lparser.c
上传用户:yisoukefu
上传日期:2020-08-09
资源大小:39506k
文件大小:36k
- /*
- ** $Id: lparser.c,v 2.40 2005/12/22 16:19:56 roberto Exp $
- ** Lua Parser
- ** See Copyright Notice in lua.h
- */
- #include <string.h>
- #define lparser_c
- #define LUA_CORE
- #include "lua.h"
- #include "lcode.h"
- #include "ldebug.h"
- #include "ldo.h"
- #include "lfunc.h"
- #include "llex.h"
- #include "lmem.h"
- #include "lobject.h"
- #include "lopcodes.h"
- #include "lparser.h"
- #include "lstate.h"
- #include "lstring.h"
- #define hasmultret(k) ((k) == VCALL || (k) == VVARARG)
- #define getlocvar(fs, i) ((fs)->f->locvars[(fs)->actvar[i]])
- #define luaY_checklimit(fs,v,l,m) if ((v)>(l)) errorlimit(fs,l,m)
- /*
- ** nodes for block list (list of active blocks)
- */
- typedef struct BlockCnt {
- struct BlockCnt *previous; /* chain */
- int breaklist; /* list of jumps out of this loop */
- lu_byte nactvar; /* # active locals outside the breakable structure */
- lu_byte upval; /* true if some variable in the block is an upvalue */
- lu_byte isbreakable; /* true if `block' is a loop */
- } BlockCnt;
- /*
- ** prototypes for recursive non-terminal functions
- */
- static void chunk (LexState *ls);
- static void expr (LexState *ls, expdesc *v);
- static void anchor_token (LexState *ls) {
- if (ls->t.token == TK_NAME || ls->t.token == TK_STRING) {
- TString *ts = ls->t.seminfo.ts;
- luaX_newstring(ls, getstr(ts), ts->tsv.len);
- }
- }
- static void error_expected (LexState *ls, int token) {
- luaX_syntaxerror(ls,
- luaO_pushfstring(ls->L, LUA_QS " expected", luaX_token2str(ls, token)));
- }
- static void errorlimit (FuncState *fs, int limit, const char *what) {
- const char *msg = (fs->f->linedefined == 0) ?
- luaO_pushfstring(fs->L, "main function has more than %d %s", limit, what) :
- luaO_pushfstring(fs->L, "function at line %d has more than %d %s",
- fs->f->linedefined, limit, what);
- luaX_lexerror(fs->ls, msg, 0);
- }
- static int testnext (LexState *ls, int c) {
- if (ls->t.token == c) {
- luaX_next(ls);
- return 1;
- }
- else return 0;
- }
- static void check (LexState *ls, int c) {
- if (ls->t.token != c)
- error_expected(ls, c);
- }
- static void checknext (LexState *ls, int c) {
- check(ls, c);
- luaX_next(ls);
- }
- #define check_condition(ls,c,msg) { if (!(c)) luaX_syntaxerror(ls, msg); }
- static void check_match (LexState *ls, int what, int who, int where) {
- if (!testnext(ls, what)) {
- if (where == ls->linenumber)
- error_expected(ls, what);
- else {
- luaX_syntaxerror(ls, luaO_pushfstring(ls->L,
- LUA_QS " expected (to close " LUA_QS " at line %d)",
- luaX_token2str(ls, what), luaX_token2str(ls, who), where));
- }
- }
- }
- static TString *str_checkname (LexState *ls) {
- TString *ts;
- check(ls, TK_NAME);
- ts = ls->t.seminfo.ts;
- luaX_next(ls);
- return ts;
- }
- static void init_exp (expdesc *e, expkind k, int i) {
- e->f = e->t = NO_JUMP;
- e->k = k;
- e->u.s.info = i;
- }
- static void codestring (LexState *ls, expdesc *e, TString *s) {
- init_exp(e, VK, luaK_stringK(ls->fs, s));
- }
- static void checkname(LexState *ls, expdesc *e) {
- codestring(ls, e, str_checkname(ls));
- }
- static int registerlocalvar (LexState *ls, TString *varname) {
- FuncState *fs = ls->fs;
- Proto *f = fs->f;
- int oldsize = f->sizelocvars;
- luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars,
- LocVar, SHRT_MAX, "too many local variables");
- while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL;
- f->locvars[fs->nlocvars].varname = varname;
- luaC_objbarrier(ls->L, f, varname);
