DryStructRbs

A Ruby gem that automatically generates RBS type definitions for your dry-struct classes.

Installation

Add to your Gemfile in the development group:

group :development do
  gem 'dry_struct_rbs',
      git: 'https://github.com/seek-oss/dry_struct_rbs',
      branch: 'master'
end

Then execute:

bundle install

Usage

Generate RBS files for your application with a single command:

bundle exec dry_struct_rbs app

Options

Option	Description
-w	Write generated files to disk (without this flag, output is only displayed)
-f	Force overwrite existing RBS files
-n NAMESPACE	Set your dry-types namespace (default: Types)
-i PATH	Ignore directory prefix when generating output paths

Examples

Basic usage with file writing:

bundle exec dry_struct_rbs app -w

Generate files with a custom namespace and force overwrite:

bundle exec dry_struct_rbs app -w -f -n MyApp::Types

Generate files while stripping a directory prefix from output paths:

bundle exec dry_struct_rbs app/models/user.rb -w -i app/models

This will transform input paths like app/models/user.rb to sig/user.rbs instead of sig/app/models/user.rbs.

Transformation Example

This gem automatically transforms your dry-struct Ruby classes into proper RBS type definitions. Here's an example:

Original Ruby class:

module Order
  class Product < Dry::Struct
    attribute :id, Types::Integer
    attribute :name, Types::String
    attribute :price, Types::Float
    attribute :tags, Types::Array.of(Types::String)
    attribute :metadata, Types::Hash.of(Types::String, Types::Any)
    attribute :available, Types::Bool
    attribute :description, Types::String.optional
    attribute? :vendor_code, Types::Integer
  end
end

Generated RBS type definition:

module Order
  class Product < Dry::Struct
    attr_reader id: Integer
    
    attr_reader name: String
    
    attr_reader price: Float
    
    attr_reader tags: Array[String]
    
    attr_reader metadata: Hash[String, untyped]
    
    attr_reader available: bool
    
    attr_reader description: String?
    
    attr_reader vendor_code: Integer?
  end
end

The gem handles various complex dry-types constructs and automatically maps them to their appropriate RBS equivalents.

Mermaid Diagram (click to expand)

flowchart TD
    subgraph Step1["Traverse Ruby AST"]
        Order1[Order]
        Product1[Product]
        id1[id: Types::Integer]
        name1[name: Types::String]
        price1[price: Types::Float]
        Order1 --> Product1
        Product1 --> id1
        Product1 --> name1
        Product1 --> price1
    end

    subgraph Step2["Convert DRY Types to RBS Types"]
        idconv[Types::Integer → Integer]
        nameconv[Types::String → String]
        priceconv[Types::Float → Float]
    end

    subgraph Step3["Build RBS AST"]
        id2[id: Integer]
        name2[name: String]
        price2[price: Float]
        Product2[Product]
        Order2[Order]
        id2 --> Product2
        name2 --> Product2
        price2 --> Product2
        Product2 --> Order2
    end

    Step1 --> Step2
    Step2 --> Step3

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Contributing

We welcome contributions from the community! Please check our contribution guidelines for more details on how to get involved.

License

The gem is available as open source under the terms of the MIT License.