array operators don't match spec

[ansis]

The implementation uses ||, &&, !, $or, $and, $nor while the spec uses |, &, ^, !

mapbox-gl-js/js/style/bucketfilter.js

Lines 24 to 28 in 8ff29b8

	var arrayOperators = {
	'||': or, '$or': or,
	'&&': and, '$and': and,
	'!': nor, '$nor': nor
	};

https://github.com/mapbox/mapbox-gl-style-spec/blob/d1fc14b44e68dc30fc9990bc1329107265cdd8f8/reference/v4.json#L426-L438

Which do we want?

@mourner @nickidlugash @edenh

[kkaefer]

native uses the spec operators: https://github.com/mapbox/mapbox-gl-native/blob/master/src/style/style_parser.cpp#L748-L760

[mourner]

Yeah, but we need to choose one. I also remember that we settled on ||/&& notation in one of the older filter discussion...

[jfirebaugh]

+1 for || & &&

[mourner]

Should we also keep the aliases ($and etc.)? They can make the style more readable.

[mourner]

It also looks like there's a difference to how operators apply to object vs array. In native, you can use both with any operator, the only difference being that object is AND by default and array is OR, which gets overriden by parent. In JS, you can only use and, or and nor with an array, and only use not with an object.

Seems like the native way is more convenient, so we can adopt it in JS, while renaming operator names (and adding aliases) in the spec.

[mourner]

On the other hand, there's no easy way to do NOT in native: yo have to use NOR in combination with AND which is pretty bulky.

[jfirebaugh]

Fixed with v6 filters.