class Form
  extend Validatable
end

↓

class Form
  class Unvalidated
    sig { returns(Validated) }
    def validate
    end
  end

  class Validated
  end
end

wrap any errors and provides utility methods to create statically typed errors easily like anyhow.
add rake tasks to keep those types up to date.

like syntax suger, add a dsl to write algebraic data types fast and easily.

to do something like this

    class Row
      column :email,
        String,
        display: 'メールアドレス',
        deserialize: ->(value) { parse(value) }, # returns Result
        serialize: ->(value) { value.strip } # returns Result
    end

I want a dev server or something that watches files, runs RSpec continuously, and serves coverage and documents.

• refine
• deprecate if needed

• and_err(err)
  Returns self if self is Err. otherwise returns e.
• or_ok(ok)
  Returns self if self is Ok. otherwise returns ok.

https://github.com/kazzix14/mangrove/blob/8332508c338011b2c47d010f4970edc8a2fa9cb1/spec/mangrove/result/ok_spec.rb#L105C1-L105C1

Like this one.

class MyEnum
  extend Mangrove::Enum

  variants do
    variant V0, [MyModel, Integer]
  end
end

The reason is Hash#to_s and Array#to_s is an alias of #inspect, which calls its children's SomeClass#inspect.