Add lexer for ReasonML

[sazarkin]

Hi, I've added support for ReasonML https://reasonml.github.io/

[pyrmont]

Awesome! A ReasonML lexer! Had a couple of questions :)

[pyrmont]

@jneen Do you have an opinion on the way this has been structured? Rather than using the OCaml lexer as the superclass and simply overriding the bits that don't make sense, @sazarkin has separated the shared elements into a common class that both lexers inherit from (similar to how Rouge::Lexers::TypescriptCommon works).

[jneen]

seems ok to me

[sazarkin]

Thanks for a great feedback, I'll try to improve this PR

[ashmaroli]

@sazarkin IMO, the entire :comment state can be removed and just have the following at ln#27

rule %r(/\*.*?\*/)m, Comment

[jneen]

@sazarkin IMO, the entire :comment state can be removed and just have the following at ln#27

rule %r(/\*.*?\*/)m, Comment

@ashmaroli we actually encourage breaking lexers down into further states, as it makes it possible to embed or escape within those states.

(edit): also... it can't. These comments are nestable (see the invocation of push).

[jneen]

It could stand to be written a little more neatly though, with less backslashes:

rule %r|[^/*)]+|, Comment
rule %r|[/][*]|, Comment, :push
rule %r|[*][/]|, Comment, :pop!
rule %r|[*/]|, Comment

[pyrmont]

@sazarkin See also @jneen's suggestion above about how to express the comment rules.

[sazarkin]

Updated the comment part

[pyrmont]

@sazarkin Thanks! Great to have a lexer for ReasonML as part of Rouge 🎉