Class: Yarrow::Schema::Value

Inherits:
Object
  • Object
show all
Defined in:
lib/yarrow/schema.rb

Overview

Value object (with comparison by value equality). This just chucks back a Ruby struct but wraps the constructor with method advice that handles validation (and eventually type coercion if !yagni).

Class Method Summary collapse

Class Method Details

.factory(*slots, **fields, &block) ⇒ Object 



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# File 'lib/yarrow/schema.rb', line 37

def self.factory(*slots, **fields, &block)
  if slots.empty? && fields.empty?
    raise ArgumentError.new("missing attribute definition")
  end

  slots_spec, fields_spec = if fields.any?
    raise ArgumentError.new("cannot use slots when field map is supplied") if slots.any?
    [fields.keys, fields]
  else
    [slots, Hash[slots.map { |s| [s, Type::Any]}]]
  end

  validator = Validator.new(fields_spec)

  struct = Struct.new(*slots_spec, keyword_init: true, &block)

  struct.define_method :initialize do |*args, **kwargs|
    attr_values = if args.any?
      raise ArgumentError.new("cannot mix slots and kwargs") if kwargs.any?
      Hash[slots.zip(args)]
    else
      kwargs
    end

    validator.check(attr_values)
    # TODO: type coercion or mapping decision goes here
    super(**attr_values)

    freeze
  end

  struct
end

.new(*slots, **fields, &block) ⇒ Object 



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# File 'lib/yarrow/schema.rb', line 33

def self.new(*slots, **fields, &block)
  factory(*slots, **fields, &block)
end