- return fs->nlocvars++;
- }
- #define new_localvarliteral(ls,v,n)
- new_localvar(ls, luaX_newstring(ls, "" v, (sizeof(v)/sizeof(char))-1), n)
- static void new_localvar (LexState *ls, TString *name, int n) {
- FuncState *fs = ls->fs;
- luaY_checklimit(fs, fs->nactvar+n+1, LUAI_MAXVARS, "local variables");
- fs->actvar[fs->nactvar+n] = cast(unsigned short, registerlocalvar(ls, name));
- }
- static void adjustlocalvars (LexState *ls, int nvars) {
- FuncState *fs = ls->fs;
- fs->nactvar = cast_byte(fs->nactvar + nvars);
- for (; nvars; nvars--) {
- getlocvar(fs, fs->nactvar - nvars).startpc = fs->pc;
- }
- }
- static void removevars (LexState *ls, int tolevel) {
- FuncState *fs = ls->fs;
- while (fs->nactvar > tolevel)
- getlocvar(fs, --fs->nactvar).endpc = fs->pc;
- }
- static int indexupvalue (FuncState *fs, TString *name, expdesc *v) {
- int i;
- Proto *f = fs->f;
- int oldsize = f->sizeupvalues;
- for (i=0; i<f->nups; i++) {
- if (fs->upvalues[i].k == v->k && fs->upvalues[i].info == v->u.s.info) {
- lua_assert(f->upvalues[i] == name);
- return i;
- }
- }
- /* new one */
- luaY_checklimit(fs, f->nups + 1, LUAI_MAXUPVALUES, "upvalues");
- luaM_growvector(fs->L, f->upvalues, f->nups, f->sizeupvalues,
- TString *, MAX_INT, "");
- while (oldsize < f->sizeupvalues) f->upvalues[oldsize++] = NULL;
- f->upvalues[f->nups] = name;
- luaC_objbarrier(fs->L, f, name);
- lua_assert(v->k == VLOCAL || v->k == VUPVAL);
- fs->upvalues[f->nups].k = cast_byte(v->k);
- fs->upvalues[f->nups].info = cast_byte(v->u.s.info);
- return f->nups++;
- }
- static int searchvar (FuncState *fs, TString *n) {
- int i;
- for (i=fs->nactvar-1; i >= 0; i--) {
- if (n == getlocvar(fs, i).varname)
- return i;
- }
- return -1; /* not found */
- }
- static void markupval (FuncState *fs, int level) {
- BlockCnt *bl = fs->bl;
- while (bl && bl->nactvar > level) bl = bl->previous;
- if (bl) bl->upval = 1;
- }
- static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
- if (fs == NULL) { /* no more levels? */
- init_exp(var, VGLOBAL, NO_REG); /* default is global variable */
- return VGLOBAL;
- }
- else {
- int v = searchvar(fs, n); /* look up at current level */
- if (v >= 0) {
- init_exp(var, VLOCAL, v);
- if (!base)
- markupval(fs, v); /* local will be used as an upval */
- return VLOCAL;
- }
- else { /* not found at current level; try upper one */
- if (singlevaraux(fs->prev, n, var, 0) == VGLOBAL)
- return VGLOBAL;
- var->u.s.info = indexupvalue(fs, n, var); /* else was LOCAL or UPVAL */
- var->k = VUPVAL; /* upvalue in this level */
- return VUPVAL;
- }
- }
- }
- static void singlevar (LexState *ls, expdesc *var) {
- TString *varname = str_checkname(ls);
- FuncState *fs = ls->fs;
- if (singlevaraux(fs, varname, var, 1) == VGLOBAL)
- var->u.s.info = luaK_stringK(fs, varname); /* info points to global name */
- }
- static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
- FuncState *fs = ls->fs;
- int extra = nvars - nexps;
- if (hasmultret(e->k)) {
- extra++; /* includes call itself */
- if (extra < 0) extra = 0;
- luaK_setreturns(fs, e, extra); /* last exp. provides the difference */
- if (extra > 1) luaK_reserveregs(fs, extra-1);
- }
- else {
- if (e->k != VVOID) luaK_exp2nextreg(fs, e); /* close last expression */
- if (extra > 0) {
- int reg = fs->freereg;
- luaK_reserveregs(fs, extra);
- luaK_nil(fs, reg, extra);
- }
- }
- }
- static void enterlevel (LexState *ls) {
- if (++ls->L->nCcalls > LUAI_MAXCCALLS)
- luaX_lexerror(ls, "chunk has too many syntax levels", 0);
