Sinclair

This gem helps the creation of complex concern with class methods

Getting started

1. Installation

• Install it

  gem install sinclair

- Or add Sinclairn to your `Gemfile` and `bundle install`:

```ruby
gem 'sinclair'
```

```bash
bundle install sinclair
```

2. Using it: The concern builder can actully be used in two ways, as an stand alone object capable of adding methods to your class or by extending it for more complex logics

• Stand Alone usage:

  class Clazz
  end

  builder = Sinclair.new(Clazz)

  builder.add_method(:twenty, '10 + 10')
  builder.add_method(:eighty) { 4 * twenty }
  builder.build

  instance = Clazz.new

  puts "Twenty => #{instance.twenty}"
  puts "Eighty => #{instance.eighty}"

  Twenty => 20
  Eighty => 80

• Extending the builder

  class ValidationBuilder < Sinclair
    delegate :expected, to: :options_object

    def initialize(clazz, options={})
      super
    end

    def add_validation(field)
      add_method("#{field}_valid?", "#{field}.is_a?#{expected}")
    end

    def add_accessors(fields)
      clazz.send(:attr_accessor, *fields)
    end
  end

  module MyConcern
    extend ActiveSupport::Concern

    class_methods do
      def validate(*fields, expected_class)
        builder = ::ValidationBuilder.new(self, expected: expected_class)

        validatable_fields.concat(fields)
        builder.add_accessors(fields)

        fields.each do |field|
          builder.add_validation(field)
        end

        builder.build
      end

      def validatable_fields
        @validatable_fields ||= []
      end
    end

    def valid?
      self.class.validatable_fields.all? do |field|
        public_send("#{field}_valid?")
      end
    end
  end

  class MyClass
    include MyConcern
    validate :name, :surname, String
    validate :age, :legs, Integer

    def initialize(name: nil, surname: nil, age: nil, legs: nil)
      @name = name
      @surname = surname
      @age = age
      @legs = legs
    end
  end

  instance = MyClass.new

the instance will respond to the methods

name name= name_valid? surname surname= surname_valid? age age= age_valid? legs legs= legs_valid? valid?

```ruby
valid_object = MyClass.new(
  name: :name,
  surname: 'surname',
  age: 20,
  legs: 2
)
valid_object.valid?
```

returns

```
true
```

```ruby
invalid_object = MyClass.new(
  name: 'name',
  surname: 'surname',
  age: 20,
  legs: 2
)
invalid_object.valid?
```

returns

```
false
```