Move Starlark to separate language

[arturdryomov]

Starlark is a scripting language inspired by Python.

• At this point GitHub recognizes and highlights Starlark files as Python files which is not exactly true. The Python code is not compatible with Starlark interpreters in full extent.
• At the same time, it is a bit weird to see repos with Python code when in fact all the code is Starlark.

Starlark is mostly a Bazel build system child. But it gains a bit of traction. For example, the Buck build system adopts it as well. Interestingly Drone CI supports Starlark as a configuration language.

GitHub stats:

• .bzl files (118K hits);
• .bazel files (413K hits);
• .star files (20K hits);
• .starlark files (41 hits);

What this change does:

• defines a new Starlark language based on Python semantics;
• moves everything Starlark, Bazel (BUILD, WORKSPACE) and Buck (BUCK) related from Python to Starlark;
• moves samples and adds a new one with the .starlark extension;
• since Starlark is a part of the Bazel family I’ve defined the color as a Bazel green one (preview).

CC @jin, @artem-zinnatullin

[artem-zinnatullin]

Noice

[jin]

Copybara uses *.sky as well.

The Go Starlark interpreter examples uses *.star.

[arturdryomov]

I think .sky should be abandoned since Skylark is Starlark at this point. Gonna add .star since there are 20K hits and it might be a widespread extension in the future. Thanks!

[Alhadis]

You'll need to remove .starlark because it falls short of our usage requirements (only 41 files at the time of writing). Otherwise, this looks file to me.

[jin]

Hmm, typo?

[Alhadis]

@jin Not a typo. The list is auto-generated from whatever grammars are assigned to a language, which in this case happens to be Python.

[Alhadis]

You'll need to remove .starlark because it falls short of our usage requirements (only 41 files at the time of writing). Otherwise, this looks file to me.

[arturdryomov]

@Alhadis, thanks for the review! What are next steps? I guess @lildude does the merging (taking merged PRs into account).

[Alhadis]

Yup, just have to wait for a GitHub staff member to give their 👍 of approval before we can merge.

[pchaigno]

Thanks for your contribution @arturdryomov!

I've left a couple comments inline. I'm 👍 for the separation of Starlark and Python, but have some concerns regarding the two new file extensions (see below).

/cc @Dominator008 who added the .bzl extension to Python in #2846.

[jin]

fyi @laurentlb @alandonovan

[arturdryomov]

@pchaigno, do we need to make some changes to merge this? I hope I haven’t missed something 😰

[arturdryomov]

@pchaigno, sorry for pinging you again. Is there anything else needs to be changed? Just attempting to not abandon this PR when it slips away from the Recent Activity section on GitHub 😉

[Alhadis]

@arturdryomov We need to wait for a GitHub staff member to give a final 👍 of approval before we can merge. 😉 It's a matter of policy, because Linguist is a production dependency of the site.

[arturdryomov]

@Alhadis, ah, thanks! I thought @pchaigno is from the GitHub team for some reason 🤔 I guess I saw some merges from you guys.

[arturdryomov]

Huzza! Thanks @lildude!

[c4milo]

I see you mentioned .star as one of the extensions in your PR description. Any reason why it was left out?

[pchaigno]

@c4milo Please see #4759 (comment).