- }
- #define leavelevel(ls) ((ls)->L->nCcalls--)
- static void enterblock (FuncState *fs, BlockCnt *bl, lu_byte isbreakable) {
- bl->breaklist = NO_JUMP;
- bl->isbreakable = isbreakable;
- bl->nactvar = fs->nactvar;
- bl->upval = 0;
- bl->previous = fs->bl;
- fs->bl = bl;
- lua_assert(fs->freereg == fs->nactvar);
- }
- static void leaveblock (FuncState *fs) {
- BlockCnt *bl = fs->bl;
- fs->bl = bl->previous;
- removevars(fs->ls, bl->nactvar);
- if (bl->upval)
- luaK_codeABC(fs, OP_CLOSE, bl->nactvar, 0, 0);
- lua_assert(!bl->isbreakable || !bl->upval); /* loops have no body */
- lua_assert(bl->nactvar == fs->nactvar);
- fs->freereg = fs->nactvar; /* free registers */
- luaK_patchtohere(fs, bl->breaklist);
- }
- static void pushclosure (LexState *ls, FuncState *func, expdesc *v) {
- FuncState *fs = ls->fs;
- Proto *f = fs->f;
- int oldsize = f->sizep;
- int i;
- luaM_growvector(ls->L, f->p, fs->np, f->sizep, Proto *,
- MAXARG_Bx, "constant table overflow");
- while (oldsize < f->sizep) f->p[oldsize++] = NULL;
- f->p[fs->np++] = func->f;
- luaC_objbarrier(ls->L, f, func->f);
- init_exp(v, VRELOCABLE, luaK_codeABx(fs, OP_CLOSURE, 0, fs->np-1));
- for (i=0; i<func->f->nups; i++) {
- OpCode o = (func->upvalues[i].k == VLOCAL) ? OP_MOVE : OP_GETUPVAL;
- luaK_codeABC(fs, o, 0, func->upvalues[i].info, 0);
- }
- }
- static void open_func (LexState *ls, FuncState *fs) {
- lua_State *L = ls->L;
- Proto *f = luaF_newproto(L);
- fs->f = f;
- fs->prev = ls->fs; /* linked list of funcstates */
- fs->ls = ls;
- fs->L = L;
- ls->fs = fs;
- fs->pc = 0;
- fs->lasttarget = -1;
- fs->jpc = NO_JUMP;
- fs->freereg = 0;
- fs->nk = 0;
- fs->np = 0;
- fs->nlocvars = 0;
- fs->nactvar = 0;
- fs->bl = NULL;
- f->source = ls->source;
- f->maxstacksize = 2; /* registers 0/1 are always valid */
- fs->h = luaH_new(L, 0, 0);
- /* anchor table of constants and prototype (to avoid being collected) */
- sethvalue2s(L, L->top, fs->h);
- incr_top(L);
- setptvalue2s(L, L->top, f);
- incr_top(L);
- }
- static void close_func (LexState *ls) {
- lua_State *L = ls->L;
- FuncState *fs = ls->fs;
- Proto *f = fs->f;
- removevars(ls, 0);
- luaK_ret(fs, 0, 0); /* final return */
- luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
- f->sizecode = fs->pc;
- luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, int);
- f->sizelineinfo = fs->pc;
- luaM_reallocvector(L, f->k, f->sizek, fs->nk, TValue);
- f->sizek = fs->nk;
- luaM_reallocvector(L, f->p, f->sizep, fs->np, Proto *);
- f->sizep = fs->np;
- luaM_reallocvector(L, f->locvars, f->sizelocvars, fs->nlocvars, LocVar);
- f->sizelocvars = fs->nlocvars;
- luaM_reallocvector(L, f->upvalues, f->sizeupvalues, f->nups, TString *);
- f->sizeupvalues = f->nups;
- lua_assert(luaG_checkcode(f));
- lua_assert(fs->bl == NULL);
- ls->fs = fs->prev;
- L->top -= 2; /* remove table and prototype from the stack */
- /* last token read was anchored in defunct function; must reanchor it */
- if (fs) anchor_token(ls);
- }
- Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, const char *name) {
- struct LexState lexstate;
- struct FuncState funcstate;
- lexstate.buff = buff;
- luaX_setinput(L, &lexstate, z, luaS_new(L, name));
- open_func(&lexstate, &funcstate);
- funcstate.f->is_vararg = VARARG_ISVARARG; /* main func. is always vararg */
- luaX_next(&lexstate); /* read first token */
- chunk(&lexstate);
- check(&lexstate, TK_EOS);
- close_func(&lexstate);
- lua_assert(funcstate.prev == NULL);
- lua_assert(funcstate.f->nups == 0);
