Ejemplo n.º 1
0
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;
    }
  }
}
Ejemplo n.º 2
0
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;
      }
#if LUA_WIDESTRING
      case '(': case TK_STRING: case TK_WSTRING: case '{': {  /* funcargs */
#else
      case '(': case TK_STRING: case '{': {  /* funcargs */
#endif /* LUA_WIDESTRING */
        luaK_exp2nextreg(fs, v);
        funcargs(ls, v);
        break;
      }
      default: return;
    }
  }
}


static void simpleexp (LexState *ls, expdesc *v) {
#if LUA_WIDESTRING
  /* simpleexp -> NUMBER | STRING | WSTRING | NIL | true | false | ... |
                  constructor | FUNCTION body | primaryexp */
#else
  /* simpleexp -> NUMBER | STRING | NIL | true | false | ... |
                  constructor | FUNCTION body | primaryexp */
#endif /* LUA_WIDESTRING */
  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;
    }
#if LUA_WIDESTRING
    case TK_WSTRING: {
      codewstring(ls, v, ls->t.seminfo.ts);
      break;
    }
#endif /* LUA_WIDESTRING */
    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;
#if LUA_BITFIELD_OPS
    case '&': return OPR_BAND;
    case '|': return OPR_BOR;
    case TK_XOR: return OPR_BXOR;
    case TK_SHL: return OPR_BSHL;
    case TK_SHR: return OPR_BSHR;
#endif /* LUA_BITFIELD_OPS */
    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 */
#if LUA_BITFIELD_OPS
   {8, 8}, {8, 8}, {8, 8}, {8, 8}, {8, 8},  /* bitwise operators */
#endif /* LUA_BITFIELD_OPS */
   {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 */
}