Update for Swift 4.2

[mattt]

This PR improves support for Swift 4.2 with the following changes:

• Add support for keywords beginning with # (e.g. #available)
• Fix syntax for octal integer literals (e.g. 0o744)
• Add support for multi-line string literals, which are delimited by three quotation marks (""")

[mwaterfall]

Would love this to be merged! 🙏🏻 @dblessing @jneen

[pyrmont]

@mattt Sorry it's taken so long to get around to this one :( Would you be able to add some of these to the visual sample? Don't need to list all the keywords, just a couple of additions to show this working properly.

[mattt]

@pyrmont Sure thing! See 08b9917

[pyrmont]

This generally looks fine but I noticed that the p in the hexadecimal floating point isn't being picked up as a number. Shouldn't it be?

[mattt]

@pyrmont That wasn't in the original scope of this patch, but I just implemented it in
bbec13e.

Tangentially: What's your process for checking / verifying the result of the visual sample?

[pyrmont]

@mattt wrote:

Tangentially: What's your process for checking / verifying the result of the visual sample?

There probably should be a more mechanical (and, hence, reliable) process but honestly, at the moment, I just look at it with the naked eye and try to find mistakes. That's basically how I identified the problems with the floating point/hex regular expressions.

[mattt]

There probably should be a more mechanical (and, hence, reliable) process but honestly, at the moment, I just look at it with the naked eye and try to find mistakes. That's basically how I identified the problems with the floating point/hex regular expressions.

Oh, wow. I was expecting there to be some command that you could run to quickly generate an HTML preview of the current rules applied to the visual sample. Does that not exist? And if not, is this something you'd consider in a PR?

[pyrmont]

@mattt Oh, wait. I may have misunderstood your original question. You realise if you run rackup from the project root, it'll spin up a quick server at http://localhost:8000/ that will display the visual samples as webpages, right?

[pyrmont]

@mattt I hope you don't mind but I took the liberty of pushing a commit to your branch with the necessary fix. Hopefully that means we can get this merged :)

I also realised that the link I gave you before was wrong. I manually set my port to be 8000 but by default running bundle exec rackup will launch the server at http://localhost:9292/.

Hope that helps for any future PRs!

[pyrmont]

@mattt This has been successful merged. Thanks for making Rouge a better library :)

[mattt]

@pyrmont Thanks for your help and guidance through the process. Looking forward to sending more PRs in the future.