kotlin: add basic regex parser

[dolik-rce]

Hello,

I'm a Kotlin programmer using Geany as my IDE and for a long time I've been missing support this wonderful language. I've got some spare free time around Christmas, so I've decided to try and add a simple regex parser for Kotlin. Also, others have requested support for Kotlin in #1566.

I have tried to read all the docs related to contributions, but it is quite extensive and I'm pretty sure that I must have missed some parts 🙂 Please let me know if there is something missing from the code, before it could be merged. I'll try to fix any imperfections ASAP.

[coveralls]

Coverage increased (+0.01%) to 87.212% when pulling aa1f1cd on dolik-rce:kotlin-parser into 165f7e3 on universal-ctags:master.

[masatake]

Could you add a URL for the language reference page of Kotlin?

[dolik-rce]

Added

[masatake]

Thank you for your contribution. Knowing some writing a parser with mtable-regex that I designed is my greatest pleasure.

Though I don't know Kotlin, the parser looks good. I'm always surprised that people write a parser by reading the documents written in my bad English:-) I will take more time to verify the consistency of the transition between tables.

Have you tried to fill scope fields?
If you have not done yet I would like you to read scope= related description in https://docs.ctags.io/en/latest/man/ctags-optlib.7.html#flags-for-regex-lang-option . If you fill the scope fields, Geany may be able to build a "tree" from the information.

Here is an example illustrating the concept of scope.
input.c:

struct point {
   int x;
   int y;
};

tags output:

$ u-ctags --fields=+Z -o - input.c
point	input.c	/^struct point {$/;"	s	file:
x	input.c	/^	int x;$/;"	m	scope:struct:point	typeref:typename:int	file:
y	input.c	/^	int y;$/;"	m	scope:struct:point	typeref:typename:int	file:

Could you recommend to me a larger open-source software project using Kotlin?
I would like to register it to our codebase (https://github.com/universal-ctags/codebase).

[dolik-rce]

Thank you for your quick replies @masatake.

English is not my first language either, but your documentation is great. It was quite easy to follow, considering how extensive the ctags options are.

I think, without the mtable-regex it would be almost impossible to write the parser for Kotlin. Switching contexts makes it much easier.

Regarding the scopes: I've been looking into it, but it's not going to be easy. Kotlin allows nested definitions (for both classes and functions) and often uses anonymous constructs (lot of lambdas, but also anonymous classes) so tracking the scope will be tricky. Therefore I chose to submit this simpler version first and maybe try to add scope later.

For the codebase, I can recommend you for eaxmple dokka, which is a documentation engine for Kotlin. It's not really large, but I can't think of any better example right now... Most of the Kotlin usage is still for Android apps, which I don't know much. I'm a back-end developer, using Kotlin for proprietary servers.

[dolik-rce]

I see the code is failing on OS X and cygwin. Is there something that needs to be done differently for those platforms?

[masatake]

I'll inspect the reason of the failure.

[masatake]

See 8992b8c (#2770).
It seems that you cannot use \s. Please replace it with [[:space:]] or [ \t].

[masatake]

Could you add "Kotlin" to https://github.com/universal-ctags/ctags/blob/master/docs/news.rst ?

[codecov]

Codecov Report

Merging #2769 (aa1f1cd) into master (165f7e3) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2769      +/-   ##
==========================================
+ Coverage   87.11%   87.13%   +0.01%     
==========================================
  Files         192      193       +1     
  Lines       40892    40941      +49     
==========================================
+ Hits        35625    35674      +49     
  Misses       5267     5267              

Impacted Files	Coverage Δ
optlib/kotlin.c	100.00% <100.00%> (ø)

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[masatake]

Thank you.