Class: Philiprehberger::StructKit::Definition

Inherits:
Object
  • Object
show all
Defined in:
lib/philiprehberger/struct_kit/definition.rb

Instance Method Summary collapse

Constructor Details

#initialize(mutable: false) ⇒ Definition

Returns a new instance of Definition.



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# File 'lib/philiprehberger/struct_kit/definition.rb', line 8

def initialize(mutable: false)
  @fields = {}
  @validations = {}
  @mutable = mutable
end

Instance Method Details

#build ⇒ Object

rubocop:disable Metrics/AbcSize, Metrics/MethodLength



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# File 'lib/philiprehberger/struct_kit/definition.rb', line 28

def build # rubocop:disable Metrics/AbcSize, Metrics/MethodLength
  fields = @fields.dup
  mutable = @mutable

  # Attach validations to fields
  @validations.each do |name, rules|
    next unless fields[name]

    rules.each { |rule| fields[name].add_validation(rule) }
  end

  klass = Class.new do
    class << self
      attr_accessor :_fields, :_mutable
    end

    fields.each_key do |fname|
      attr_reader fname
    end

    define_method(:initialize) do |**kwargs|
      self.class._fields.each do |fname, f|
        value = if kwargs.key?(fname)
                  kwargs[fname]
                elsif f.has_default?
                  f.resolve_default
                else
                  raise ArgumentError, "missing keyword: #{fname}"
                end

        value = f.coerce_value(value)

        unless f.type_valid?(value)
          expected = f.type.is_a?(Array) ? f.type.map(&:name).join(' or ') : f.type.name
          raise TypeError, "#{fname} must be #{expected}, got #{value.class}"
        end

        # Run validations
        validation_errors = f.validate_value(value)
        raise ArgumentError, validation_errors.join(', ') unless validation_errors.empty?

        instance_variable_set(:"@#{fname}", value)
      end

      freeze unless self.class._mutable
    end

    if mutable
      fields.each_key do |fname|
        attr_writer fname
      end
    end

    define_method(:to_h) do
      self.class._fields.each_with_object({}) do |(fname, _), hash|
        hash[fname] = instance_variable_get(:"@#{fname}")
      end
    end

    define_method(:to_a) do
      self.class._fields.keys.map { |fname| instance_variable_get(:"@#{fname}") }
    end

    define_method(:to_json) do |*args|
      require 'json'
      to_h.to_json(*args)
    end

    define_method(:with) do |**changes|
      unknown = changes.keys - self.class._fields.keys
      raise ArgumentError, "unknown keyword: #{unknown.first}" unless unknown.empty?

      self.class.new(**to_h, **changes)
    end

    define_singleton_method(:from_h) do |hash|
      sym_hash = hash.transform_keys(&:to_sym)
      new(**sym_hash)
    end

    define_singleton_method(:field_names) do
      _fields.keys
    end

    define_method(:deconstruct_keys) do |keys|
      h = to_h
      keys ? h.slice(*keys) : h
    end

    define_method(:==) do |other|
      other.is_a?(self.class) && to_h == other.to_h
    end

    define_method(:hash) do
      to_h.hash
    end

    define_method(:inspect) do
      fields_str = to_h.map { |k, v| "#{k}: #{v.inspect}" }.join(', ')
      "#<#{self.class.name || 'StructKit'} #{fields_str}>"
    end

    alias_method :to_s, :inspect
  end

  klass._fields = fields
  klass._mutable = mutable
  klass
end

#field(name, type = nil, default: Field::UNSET, coerce: nil) ⇒ Object 



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# File 'lib/philiprehberger/struct_kit/definition.rb', line 14

def field(name, type = nil, default: Field::UNSET, coerce: nil)
  @fields[name] = Field.new(name, type, default: default, coerce: coerce)
end

#validate(field_name, range: nil, format: nil, presence: nil, &block) ⇒ Object 



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# File 'lib/philiprehberger/struct_kit/definition.rb', line 18

def validate(field_name, range: nil, format: nil, presence: nil, &block)
  @validations[field_name] ||= []
  rules = {}
  rules[:range] = range if range
  rules[:format] = format if format
  rules[:presence] = presence unless presence.nil?
  @validations[field_name] << rules unless rules.empty?
  @validations[field_name] << block if block
end