- lua_assert(lexstate.fs == NULL);
- return funcstate.f;
- }
- /*============================================================*/
- /* GRAMMAR RULES */
- /*============================================================*/
- static void field (LexState *ls, expdesc *v) {
- /* field -> ['.' | ':'] NAME */
- FuncState *fs = ls->fs;
- expdesc key;
- luaK_exp2anyreg(fs, v);
- luaX_next(ls); /* skip the dot or colon */
- checkname(ls, &key);
- luaK_indexed(fs, v, &key);
- }
- static void yindex (LexState *ls, expdesc *v) {
- /* index -> '[' expr ']' */
- luaX_next(ls); /* skip the '[' */
- expr(ls, v);
- luaK_exp2val(ls->fs, v);
- checknext(ls, ']');
- }
- /*
- ** {======================================================================
- ** Rules for Constructors
- ** =======================================================================
- */
- struct ConsControl {
- expdesc v; /* last list item read */
- expdesc *t; /* table descriptor */
- int nh; /* total number of `record' elements */
- int na; /* total number of array elements */
- int tostore; /* number of array elements pending to be stored */
- };
- static void recfield (LexState *ls, struct ConsControl *cc) {
- /* recfield -> (NAME | `['exp1`]') = exp1 */
- FuncState *fs = ls->fs;
- int reg = ls->fs->freereg;
- expdesc key, val;
- if (ls->t.token == TK_NAME) {
- luaY_checklimit(fs, cc->nh, MAX_INT, "items in a constructor");
- checkname(ls, &key);
- }
- else /* ls->t.token == '[' */
- yindex(ls, &key);
- cc->nh++;
- checknext(ls, '=');
- luaK_exp2RK(fs, &key);
- expr(ls, &val);
- luaK_codeABC(fs, OP_SETTABLE, cc->t->u.s.info, luaK_exp2RK(fs, &key),
- luaK_exp2RK(fs, &val));
- fs->freereg = reg; /* free registers */
- }
- static void closelistfield (FuncState *fs, struct ConsControl *cc) {
- if (cc->v.k == VVOID) return; /* there is no list item */
- luaK_exp2nextreg(fs, &cc->v);
- cc->v.k = VVOID;
- if (cc->tostore == LFIELDS_PER_FLUSH) {
- luaK_setlist(fs, cc->t->u.s.info, cc->na, cc->tostore); /* flush */
- cc->tostore = 0; /* no more items pending */
- }
- }
- static void lastlistfield (FuncState *fs, struct ConsControl *cc) {
- if (cc->tostore == 0) return;
- if (hasmultret(cc->v.k)) {
- luaK_setmultret(fs, &cc->v);
- luaK_setlist(fs, cc->t->u.s.info, cc->na, LUA_MULTRET);
- cc->na--; /* do not count last expression (unknown number of elements) */
- }
- else {
- if (cc->v.k != VVOID)
- luaK_exp2nextreg(fs, &cc->v);
- luaK_setlist(fs, cc->t->u.s.info, cc->na, cc->tostore);
- }
- }
- static void listfield (LexState *ls, struct ConsControl *cc) {
- expr(ls, &cc->v);
- luaY_checklimit(ls->fs, 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) */
- checknext(ls, '{');
- do {
- lua_assert(cc.v.k == VVOID || cc.tostore > 0);
- if (ls->t.token == '}') break;
- closelistfield(fs, &cc);
- switch(ls->t.token) {
- case TK_NAME: { /* may be listfields or recfields */
- luaX_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);
- SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */
- SETARG_C(fs->f->code[pc], luaO_int2fb(cc.nh)); /* set initial table size */
- }
- /* }====================================================================== */
- static void parlist (LexState *ls) {
- /* parlist -> [ param { `,' param } ] */
- FuncState *fs = ls->fs;
- Proto *f = fs->f;
- int nparams = 0;
- f->is_vararg = 0;
- if (ls->t.token != ')') { /* is `parlist' not empty? */
- do {
- switch (ls->t.token) {
- case TK_NAME: { /* param -> NAME */
- new_localvar(ls, str_checkname(ls), nparams++);
- break;
- }
