anchor.diff:        return {
           "type": "return",
           "value": statement.expression != null ? _generateExpression(statement.expression) : null
  +      };
  +    } else if (statement is MultiAssignment) {
  +      return {
  +        "type": "multiple assignment",
  +        "ids": statement.ids,
  +        "immutable": statement.immutable,
  +        "isNullable": statement.isNullable,
  +        "isInitialDefine": statement.isInitialDefine,
  +        "value": _generateExpression(statement.value)
         };
       } else if (statement is BreakStatement) {
         return {
  
positive.code:     "isNullable": "(",
      "location": ")",
      "parts": "?",
      "extension": "_"
    };
  
    static String demap(String key) {
  
negative.code:         _buildExpression(it["value"]),
          new Block(it["block"].map(_buildStatement).toList())
        );
      } else if (type == "multiple assignment") {
        return new MultiAssignment(it["ids"], _buildExpression(it["value"]), it["immutable"], it["isInitialDefine"], it["isNullable"]);
      } else if (type == "type") {
        return new TypeBlock(
          it["name"],
  