AttrWithClass

Ruby metaprogramming helpers that create type-safe attribute accessors

class SomeClass
  attr_accessor_with_class String, :some_string, :some_other_string
end

Installation

Add this line to your application's Gemfile:

gem 'attr_with_class'

And then execute:

$ bundle

Or install it yourself as:

$ gem install attr_with_class

Usage

class Person
  attr_accessor_with_class String, :name, :email

  attr_accessor_with_non_negative_integer Integer, :age

  attr_accessor_with_handler :favourite_ice_cream do |val|
    raise ArgumentError, "must be a valid flavour" unless ["vanilla", "chocolate"].include(val)
    val
  end
end

person = Person.new

person.name = "Alice"    # works
person.name = 123        # raises ArgumentError: 123 is not a String

person.age = 30          # works
person.age = -1          # raises ArgumentError: -1 is not a non-negative integer

person.favourite_ice_cream = "vanilla"
person.favourite_ice_cream = "pistachio" #raises ArgumentError: must be a valid flavour

Available Methods

attr_writer / attr_accessor _with_handler(*attrs, &block)

writer or accessor with custom validation/transformation block

attr_writer / attr_accessor _with_class(klass, *attrs)

writer or accessor that enforces class (or subclass)

attr_writer / attr_accessor _with_non_negative_integer(*attrs)

writer or accessor that enforces non-negative integers

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/bpenn9/attr_with_class.