- case TK_DOTS: { /* param -> `...' */
- luaX_next(ls);
- #if defined(LUA_COMPAT_VARARG)
- /* use `arg' as default name */
- new_localvarliteral(ls, "arg", nparams++);
- f->is_vararg = VARARG_HASARG | VARARG_NEEDSARG;
- #endif
- f->is_vararg |= VARARG_ISVARARG;
- break;
- }
- default: luaX_syntaxerror(ls, "<name> or " LUA_QL("...") " expected");
- }
- } while (!f->is_vararg && testnext(ls, ','));
- }
- adjustlocalvars(ls, nparams);
- f->numparams = cast_byte(fs->nactvar - (f->is_vararg & VARARG_HASARG));
- luaK_reserveregs(fs, fs->nactvar); /* reserve register for parameters */
- }
- 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;
- checknext(ls, '(');
- if (needself) {
- new_localvarliteral(ls, "self", 0);
- adjustlocalvars(ls, 1);
- }
- parlist(ls);
- checknext(ls, ')');
- chunk(ls);
- new_fs.f->lastlinedefined = ls->linenumber;
- check_match(ls, TK_END, TK_FUNCTION, line);
- close_func(ls);
- pushclosure(ls, &new_fs, e);
- }
- static int explist1 (LexState *ls, expdesc *v) {
- /* explist1 -> expr { `,' expr } */
- int n = 1; /* at least one expression */
- expr(ls, v);
- while (testnext(ls, ',')) {
- luaK_exp2nextreg(ls->fs, v);
- expr(ls, v);
- n++;
- }
- return n;
- }
- static void funcargs (LexState *ls, expdesc *f) {
- FuncState *fs = ls->fs;
- expdesc args;
- int base, nparams;
- int line = ls->linenumber;
- switch (ls->t.token) {
- case '(': { /* funcargs -> `(' [ explist1 ] `)' */
- if (line != ls->lastline)
- luaX_syntaxerror(ls,"ambiguous syntax (function call x new statement)");
- luaX_next(ls);
- if (ls->t.token == ')') /* arg list is empty? */
- args.k = VVOID;
- else {
- explist1(ls, &args);
- luaK_setmultret(fs, &args);
- }
- check_match(ls, ')', '(', line);
- break;
- }
- case '{': { /* funcargs -> constructor */
- constructor(ls, &args);
- break;
- }
- case TK_STRING: { /* funcargs -> STRING */
- codestring(ls, &args, ls->t.seminfo.ts);
- luaX_next(ls); /* must use `seminfo' before `next' */
- break;
- }
- default: {
- luaX_syntaxerror(ls, "function arguments expected");
- return;
- }
- }
- lua_assert(f->k == VNONRELOC);
- base = f->u.s.info; /* base register for call */
- if (hasmultret(args.k))
- nparams = LUA_MULTRET; /* open call */
- else {
- if (args.k != VVOID)
- luaK_exp2nextreg(fs, &args); /* close last argument */
- nparams = fs->freereg - (base+1);
- }
- init_exp(f, VCALL, luaK_codeABC(fs, OP_CALL, base, nparams+1, 2));
- luaK_fixline(fs, line);
- fs->freereg = base+1; /* call remove function and arguments and leaves
- (unless changed) one result */
- }
- /*
- ** {======================================================================
- ** Expression parsing
- ** =======================================================================
- */
- static void prefixexp (LexState *ls, expdesc *v) {
- /* prefixexp -> NAME | '(' expr ')' */
- switch (ls->t.token) {
- case '(': {
- int line = ls->linenumber;
- luaX_next(ls);
- expr(ls, v);
- check_match(ls, ')', '(', line);
- luaK_dischargevars(ls->fs, v);
- return;
- }
- case TK_NAME: {
- singlevar(ls, v);
- 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 */
- field(ls, v);
- break;
- }
- case '[': { /* `[' exp1 `]' */
- expdesc key;
- luaK_exp2anyreg(fs, v);
- yindex(ls, &key);
- luaK_indexed(fs, v, &key);
- break;
- }
- case ':': { /* `:' NAME funcargs */
- expdesc key;
- luaX_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 | true | false | ... |
- constructor | FUNCTION body | primaryexp */
- switch (ls->t.token) {
- case TK_NUMBER: {
- init_exp(v, VKNUM, 0);
- v->u.nval = ls->t.seminfo.r;
