Add Selection API

[paulyoung]

This adds the Selection API as documented on MDN. Non-standard features such as modify are not included.

Support for this API seems very good according to Can I use.

I would appreciate as much feedback as possible on this, particularly on the introduction of the SELECTION effect, and around the effects used in general.

Some feedback on the approach used for type would also be great.

I think it also makes sense to add more on the Range data type. I'd like to do this in accordance with the documentation on MDN but I'm not sure what the appropriate effect should be.

Thanks in advance.

[garyb]

I think this looks great. Re: type_, we can probably drop the Partial via unsafePartial - I think I've done that elsewhere whenever we implement the enumeration of possible string values according to the spec.

[paulyoung]

I fixed the conflicts with master locally but now I'm getting this:

[1/1 ScopeConflict] bower_components/purescript-eff/src/Control/Monad/Eff.purs:36:1

  36  foreign import data Eff :: # Effect -> Type -> Type
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

  Conflicting definitions are in scope for kind Effect from the following modules:

    Control.Monad.Eff
    Prim

[paulyoung]

Travis is OK with this so not sure what's happening locally.

[garyb]

That's the error you get if you try and compile 0.11 libraries with 0.10 - maybe old compiler in node_module getting picked up if you installed the npm dependencies locally? :)

[paulyoung]

@garyb I just fixed the latest conflicts. Please let me know if you think anything else needs to change here.

[paulyoung]

@garyb would you mind taking another look at this please?

[garyb]

I think all of these latter functions should perhaps have the Selection argument first for "normal" PS argument ordering?

[garyb]

Wait, disregard that, I think it probably is the right way around now.

I'll let you comment on that either way and then will merge :)

[paulyoung]

Now you've got me wondering!

[garyb]

I think it's tricky with this one, as it's usually "the thing that is being operated on goes last" - but due to the nature of this API, the selection is acting on a thing - that's what tripped me up.

I'm fine with it either way, just let me know what you want to do, now I've sown the seeds of doubt 😆

[garyb]

I was a little apprehensive about adding this, since it is still experimental and the spec is just a working draft... but at least there is a spec! And it's decently supported as you point out.

Sorry I ignored it for ages!