Coercion is not run without validation about validations

[lasseebert]

I should add that in this example, I don't care about validations, only coercion.

[jodosha]

@lasseebert I apologize for taking so long to reply.

Coercion can't be performed at the initialization time because of it can potentially raise TypeError.
Because params are instantiated before your implementation of #call is invoked, in case of failed coercion, your app will return server side error, without you are even able to control the flow.

Would you please explore the lazy coercion alternative? Thanks!

[lasseebert]

If coercion is treated as some kind of special validation (not run on valid?) it could instead be run (and memoized) the first time that attribute is accessed.

Something like

# lib/lotus/validations.rb
module Lotus
  module Validations
    # ...
    module ClassMethods
      def attribute(name, options = {})
        attributes[name.to_sym] = validate_options!(name, options)

        class_eval %{
          def #{ name }
            @coerced[:#{ name }]
          end
        }
      end
      # ...
    end

    def initialize(attributes)
      @attributes = attributes
      @coerced = Hash.new { |hash, key| hash[key] = coerce(attributes[key]) if attributes[key] }
    end
    # ...
  end
end

I'm not sure that this is the way to go, but for me it was a gotcha that coercion is treated as a validation. Specially in the case when coercion is the only validation I'm using, then it does not make sense to call valid? before using the attributes.

I guess that when using lotus-validations on it's own, it makes more sense to that you have to call some method before anything happens. My case was from a lotus application.

[lasseebert]

Very nice, thank you very much! :)

[jodosha]

@lasseebert 🎩 expect a new release on sunday.