- break;
- }
- case TK_STRING: {
- codestring(ls, v, ls->t.seminfo.ts);
- break;
- }
- case TK_NIL: {
- init_exp(v, VNIL, 0);
- break;
- }
- case TK_TRUE: {
- init_exp(v, VTRUE, 0);
- break;
- }
- case TK_FALSE: {
- init_exp(v, VFALSE, 0);
- break;
- }
- case TK_DOTS: { /* vararg */
- FuncState *fs = ls->fs;
- check_condition(ls, fs->f->is_vararg,
- "cannot use " LUA_QL("...") " outside a vararg function");
- fs->f->is_vararg &= ~VARARG_NEEDSARG; /* don't need 'arg' */
- init_exp(v, VVARARG, luaK_codeABC(fs, OP_VARARG, 0, 1, 0));
- break;
- }
- case '{': { /* constructor */
- constructor(ls, v);
- return;
- }
- case TK_FUNCTION: {
- luaX_next(ls);
- body(ls, v, 0, ls->linenumber);
- return;
- }
- default: {
- primaryexp(ls, v);
- return;
- }
- }
- luaX_next(ls);
- }
- static UnOpr getunopr (int op) {
- switch (op) {
- case TK_NOT: return OPR_NOT;
- case '-': return OPR_MINUS;
- case '#': return OPR_LEN;
- default: return OPR_NOUNOPR;
- }
- }
- static BinOpr getbinopr (int op) {
- switch (op) {
- case '+': return OPR_ADD;
- case '-': return OPR_SUB;
- case '*': return OPR_MUL;
- case '/': return OPR_DIV;
- case '%': return OPR_MOD;
- 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}, {7, 7}, /* `+' `-' `/' `%' */
- {10, 9}, {5, 4}, /* power and concat (right associative) */
- {3, 3}, {3, 3}, /* equality and inequality */
- {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 -> (simpleexp | unop subexpr) { binop subexpr }
- ** where `binop' is any binary operator with a priority higher than `limit'
- */
- static BinOpr subexpr (LexState *ls, expdesc *v, unsigned int limit) {
- BinOpr op;
- UnOpr uop;
- enterlevel(ls);
- uop = getunopr(ls->t.token);
- if (uop != OPR_NOUNOPR) {
- luaX_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 && priority[op].left > limit) {
- expdesc v2;
- BinOpr nextop;
- luaX_next(ls);
- luaK_infix(ls->fs, op, v);
- /* read sub-expression with higher priority */
- nextop = subexpr(ls, &v2, priority[op].right);
- luaK_posfix(ls->fs, op, v, &v2);
- op = nextop;
- }
- leavelevel(ls);
- return op; /* return first untreated operator */
- }
- static void expr (LexState *ls, expdesc *v) {
- subexpr(ls, v, 0);
- }
- /* }==================================================================== */
- /*
- ** {======================================================================
- ** 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.u.s.info == v->u.s.info) { /* conflict? */
- conflict = 1;
- lh->v.u.s.info = extra; /* previous assignment will use safe copy */
- }
- if (lh->v.u.s.aux == v->u.s.info) { /* conflict? */
- conflict = 1;
- lh->v.u.s.aux = extra; /* previous assignment will use safe copy */
- }
- }
- }
- if (conflict) {
- luaK_codeABC(fs, OP_MOVE, fs->freereg, v->u.s.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;
- checknext(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_setoneret(ls->fs, &e); /* 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 int cond (LexState *ls) {
- /* cond -> exp */
- expdesc v;
- expr(ls, &v); /* read condition */
- if (v.k == VNIL) v.k = VFALSE; /* `falses' are all equal here */
- luaK_goiftrue(ls->fs, &v);
- return v.f;
- }
- static void breakstat (LexState *ls) {
- FuncState *fs = ls->fs;
- BlockCnt *bl = fs->bl;
- int upval = 0;
- 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 void whilestat (LexState *ls, int line) {
- /* whilestat -> WHILE cond DO block END */
- FuncState *fs = ls->fs;
- int whileinit;
- int condexit;
- BlockCnt bl;
