It would be good to add the name of the parser to the _stamp_. Because knowing a parser failed parsing an input but not knowing which one is in theory useless (even if in practice we will guess which one).

Unfortunately there is nothing convenient in place to identify easily the parser. Here are the quick solutions: 

* instead of creating some parsers by __using__ the `Parser` class, always __extend__ the latter and provide a custom name
* otherwise add a `name`/`language` or more sophisticated [taxonomy](http://en.wikipedia.org/wiki/Taxonomy) property to the `Parser` class (and provide it at instantiation)
* trust files layouts and extract from the path of the parser module the name of the mode's folder

By the way, I don't think specifying `utf-8` is required for writing, it is used by default.