anchor.diff:  
       });
       test('.11', () {
  -      regex.RegexVM vm = new regex.RegexVM.createFromCommand(builder.done());
  +      regex.RegexVM vm = new regex.RegexVM.createFromCommand(number.done());
         print(vm.toString());
         return vm.lookingAt(conv.UTF8.encode(".11")).then((List<List<int>> v) {
           expect(conv.UTF8.decode(v[0]),"");
  
positive.code:         expect(true, false);
        });
      });
      regex.RegexBuilder builder = new regex.RegexBuilder();
      builder
      .push(true)
      .addRegexCommand(new regex.CharCommand.createFromList(conv.UTF8.encode("+")))
      .or()
  
negative.code:         expect(true, false);
        });
      });
      
      regex.RegexBuilder hexNumber = new regex.RegexBuilder();
      hexNumber
      .push(true)
      .addRegexCommand(new regex.CharCommand.createFromList(conv.UTF8.encode("+")))
      .or()
      .addRegexCommand(new regex.CharCommand.createFromList(conv.UTF8.encode("-")))
      .or()
      .addRegexCommand(new regex.EmptyCommand())
      .pop()
      .addRegexCommand(new regex.CharCommand.createFromList(conv.UTF8.encode("0x")))
      .push(true)
      .addRegexLeaf(new regex.StarPattern.fromCommand(
          new regex.MatchByteCommand([
            0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,
            0x61,0x62,0x63,0x64,0x65,0x66,
            0x41,0x42,0x43,0x44,0x45,0x46
            ])))
      .or()
      .addRegexCommand(new regex.EmptyCommand())
      .pop()
      .push(true)
      .addRegexCommand(new regex.CharCommand.createFromList(conv.UTF8.encode(".")))
      .or()
      .addRegexCommand(new regex.EmptyCommand())
      .pop()
      .push(true)
      .addRegexLeaf(new regex.StarPattern.fromCommand(
          new regex.MatchByteCommand([
            0x30,0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38,0x39,
            0x61,0x62,0x63,0x64,0x65,0x66,
            0x41,0x42,0x43,0x44,0x45,0x46
            ])))
      .or()
      .addRegexCommand(new regex.EmptyCommand())
      .pop();
      test('+0x1000.11', () {
        regex.RegexVM vm = new regex.RegexVM.createFromCommand(number.done());
  
        print(vm.toString());
        return vm.lookingAt(conv.UTF8.encode("+1000.11")).then((List<List<int>> v) {
          expect(conv.UTF8.decode(v[0]),"+");
          expect(conv.UTF8.decode(v[1]),"1000");
          expect(conv.UTF8.decode(v[2]),".");
          expect(conv.UTF8.decode(v[3]),"11");
        }).catchError((e) {
          expect(true, false);
        });
  
      });
    });
  }
  
  