diff options
Diffstat (limited to 'src/lparser.c')
| -rw-r--r-- | src/lparser.c | 1339 |
1 files changed, 1339 insertions, 0 deletions
diff --git a/src/lparser.c b/src/lparser.c new file mode 100644 index 0000000..1e2a9a8 --- /dev/null +++ b/src/lparser.c @@ -0,0 +1,1339 @@ +/* +** $Id: lparser.c,v 2.42.1.3 2007/12/28 15:32:23 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" +#include "ltable.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); + /* a block either controls scope or breaks (never both) */ + lua_assert(!bl->isbreakable || !bl->upval); + 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; + int rkkey; + 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, '='); + rkkey = luaK_exp2RK(fs, &key); + expr(ls, &val); + luaK_codeABC(fs, OP_SETTABLE, cc->t->u.s.info, rkkey, 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, MAX_INT, "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); + luaY_checklimit(ls->fs, nvars, LUAI_MAXCCALLS - ls->L->nCcalls, + "variables in assignment"); + 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); +} + +/* }====================================================================== */ |