Add SAS lexer and accompanying files

[tomsutch]

Add lexer for SAS.

It's a bit of an odd language with lots of keywords, most of them specific to individual procedures, so I hope I have gone about this in an appropriate way. I haven't attempted to implement all of the procedure-specific stuff by any means.

Happy to change in response to feedback :-)

[pyrmont]

Forgive me, @tomsutch. It might take a bit of time to get through this lexer—there sure are a lot of keywords!

[pyrmont]

@tomsutch I do wonder if there's some shortcut to identifying keywords (such as by position) as it seems like there's a lot of matching being done to produce relatively few distinct tokens.

[tomsutch]

@pyrmont Thanks for your feedback. I'll take a look at your comments in detail over the coming days.

[ashmaroli]

You'll need to resolve all offenses reported by RuboCop:
https://travis-ci.org/rouge-ruby/rouge/jobs/554691134

[ashmaroli]

Some more corrections to regexps in the lexer..

[pyrmont]

@tomsutch Any luck fixing the outstanding items in this PR?

[ashmaroli]

@tomsutch I hate to inform you but looks like Travis CI failed with some linting errors. Please fix.
Thanks.

[pyrmont]

@tomsutch Before pushing, it's a good idea to run the following:

rake && bundle exec rubucop bin lib spec tasks

If that runs without error then your code should pass Travis as well.

[tomsutch]

You'll need to resolve all offenses reported by RuboCop:
https://travis-ci.org/rouge-ruby/rouge/jobs/554691134

Thanks - the latest build is https://travis-ci.org/rouge-ruby/rouge/jobs/559860704
It consists entirely of 'offenses' like this

Lint/AmbiguousRegexpLiteral: Ambiguous regexp literal. Parenthesize the method arguments if it's surely a regexp literal, or add a whitespace to the right of the / if it should be a division.

There's one offense for every instance of rule /.../

I'm certainly happy to do what's needed to fix this, but I don't understand why these are happening when other lexers contain similar rules in similar formats and don't get picked up by Rubocop. Do you know why this might be?

[ashmaroli]

The offense is simply rule /.../. Other lexers may have it like rule %r/.../ or rule(/.../)

[pyrmont]

@tomsutch The explanation given by RuboCop is brief but, essentially, RuboCop flags the use of literal regular expressions of the form /.../ in method arguments as ambiguous because it's not clear whether the initial / represents the beginning of a regular expression or a method called /.

Other lexers avoid this warning by either using a sigil to mark the beginning of the regex (%r so that it becomes %r/.../) or wrapping the parameters inside parentheses.

[tomsutch]

@tomsutch The explanation given by RuboCop is brief but, essentially, RuboCop flags the use of literal regular expressions of the form /.../ in method arguments as ambiguous because it's not clear whether the initial / represents the beginning of a regular expression or a method called /.

Other lexers avoid this warning by either using a sigil to mark the beginning of the regex (%r so that it becomes %r/.../) or wrapping the parameters inside parentheses.

Ah, thanks. Now I see that the the other lexers I was referring to when putting this together have also been changed accordingly via #1180. I'll fix this now.

[tomsutch]

I think I've now addressed all the feedback, if you're happy with my response to your request @pyrmont?
Thanks everyone for your patience!

[pyrmont]

@tomsutch Thanks for the contribution to Rouge :) Another language that's highlighted! 🎉