Key reform

[tomassedovic]

This fixes #184 because of which we couldn't access certain keys. The KeyState struct is renamed to Key and has fields code and printable that correspond to libtcod's vk and c.

This also adds two convenience fields: alt and ctrl that are true if the left or right variant is pressed.

This is a breaking change. To update your code, convert it to match on the Key struct. I.e. replace this:

match keypress.key {
    Special(Enter) if keypress.left_alt => { // fullscreen }
    Special(Escape) => { // exit game }
    Key::Printable('>') => { // descend }
}

with this:

match keypress {
    Key { code: Enter, alt: true, .. } => { // fullscreen }
    Key { code: Escape, .. } => { // exit game }
    Key { printable: '>', .. } => { // descend }
}

[zsparal]

I like it. My only complaint with the current design is that matching an event is ridiculous:

match event {
    Some(_, Event::Key(Key { code: Enter, .. })) => {},
}

That' s a lot of noise for nothing, but I don't think it's solvable in current Rust. Ideally I'd like to be able to do something like this:

match event { 
    Some(_, Event::Key { code: Enter, .. }) => {},
}

This could be done if we declared Key inside the Event struct, but unfortunately it's used in console as well (Which is the recommended method of getting events, console or input?).

[tomassedovic]

Yeah, that is a bit silly. I wonder if the upcoming struct & enum unification could help here (haven't followed it too thoroughly yet).

If you're just getting keyboard input, console is the place to go, if you want mouse or both, then input. At least that's how I understand libtcod. It being a roguelike toolkit, mouse is sidelined a bit... Especially since it's more painful to match generic events instead of just the key ones.

[zsparal]

Well, other than that it seems good to me. Once it's merged I'll go and see if returning a dedicated Event type would make matching a bit easier (instead of the current tuple of (EventFlags, Event).