Add support for ES6 Unicode code point escapes

[mathiasbynens]

Add support for ES6 Unicode code point escape sequences.

Diff without whitespace changes: https://github.com/jviereck/regjsparser/pull/11/files?w=1 (Some indentation was incorrect)

[jviereck]

Wondering: Should there be a option-flag to enable ES6 features for the parser? I am happy if this is a global flag, that can/needs to be set on the parser object directly and not for every call to the parse function, as I assume most people will use the same mode (es5/es6) over all calls to parse.

Does that sounds reasonable to you?

[mathiasbynens]

Ideally it should just work. If you’re authoring in ES5, there won’t be any \u{xxxxxx}-style escape sequences anyway. If you’re authoring in ES6 there might be, but I don’t see why we’d need a flag to parse them. For opt-in Unicode regex features, we already have the u flag in the input anyway.

[jviereck]

SGTM.

[jviereck]

Thanks a lot Mathias. I need to take a closer look at this tomorrow and read up on the ES6 unicode points/gramma changes but I have the feeling you know what you're doing ;)

[termi]

Hi folks! First of all, thx for the great work!
But I have to ask you: What the status of this branch?
Recently I needed to the es6 RegExp parser and the only one a have found is the one that present in this branch. But, unfortunately it's incomplete. So I had to do my own version of this branch. The reason for this:

1. Lack of Unicode surrogate support. change1 and change2. I am not sure that I am did it in a right way, but it works for me. Example:

parse('[\uD83D\uDCA9-\uD83D\uDCAB]', 'u').terms[0].classRanges[0].min
Object {type: "escape", name: "codePoint", value: "1F4A9", from: 1, to: 3, raw: "uD83DuDCA9"}

As you can see I am combined first unicode code point with second surrogate value. But only for RegExp with 'u' flag.
2. Incorrect from value as well as 'raw' value for 'characterClassRange' change3. I am sure this is a bug.
3. Due #3 still not closed I had to add my own option change4

[jviereck]

@termi, thanks for your comment! Would you mind to make a new PR with the changes 1-4 you have mentioned such that I can pull them in? Would really be happy to have them in the core library :)

[termi]

@jviereck I'll do it in one of these days

[termi]

@jviereck #13

[termi]

I guess it should be

return createEscaped('codePoint', res[1], 4);

to calculate the correct values of 'from' and 'raw' like in #12