lua/lparser.c

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/*
** $Id: lparser.c,v 1.3 2004/03/23 05:09:14 jbj Exp $
** Lua Parser
** See Copyright Notice in lua.h
*/


#include <string.h>

#define lparser_c

#include "lua.h"

#include "lcode.h"
#include "ldebug.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 getlocvar(fs, i)        ((fs)->f->locvars[(fs)->actvar[i]])


#define enterlevel(ls)  if (++(ls)->nestlevel > LUA_MAXPARSERLEVEL) \
                luaX_syntaxerror(ls, "too many syntax levels");
#define leavelevel(ls)  ((ls)->nestlevel--)


/*
** nodes for block list (list of active blocks)
*/
typedef struct BlockCnt {
/*@null@*/
  struct BlockCnt *previous;  /* chain */
  int breaklist;  /* list of jumps out of this loop */
  int nactvar;  /* # active local variables outside the breakable structure */
  int upval;  /* true if some variable in the block is an upvalue */
  int isbreakable;  /* true if `block' is a loop */
} BlockCnt;



/*
** prototypes for recursive non-terminal functions
*/
static void chunk (LexState *ls)
        /*@modifies ls @*/;
static void expr (LexState *ls, expdesc *v)
        /*@modifies ls, v @*/;



static void next (LexState *ls)
        /*@modifies ls @*/
{
  ls->lastline = ls->linenumber;
  if (ls->lookahead.token != TK_EOS) {  /* is there a look-ahead token? */
    ls->t = ls->lookahead;  /* use this one */
    ls->lookahead.token = TK_EOS;  /* and discharge it */
  }
  else
    ls->t.token = luaX_lex(ls, &ls->t.seminfo);  /* read next token */
}


static void lookahead (LexState *ls)
        /*@modifies ls @*/
{
  lua_assert(ls->lookahead.token == TK_EOS);
  ls->lookahead.token = luaX_lex(ls, &ls->lookahead.seminfo);
}


static void error_expected (LexState *ls, int token)
        /*@modifies ls @*/
{
  luaX_syntaxerror(ls,
         luaO_pushfstring(ls->L, "`%s' expected", luaX_token2str(ls, token)));
}


static int testnext (LexState *ls, int c)
        /*@modifies ls @*/
{
  if (ls->t.token == c) {
    next(ls);
    return 1;
  }
  else return 0;
}


static void check (LexState *ls, int c)
        /*@modifies ls @*/
{
  if (!testnext(ls, c))
    error_expected(ls, c);
}


#define check_condition(ls,c,msg)       { if (!(c)) luaX_syntaxerror(ls, msg); }



static void check_match (LexState *ls, int what, int who, int where)
        /*@modifies ls @*/
{
  if (!testnext(ls, what)) {
    if (where == ls->linenumber)
      error_expected(ls, what);
    else {
      luaX_syntaxerror(ls, luaO_pushfstring(ls->L,
             "`%s' expected (to close `%s' at line %d)",
              luaX_token2str(ls, what), luaX_token2str(ls, who), where));
    }
  }
}


static TString *str_checkname (LexState *ls)
        /*@modifies ls @*/
{
  TString *ts;
  check_condition(ls, (ls->t.token == TK_NAME), "<name> expected");
  ts = ls->t.seminfo.ts;
  next(ls);
  return ts;
}


static void init_exp (expdesc *e, expkind k, int i)
        /*@modifies e @*/
{
  e->f = e->t = NO_JUMP;
  e->k = k;
  e->info = i;
}


static void codestring (LexState *ls, expdesc *e, TString *s)
        /*@modifies ls, e @*/
{
  init_exp(e, VK, luaK_stringK(ls->fs, s));
}


static void checkname(LexState *ls, expdesc *e)
        /*@modifies ls, e @*/
{
  codestring(ls, e, str_checkname(ls));
}


static int luaI_registerlocalvar (LexState *ls, TString *varname)
        /*@modifies ls @*/
{
  FuncState *fs = ls->fs;
  Proto *f = fs->f;
  luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars,
                  LocVar, MAX_INT, "");
  f->locvars[fs->nlocvars].varname = varname;
  return fs->nlocvars++;
}


static void new_localvar (LexState *ls, TString *name, int n)
        /*@modifies ls @*/
{
  FuncState *fs = ls->fs;
  luaX_checklimit(ls, fs->nactvar+n+1, MAXVARS, "local variables");
  fs->actvar[fs->nactvar+n] = luaI_registerlocalvar(ls, name);
}


static void adjustlocalvars (LexState *ls, int nvars)
        /*@modifies ls @*/
{
  FuncState *fs = ls->fs;
  fs->nactvar += nvars;
  for (; nvars; nvars--) {
    getlocvar(fs, fs->nactvar - nvars).startpc = fs->pc;
  }
}


