|
luaK_setcallreturns(fs, &e, LUA_MULTRET);
|
|
if (nret == 1) { /* tail call? */
|
|
SET_OPCODE(getcode(fs,&e), OP_TAILCALL);
|
|
lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar);
|
|
}
|
|
first = fs->nactvar;
|
|
nret = LUA_MULTRET; /* return all values */
|
|
}
|
|
else {
|
|
if (nret == 1) /* only one single value? */
|
|
first = luaK_exp2anyreg(fs, &e);
|
|
else {
|
|
luaK_exp2nextreg(fs, &e); /* values must go to the `stack' */
|
|
first = fs->nactvar; /* return all `active' values */
|
|
lua_assert(nret == fs->freereg - first);
|
|
}
|
|
}
|
|
}
|
|
luaK_codeABC(fs, OP_RETURN, first, nret+1, 0);
|
|
}
|
|
|
|
|
|
static void breakstat (LexState *ls) {
|
|
/* stat -> BREAK [NAME] */
|
|
FuncState *fs = ls->fs;
|
|
BlockCnt *bl = fs->bl;
|
|
int upval = 0;
|
|
next(ls); /* skip BREAK */
|
|
while (bl && !bl->isbreakable) {
|
|
upval |= bl->upval;
|
|
bl = bl->previous;
|
|
}
|
|
if (!bl)
|
|
luaX_syntaxerror(ls, "no loop to break");
|
|
if (upval)
|
|
luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0);
|
|
luaK_concat(fs, &bl->breaklist, luaK_jump(fs));
|
|
}
|
|
|
|
|
|
static int statement (LexState *ls) {
|
|
int line = ls->linenumber; /* may be needed for error messages */
|
|
switch (ls->t.token) {
|
|
case TK_IF: { /* stat -> ifstat */
|
|
ifstat(ls, line);
|
|
return 0;
|
|
}
|
|
case TK_WHILE: { /* stat -> whilestat */
|
|
whilestat(ls, line);
|
|
return 0;
|
|
}
|
|
case TK_DO: { /* stat -> DO block END */
|
|
next(ls); /* skip DO */
|
|
block(ls);
|
|
check_match(ls, TK_END, TK_DO, line);
|
|
return 0;
|
|
}
|
|
case TK_FOR: { /* stat -> forstat */
|
|
forstat(ls, line);
|
|
return 0;
|
|
}
|
|
case TK_REPEAT: { /* stat -> repeatstat */
|
|
repeatstat(ls, line);
|
|
return 0;
|
|
}
|
|
case TK_FUNCTION: {
|
|
funcstat(ls, line); /* stat -> funcstat */
|
|
return 0;
|
|
}
|
|
case TK_LOCAL: { /* stat -> localstat */
|
|
next(ls); /* skip LOCAL */
|
|
if (testnext(ls, TK_FUNCTION)) /* local function? */
|
|
localfunc(ls);
|
|
else
|
|
localstat(ls);
|
|
return 0;
|
|
}
|
|
case TK_RETURN: { /* stat -> retstat */
|
|
retstat(ls);
|
|
return 1; /* must be last statement */
|
|
}
|
|
case TK_BREAK: { /* stat -> breakstat */
|
|
breakstat(ls);
|
|
return 1; /* must be last statement */
|
|
}
|
|
default: {
|
|
exprstat(ls);
|
|
return 0; /* to avoid warnings */
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
static void parlist (LexState *ls) {
|
|
/* parlist -> [ param { `,' param } ] */
|
|
int nparams = 0;
|
|
int dots = 0;
|
|
if (ls->t.token != ')') { /* is `parlist' not empty? */
|
|
do {
|
|
switch (ls->t.token) {
|
|
case TK_DOTS: dots = 1; next(ls); break;
|
|
case TK_NAME: new_localvar(ls, str_checkname(ls), nparams++); break;
|
|
default: luaX_syntaxerror(ls, "<name> or `...' expected");
|
|
}
|
|
} while (!dots && testnext(ls, ','));
|
|
}
|
|
code_params(ls, nparams, dots);
|
|
}
|
|
|
|
|
|
static void body (LexState *ls, expdesc *e, int needself, int line) {
|
|
/* body -> `(' parlist `)' chunk END */
|
|
FuncState new_fs;
|
|
open_func(ls, &new_fs);
|
|
new_fs.f->lineDefined = line;
|
|
check(ls, '(');
|
|
if (needself)
|
|
create_local(ls, "self");
|
|
parlist(ls);
|
|
check(ls, ')');
|
|
chunk(ls);
|
|
check_match(ls, TK_END, TK_FUNCTION, line);
|
|
close_func(ls);
|
|
pushclosure(ls, &new_fs, e);
|
|
}
|
|
|
|
|
|
/* }====================================================================== */
|
|
|
|
|
|
static void chunk (LexState *ls) {
|
|
/* chunk -> { stat [`;'] } */
|
|
int islast = 0;
|
|
while (!islast && !block_follow(ls->t.token)) {
|
|
islast = statement(ls);
|
|
testnext(ls, ';');
|
|
lua_assert(ls->fs->freereg >= ls->fs->nactvar);
|
|
ls->fs->freereg = ls->fs->nactvar; /* free registers */
|
|
}
|
|
}
|
|
|