- luaX_next(ls); /* skip WHILE */
- whileinit = luaK_getlabel(fs);
- condexit = cond(ls);
- enterblock(fs, &bl, 1);
- checknext(ls, TK_DO);
- block(ls);
- luaK_patchlist(fs, luaK_jump(fs), whileinit);
- check_match(ls, TK_END, TK_WHILE, line);
- leaveblock(fs);
- luaK_patchtohere(fs, condexit); /* false conditions finish the loop */
- }
- static void repeatstat (LexState *ls, int line) {
- /* repeatstat -> REPEAT block UNTIL cond */
- int condexit;
- FuncState *fs = ls->fs;
- int repeat_init = luaK_getlabel(fs);
- BlockCnt bl1, bl2;
- enterblock(fs, &bl1, 1); /* loop block */
- enterblock(fs, &bl2, 0); /* scope block */
- luaX_next(ls); /* skip REPEAT */
- chunk(ls);
- check_match(ls, TK_UNTIL, TK_REPEAT, line);
- condexit = cond(ls); /* read condition (inside scope block) */
- if (!bl2.upval) { /* no upvalues? */
- leaveblock(fs); /* finish scope */
- luaK_patchlist(ls->fs, condexit, repeat_init); /* close the loop */
- }
- else { /* complete semantics when there are upvalues */
- breakstat(ls); /* if condition then break */
- luaK_patchtohere(ls->fs, condexit); /* else... */
- leaveblock(fs); /* finish scope... */
- luaK_patchlist(ls->fs, luaK_jump(fs), repeat_init); /* and repeat */
- }
- leaveblock(fs); /* finish loop */
- }
- static int exp1 (LexState *ls) {
- expdesc e;
- int k;
- expr(ls, &e);
- k = e.k;
- luaK_exp2nextreg(ls->fs, &e);
- return k;
- }
- static void forbody (LexState *ls, int base, int line, int nvars, int isnum) {
- /* forbody -> DO block */
- BlockCnt bl;
- FuncState *fs = ls->fs;
- int prep, endfor;
- adjustlocalvars(ls, 3); /* control variables */
- checknext(ls, TK_DO);
- prep = isnum ? luaK_codeAsBx(fs, OP_FORPREP, base, NO_JUMP) : luaK_jump(fs);
- enterblock(fs, &bl, 0); /* scope for declared variables */
- adjustlocalvars(ls, nvars);
- luaK_reserveregs(fs, nvars);
- block(ls);
- leaveblock(fs); /* end of scope for declared variables */
- luaK_patchtohere(fs, prep);
- endfor = (isnum) ? luaK_codeAsBx(fs, OP_FORLOOP, base, NO_JUMP) :
- luaK_codeABC(fs, OP_TFORLOOP, base, 0, nvars);
- luaK_fixline(fs, line); /* pretend that `OP_FOR' starts the loop */
- luaK_patchlist(fs, (isnum ? endfor : luaK_jump(fs)), prep + 1);
- }
- static void fornum (LexState *ls, TString *varname, int line) {
- /* fornum -> NAME = exp1,exp1[,exp1] forbody */
- FuncState *fs = ls->fs;
- int base = fs->freereg;
- new_localvarliteral(ls, "(for index)", 0);
- new_localvarliteral(ls, "(for limit)", 1);
- new_localvarliteral(ls, "(for step)", 2);
- new_localvar(ls, varname, 3);
- checknext(ls, '=');
- exp1(ls); /* initial value */
- checknext(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);
- }
- forbody(ls, base, line, 1, 1);
- }
- static void forlist (LexState *ls, TString *indexname) {
- /* forlist -> NAME {,NAME} IN explist1 forbody */
- FuncState *fs = ls->fs;
- expdesc e;
- int nvars = 0;
- int line;
- int base = fs->freereg;
- /* create control variables */
- new_localvarliteral(ls, "(for generator)", nvars++);
- new_localvarliteral(ls, "(for state)", nvars++);
- new_localvarliteral(ls, "(for control)", nvars++);
- /* create declared variables */
- new_localvar(ls, indexname, nvars++);
- while (testnext(ls, ','))
- new_localvar(ls, str_checkname(ls), nvars++);
- checknext(ls, TK_IN);
- line = ls->linenumber;
- adjust_assign(ls, 3, explist1(ls, &e), &e);
- luaK_checkstack(fs, 3); /* extra space to call generator */
- forbody(ls, base, line, nvars - 3, 0);
- }
- static void forstat (LexState *ls, int line) {
- /* forstat -> FOR (fornum | forlist) END */
