Initial template literal lexer implementation

[croraf]

Starting to implement. Would like this to be merged now.

[croraf]

I also slipped in a move of self.next() into the match of the lexer itself.

In the first commit there is one line related to this:

ch if ch.is_alphabetic() || ch == '$' || ch == '_' => {

And the rest is in the second commit.

[croraf]

So this PR consists of two separate things. 1 is start of implementation of template literal, 2 is putting the self.next inside the match construct.

[jasonwilliams]

@croraf this would need some tests to show it working

[croraf]

I added 2 tests.

[jasonwilliams]

@croraf thanks, I’ll have a play with this

[croraf]

I will soon close this and split in 2 PRs.

[Razican]

I think the template lexing has been implemented in #455, right? Can we close this?

[croraf]

I wanted to do a minor refactor of lexer that is present as part of this PR but otherwise the PR is obsolete.

[croraf]

From this obsolete PR the only thing that remains is the small refactor of the match construct in main lexer loop. Instead of getting the next character before match I put it as a part of the match. Check "boa/src/syntax/lexer/mod.rs" in the changed files.

If you like it I will make a separate PR with it?

[Razican]

If you like it I will make a separate PR with it?

All that will soon change with #432. I think it's best to invest on that by doing PRs to that branch :)

[croraf]

@Razican I thought so. I will close this then.