Add support for NaniScript

[elringus]

NaniScript is a scenario scripting language used by Naninovel visual novel extension for Unity: https://naninovel.com

[elringus]

Sorry for the ongoing commits; it's ready now.

[RunDevelopment]

Thank you for making this pull request @elringus!

There are a few things we have to do before we can merge this.

I think it's largely ok as is (I looked at your documentation page and the highlight looks really good) but there a few smaller things we have to do (mostly simplifying and optimizing the regexes).

Also, you don't have to do these alone. If it's ok with you, then I'll make a PR to your branch that will include some of my suggestions.

[elringus]

Thank you for the review! @vladdancer is actually the main contributor here, hopefully he'll be able to provide some feedback on the suggestions. A PR to the fork would be great, thanks!

[RunDevelopment]

Quick question: How does escaping in strings work? The doc gives this example:

"Saying \\"Stop the car\\" was a mistake."

But I guess that this isn't how it is supposed to be tokenized:

(Screenshot of the DOM of the website)

So how does it work? It's not mentioned anywhere and the double escaping seems weird to me.

[elringus]

That's a special case here. The value of if operators is treated as expression by default (to save the user from typing curly braces every time) and expressions are evaluated with their own parser after being parsed by the main one, hence the need for double escape: \\" is replaced with \" on the initial parse and then the expression evaluator receive a properly escaped quote.

[RunDevelopment]

I see. Since doing this correctly will be quite difficult, let's just leave it as is.

[vladdancer]

@RunDevelopment thank you for a such great review!
I fixed remain issues and a couple of small improvements, added PR in Elringus repo.

[RunDevelopment]

Thank you for the changes @vladdancer and @elringus!

I still have some minor nits but after those, it's ready to go.

[RunDevelopment]

Thank you for contributing @elringus and @vladdancer!

[elringus]

Thank you for the help and patience with us!

[vladdancer]

@RunDevelopment Thanks one more time for such great review, it gives me more details about regular expressions!