- FuncState *fs = ls->fs;
- TString *varname;
- BlockCnt bl;
- enterblock(fs, &bl, 1); /* scope for loop and control variables */
- luaX_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, LUA_QL("=") " or " LUA_QL("in") " expected");
- }
- check_match(ls, TK_END, TK_FOR, line);
- leaveblock(fs); /* loop scope (`break' jumps to this point) */
- }
- static int test_then_block (LexState *ls) {
- /* test_then_block -> [IF | ELSEIF] cond THEN block */
- int condexit;
- luaX_next(ls); /* skip IF or ELSEIF */
- condexit = cond(ls);
- checknext(ls, TK_THEN);
- block(ls); /* `then' part */
- return condexit;
- }
- static void ifstat (LexState *ls, int line) {
- /* ifstat -> IF cond THEN block {ELSEIF cond THEN block} [ELSE block] END */
- FuncState *fs = ls->fs;
- int flist;
- int escapelist = NO_JUMP;
- flist = test_then_block(ls); /* IF cond THEN block */
- while (ls->t.token == TK_ELSEIF) {
- luaK_concat(fs, &escapelist, luaK_jump(fs));
- luaK_patchtohere(fs, flist);
- flist = test_then_block(ls); /* ELSEIF cond THEN block */
- }
- if (ls->t.token == TK_ELSE) {
- luaK_concat(fs, &escapelist, luaK_jump(fs));
- luaK_patchtohere(fs, flist);
- luaX_next(ls); /* skip ELSE (after patch, for correct line info) */
- block(ls); /* `else' part */
- }
- else
- luaK_concat(fs, &escapelist, flist);
- luaK_patchtohere(fs, escapelist);
- check_match(ls, TK_END, TK_IF, line);
- }
- static void localfunc (LexState *ls) {
- expdesc v, b;
- FuncState *fs = ls->fs;
- new_localvar(ls, str_checkname(ls), 0);
- init_exp(&v, VLOCAL, fs->freereg);
- luaK_reserveregs(fs, 1);
- adjustlocalvars(ls, 1);
- body(ls, &b, 0, ls->linenumber);
- luaK_storevar(fs, &v, &b);
- /* debug information will only see the variable after this point! */
- getlocvar(fs, fs->nactvar - 1).startpc = fs->pc;
- }
- 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);
- while (ls->t.token == '.')
- field(ls, v);
- if (ls->t.token == ':') {
- needself = 1;
- field(ls, v);
- }
- return needself;
- }
- static void funcstat (LexState *ls, int line) {
- /* funcstat -> FUNCTION funcname body */
- int needself;
- expdesc v, b;
- luaX_next(ls); /* skip FUNCTION */
- needself = funcname(ls, &v);
- body(ls, &b, needself, line);
- luaK_storevar(ls->fs, &v, &b);
- luaK_fixline(ls->fs, line); /* definition `happens' in the first line */
- }
- 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 */
- SETARG_C(getcode(fs, &v.v), 1); /* 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 */
- luaX_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 (hasmultret(e.k)) {
- luaK_setmultret(fs, &e);
- if (e.k == VCALL && 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_ret(fs, first, nret);
- }
- 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 */
- luaX_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 */
- luaX_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 */
- luaX_next(ls); /* skip BREAK */
- breakstat(ls);
- return 1; /* must be last statement */
- }
- default: {
- exprstat(ls);
- return 0; /* to avoid warnings */
- }
- }
- }
- static void chunk (LexState *ls) {
- /* chunk -> { stat [`;'] } */
- int islast = 0;
- enterlevel(ls);
- while (!islast && !block_follow(ls->t.token)) {
- islast = statement(ls);
- testnext(ls, ';');
- lua_assert(ls->fs->f->maxstacksize >= ls->fs->freereg &&
- ls->fs->freereg >= ls->fs->nactvar);
- ls->fs->freereg = ls->fs->nactvar; /* free registers */
- }
- leavelevel(ls);
- }
- /* }====================================================================== */