Add refactor to write RBS

examples/ex2_input.rb

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+# example from https://blog.kiprosh.com/type-checking-in-ruby-3-using-rbs/
+# basic_math.rb
+
+class BasicMath
+  def initialize(num1, num2)
+    @num1 = num1
+    @num2 = num2
+  end
+
+  def first_less_than_second?
+    @num1 < @num2
+  end
+
+  def add
+    @num1 + @num2
+  end
+end

examples/ex2_write_rbs.yml

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+refactor: ruby/write_rbs
+input_file_paths:
+  - examples/ex2_input.rb
+# We need to add context here as our class doesnt actually give any context.
+context_text: "Assume that the inputs can be any numeric type."
+# By default this refactor writes to `sig/...` but here we just put the result in `examples/...`
+output_file_path: examples/outputs/ex2_input.rbs

lib/ai_refactor/refactors/ruby/write_rbs.md

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+You are an expert Ruby senior software developer.
+
+You will be writing the type signatures for the Ruby code below, in RBS format.
+
+RBS is a language to describe the structure of Ruby programs. You can write down the definition of a class or module: methods defined in the class, instance variables and their types, and inheritance/mix-in relations. It also allows declaring constants and global variables.
+
+The following is a small example of RBS for a chat app.
+
+```
+module ChatApp
+  VERSION: String
+
+  class User
+    attr_reader login: String
+    attr_reader email: String
+
+    def initialize: (login: String, email: String) -> void
+  end
+
+  class Bot
+    attr_reader name: String
+    attr_reader email: String
+    attr_reader owner: User
+
+    def initialize: (name: String, owner: User) -> void
+  end
+
+  class Message
+    attr_reader id: String
+    attr_reader string: String
+    attr_reader from: User | Bot                     # `|` means union types: `#from` can be `User` or `Bot`
+    attr_reader reply_to: Message?                   # `?` means optional type: `#reply_to` can be `nil`
+
+    def initialize: (from: User | Bot, string: String) -> void
+
+    def reply: (from: User | Bot, string: String) -> Message
+  end
+
+  class Channel
+    attr_reader name: String
+    attr_reader messages: Array[Message]
+    attr_reader users: Array[User]
+    attr_reader bots: Array[Bot]
+
+    def initialize: (name: String) -> void
+
+    def each_member: () { (User | Bot) -> void } -> void  # `{` and `}` means block.
+                   | () -> Enumerator[User | Bot, void]   # Method can be overloaded.
+  end
+end
+```
+
+Do not include comments in your RBS code.
+
+__{{context}}__
+
+__{{prompt_header}}__
+
+The input file is: __{{input_file_path}}__
+The output file path is: __{{output_file_path}}__
+
+__{{prompt_footer}}__

lib/ai_refactor/refactors/ruby/write_rbs.rb

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+# frozen_string_literal: true
+
+module AIRefactor
+  module Refactors
+    module Ruby
+      class WriteRbs < BaseRefactor
+        def run
+          logger.verbose "Write some RBS for #{input_file}..."
+          logger.verbose "Write output to #{output_file_path}..." if output_file_path
+
+          begin
+            output_content = process!(strip_ticks: true)
+          rescue => e
+            logger.error "Failed to process #{input_file}: #{e.message}"
+            return false
+          end
+
+          return false unless output_content
+
+          output_file_path ? true : output_content
+        end
+
+        def self.description
+          "User supplied prompt to write RBS for some Ruby"
+        end
+
+        def default_output_path
+          File.join("sig", input_file.gsub(/\.rb$/, ".rbs"))
+        end
+      end
+    end
+  end
+end