Read member flags
@return array
1st index : 0 => public, 1 => protected, 2 => private
2nd index : 0 => instance member, 1 => static member
3rd index : 0 => normal, 1 => abstract member, 2 => final member
function(asInterface) {
    const result = [-1, -1, -1];
    if (this.is("T_MEMBER_FLAGS")) {
      let idx = 0,
        val = 0;
      do {
        switch (this.token) {
          case this.tok.T_PUBLIC:
            idx = 0;
            val = 0;
            break;
          case this.tok.T_PROTECTED:
            idx = 0;
            val = 1;
            break;
          case this.tok.T_PRIVATE:
            idx = 0;
            val = 2;
            break;
          case this.tok.T_STATIC:
            idx = 1;
            val = 1;
            break;
          case this.tok.T_ABSTRACT:
            idx = 2;
            val = 1;
            break;
          case this.tok.T_FINAL:
            idx = 2;
            val = 2;
            break;
        }
        if (asInterface) {
          if (idx == 0 && val == 2) {
            // an interface can't be private
            this.expect([this.tok.T_PUBLIC, this.tok.T_PROTECTED]);
            val = -1;
          } else if (idx == 2 && val == 1) {
            // an interface cant be abstract
            this.error();
            val = -1;
          }
        }
        if (result[idx] !== -1) {
          // already defined flag
          this.error();
        } else if (val !== -1) {
          result[idx] = val;
        }
      } while (this.next().is("T_MEMBER_FLAGS"));
    }

    if (result[1] == -1) result[1] = 0;
    if (result[2] == -1) result[2] = 0;
    return result;
  }