I've noticed that the `StandardFormatter` was quite bloated, which made
it difficult to maintain. Understanding what each method was doing was
quite complicated. Besides, the name "Standard" doesn't mean anything,
because it doesn't say what the implementation does.
I split the `Formatter` into two different interfaces: `StringFormatter`
and `ArrayFormatter`, and I moved some code around:
* `StandardFormatter::main()` -> `FirstResultStringFormatter`
* `StandardFormatter::full()` -> `NestedListStringFormatter`
* `StandardFormatter::array()` -> `NestedArrayFormatter`
That opens up new ways of handling error messages, potentially
introducing features like `JsonStringFormatter` or `FlatArrayFormatter`
in the future.
While working on this, I removed a significant amount of unnecessary
code, which also improved my overall understanding of those formatters.
I'm not very happy with all the methods in `ValidatorDefaults`, but I
will refactor that later.
I've already changed the `ValidationException` so as not to let the file
and line from the Validator.php [1]. However, one could go even further
when creating more customizations on top of this library, and allowing
to customize the line could be very useful.
What motivated me making this change because it will be handy when I get
back to work on [Assertion][].
[1]: 75a9b8e94f
[Assertion]: https://github.com/Respect/Assertion
Currently, defining translations is quite cumbersome, and the translator
callback is passed to the constructor of multiple classes, which makes
it quite ugly and could make translations inconsistent.
This commit completely changes how translations are done in Validation.
Instead of using a callback, it uses a specific class, and `Validator`
will pass that object through the objects that render the messages.
