Module: Stannum::Struct

Includes:
Entities::Attributes, Entities::Constraints, Entities::Properties
Defined in:
lib/stannum/struct.rb

Overview

Abstract class for defining objects with structured attributes.

Examples:

Defining Attributes

class Widget
  include Stannum::Struct

  attribute :name,        String
  attribute :description, String,  optional: true
  attribute :quantity,    Integer, default:  0
end

widget = Widget.new(name: 'Self-sealing Stem Bolt')
widget.name        #=> 'Self-sealing Stem Bolt'
widget.description #=> nil
widget.quantity    #=> 0
widget.attributes  #=>
# {
#   name:        'Self-sealing Stem Bolt',
#   description: nil,
#   quantity:    0
# }

Setting Attributes

widget.description = 'A stem bolt, but self sealing.'
widget.attributes #=>
# {
#   name:        'Self-sealing Stem Bolt',
#   description: 'A stem bolt, but self sealing.',
#   quantity:    0
# }

widget.assign_attributes(quantity: 50)
widget.attributes #=>
# {
#   name:        'Self-sealing Stem Bolt',
#   description: 'A stem bolt, but self sealing.',
#   quantity:    50
# }

widget.attributes = (name: 'Inverse Chronoton Emitter')
# {
#   name:        'Inverse Chronoton Emitter',
#   description: nil,
#   quantity:    0
# }

Defining Attribute Constraints

Widget::Contract.matches?(quantity: -5)                    #=> false
Widget::Contract.matches?(name: 'Capacitor', quantity: -5) #=> true

class Widget
  constraint(:quantity) { |qty| qty >= 0 }
end

Widget::Contract.matches?(name: 'Capacitor', quantity: -5) #=> false
Widget::Contract.matches?(name: 'Capacitor', quantity: 10) #=> true

Defining Struct Constraints

Widget::Contract.matches?(name: 'Diode') #=> true

class Widget
  constraint { |struct| struct.description&.include?(struct.name) }
end

Widget::Contract.matches?(name: 'Diode') #=> false
Widget::Contract.matches?(
  name:        'Diode',
  description: 'A low budget Diode',
) #=> true

Instance Method Summary collapse

Methods included from Entities::Constraints

apply

Methods included from Entities::Attributes

apply, #assign_attributes, #attributes, #attributes=, #properties

Methods included from Entities::Properties

#==, #[], #[]=, #assign_properties, #inspect, #properties, #properties=, #to_h

Instance Method Details

#initialize(attributes = {}) ⇒ Object

Initializes the struct with the given attributes.

For each key in the attributes hash, the corresponding writer method will be called with the attribute value. If the hash does not include the key for an attribute, or if the value is nil, the attribute will be set to its default value.

If the attributes hash includes any keys that do not correspond to an attribute, the struct will raise an error.

Parameters:

  • attributes (Hash) (defaults to: {}) —

    The initial attributes for the struct.

Raises:

  • ArgumentError if given an invalid attributes hash.

See Also:



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# File 'lib/stannum/struct.rb', line 97

def initialize(attributes = {})
  unless attributes.is_a?(Hash)
    raise ArgumentError, 'attributes must be a Hash'
  end

  super(**attributes)

  SleepingKingStudios::Tools::CoreTools.deprecate(
    'Stannum::Struct',
    'use Stannum::Entity instead'
  )
end