[wip]Introduce rbs and add a type definition file for processing.rb first

[ericgpks]

No description provided.

[kojix2]

The name "Processing" was chosen somewhat casually with the Japanese word "処理" in mind, so feel free to suggest a better name if you have one. Sometimes, people mistake it for the Processing programming language.

[Copilot]

Pull request overview

This PR introduces initial RBS/Steep support for the Ruby codebase, starting with a signature for YouPlot::Backends::Processing.count_values.

Changes:

• Adds a Steepfile targeting lib with signatures under sig.
• Adds development dependencies for Steep and TypeProf on Ruby 3.0+.
• Adds an initial RBS definition for processing.rb.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
Steepfile	Adds a Steep target for checking lib against sig.
Gemfile	Adds Steep and TypeProf as development dependencies for Ruby 3.0+.
sig/youplot/backends/processing.rbs	Adds the initial RBS signature for the processing backend.

Comments suppressed due to low confidence (2)

sig/youplot/backends/processing.rbs:4

• The keyword types are literal-only here: ?tally: true disallows the existing tally: false call path, and ?reverse: false disallows the count command when --reverse passes true. These should be typed as booleans so Steep accepts both supported values.

      def count_values: ([], ?tally: true, ?reverse: false) -> Array[Array[untyped]]

sig/youplot/backends/processing.rbs:4

• This declares only an instance method on the module, but processing.rb uses module_function and the code calls YouPlot::Backends::Processing.count_values as a module singleton method. As written, the public call sites will not be covered by this signature.

      def count_values: ([], ?tally: true, ?reverse: false) -> Array[Array[untyped]]

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[kojix2]

Sorry for the late reply.

I would like to take this opportunity to learn a little about the ecosystem of external type definition files in Ruby, and what they mean in practice.

[kojix2]

Note:
I like Crystal, but I am not a strong believer in static typing.
I do not think typed code is always better than untyped code.
I just want to learn more through OSS work. Thank you.