static void removevars (LexState *ls, int tolevel)
        /*@modifies ls @*/
{
  FuncState *fs = ls->fs;
  while (fs->nactvar > tolevel)
    getlocvar(fs, --fs->nactvar).endpc = fs->pc;
}


static void new_localvarstr (LexState *ls, const char *name, int n)
        /*@modifies ls @*/
{
  new_localvar(ls, luaS_new(ls->L, name), n);
}


static void create_local (LexState *ls, const char *name)
        /*@modifies ls @*/
{
  new_localvarstr(ls, name, 0);
  adjustlocalvars(ls, 1);
}


static int indexupvalue (FuncState *fs, TString *name, expdesc *v)
        /*@modifies fs @*/
{
  int i;
  Proto *f = fs->f;
  for (i=0; i<f->nups; i++) {
    if (fs->upvalues[i].k == v->k && fs->upvalues[i].info == v->info) {
      lua_assert(fs->f->upvalues[i] == name);
      return i;
    }
  }
  /* new one */
  luaX_checklimit(fs->ls, f->nups + 1, MAXUPVALUES, "upvalues");
  luaM_growvector(fs->L, fs->f->upvalues, f->nups, fs->f->sizeupvalues,
                  TString *, MAX_INT, "");
  fs->f->upvalues[f->nups] = name;
  fs->upvalues[f->nups] = *v;
  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)
        /*@modifies fs @*/
{
  BlockCnt *bl = fs->bl;
  while (bl && bl->nactvar > level) bl = bl->previous;
  if (bl) bl->upval = 1;
}


static void singlevaraux (FuncState *fs, TString *n, expdesc *var, int base)
        /*@modifies fs, var @*/
{
  if (fs == NULL)  /* no more levels? */
    init_exp(var, VGLOBAL, NO_REG);  /* default is global variable */
  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 */
    }
    else {  /* not found at current level; try upper one */
      singlevaraux(fs->prev, n, var, 0);
      if (var->k == VGLOBAL) {
        if (base)
          var->info = luaK_stringK(fs, n);  /* info points to global name */
      }
      else {  /* LOCAL or UPVAL */
        var->info = indexupvalue(fs, n, var);
        var->k = VUPVAL;  /* upvalue in this level */
      }
    }
  }
}


static TString *singlevar (LexState *ls, expdesc *var, int base)
        /*@modifies ls, var @*/
{
  TString *varname = str_checkname(ls);
  singlevaraux(ls->fs, varname, var, base);
  return varname;
}


static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e)
        /*@modifies ls, e @*/
{
  FuncState *fs = ls->fs;
  int extra = nvars - nexps;
  if (e->k == VCALL) {
    extra++;  /* includes call itself */
    if (extra <= 0) extra = 0;
    else luaK_reserveregs(fs, extra-1);
    luaK_setcallreturns(fs, e, extra);  /* call provides the difference */
  }
  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 code_params (LexState *ls, int nparams, int dots)
        /*@modifies ls @*/
{
  FuncState *fs = ls->fs;
  adjustlocalvars(ls, nparams);
  luaX_checklimit(ls, fs->nactvar, MAXPARAMS, "parameters");
  fs->f->numparams = cast(lu_byte, fs->nactvar);
  fs->f->is_vararg = cast(lu_byte, dots);
  if (dots)
    create_local(ls, "arg");
  luaK_reserveregs(fs, fs->nactvar);  /* reserve register for parameters */
}


static void enterblock (FuncState *fs, BlockCnt *bl, int isbreakable)
        /*@modifies fs, bl @*/
{
  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)
        /*@modifies 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->nactvar == fs->nactvar);
  fs->freereg = fs->nactvar;  /* free registers */
  luaK_patchtohere(fs, bl->breaklist);
}


static void pushclosure (LexState *ls, FuncState *func, expdesc *v)
        /*@modifies ls, v @*/
{
  FuncState *fs = ls->fs;
  Proto *f = fs->f;
  int i;
  luaM_growvector(ls->L, f->p, fs->np, f->sizep, Proto *,
                  MAXARG_Bx, "constant table overflow");
/*@-onlytrans@*/
  f->p[fs->np++] = func->f;
/*@=onlytrans@*/
  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)
        /*@modifies ls, fs @*/
{
  Proto *f = luaF_newproto(ls->L);
  fs->f = f;
  fs->prev = ls->fs;  /* linked list of funcstates */
  fs->ls = ls;
  fs->L = ls->L;
  ls->fs = fs;
  fs->pc = 0;
  fs->lasttarget = 0;
  fs->jpc = NO_JUMP;
  fs->freereg = 0;
  fs->nk = 0;
  fs->h = luaH_new(ls->L, 0, 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 */
}


static void close_func (LexState *ls)
        /*@modifies ls @*/
{
  lua_State *L = ls->L;
  FuncState *fs = ls->fs;
  Proto *f = fs->f;
  removevars(ls, 0);
  luaK_codeABC(fs, OP_RETURN, 0, 1, 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, TObject);
  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;
}


Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff) {
  struct LexState lexstate;
  struct FuncState funcstate;
  lexstate.buff = buff;
  lexstate.nestlevel = 0;
  luaX_setinput(L, &lexstate, z, luaS_new(L, zname(z)));
  open_func(&lexstate, &funcstate);
  next(&lexstate);  /* read first token */
  chunk(&lexstate);
  check_condition(&lexstate, (lexstate.t.token == TK_EOS), "<eof> expected");
  close_func(&lexstate);
  lua_assert(funcstate.prev == NULL);
  lua_assert(funcstate.f->nups == 0);
  lua_assert(lexstate.nestlevel == 0);
  return funcstate.f;
}



/*============================================================*/
/* GRAMMAR RULES */
/*============================================================*/


static void luaY_field (LexState *ls, expdesc *v)
        /*@modifies ls, v @*/
{
  /* field -> ['.' | ':'] NAME */
  FuncState *fs = ls->fs;
  expdesc key;
  luaK_exp2anyreg(fs, v);
  next(ls);  /* skip the dot or colon */
  checkname(ls, &key);
  luaK_indexed(fs, v, &key);
}


static void luaY_index (LexState *ls, expdesc *v)
        /*@modifies ls, v @*/
{
  /* index -> '[' expr ']' */
  next(ls);  /* skip the '[' */
  expr(ls, v);
  luaK_exp2val(ls->fs, v);
  check(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)
        /*@modifies ls, cc @*/
{
  /* recfield -> (NAME | `['exp1`]') = exp1 */
  FuncState *fs = ls->fs;
  int reg = ls->fs->freereg;
  expdesc key, val;
  if (ls->t.token == TK_NAME) {
    luaX_checklimit(ls, cc->nh, MAX_INT, "items in a constructor");
    cc->nh++;
    checkname(ls, &key);
  }
  else  /* ls->t.token == '[' */
    luaY_index(ls, &key);
  check(ls, '=');
  luaK_exp2RK(fs, &key);
  expr(ls, &val);
  luaK_codeABC(fs, OP_SETTABLE, cc->t->info, luaK_exp2RK(fs, &key),
                                             luaK_exp2RK(fs, &val));
  fs->freereg = reg;  /* free registers */
}


static void closelistfield (FuncState *fs, struct ConsControl *cc)
        /*@modifies fs, 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_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)
        /*@modifies fs, 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)
        /*@modifies ls, 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)
        /*@modifies ls, 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);
  SETARG_B(fs->f->code[pc], luaO_int2fb(cc.na)); /* set initial array size */
  SETARG_C(fs->f->code[pc], luaO_log2(cc.nh)+1);  /* set initial table size */
}

/* }====================================================================== */



static void parlist (LexState *ls)
        /*@modifies 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)
        /*@modifies ls, e @*/
{
  /* 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 int explist1 (LexState *ls, expdesc *v)
        /*@modifies ls, 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)
        /*@modifies ls, 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)");
      next(ls);
      if (ls->t.token == ')')  /* arg list is empty? */
        args.k = VVOID;
      else {
        explist1(ls, &args);
        luaK_setcallreturns(fs, &args, LUA_MULTRET);
      }
      check_match(ls, ')', '(', line);
      break;
    }
    case '{': {  /* funcargs -> constructor */
      constructor(ls, &args);
      break;
    }
    case TK_STRING: {  /* funcargs -> STRING */
      codestring(ls, &args, ls->t.seminfo.ts);
      next(ls);  /* must use `seminfo' before `next' */
      break;
    }
    default: {
      luaX_syntaxerror(ls, "function arguments expected");
      return;
    }
  }
  lua_assert(f->k == VNONRELOC);
  base = f->info;  /* base register for call */
  if (args.k == VCALL)
    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)
        /*@modifies ls, 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;
    }
#ifdef LUA_COMPATUPSYNTAX
    case '%': {  /* for compatibility only */
      TString *varname;
      int line = ls->linenumber;
      next(ls);  /* skip `%' */
      varname = singlevar(ls, v, 1);
      if (v->k != VUPVAL)
        luaX_errorline(ls, "global upvalues are obsolete",
                           getstr(varname), line);
      return;
    }
#endif
    default: {
      luaX_syntaxerror(ls, "unexpected symbol");
      return;
    }
  }
}


static void primaryexp (LexState *ls, expdesc *v)
        /*@modifies ls, 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)
        /*@modifies ls, 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