Class: Dry::Effects::Effects::State

Inherits:
Module
  • Object
show all
Defined in:
lib/dry/effects/effects/state.rb

Direct Known Subclasses

Reader

Defined Under Namespace

Classes: State

Instance Method Summary collapse

Constructor Details

#initialize(scope, default: Undefined, writer: true, as: scope) ⇒ State

Returns a new instance of State.



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# File 'lib/dry/effects/effects/state.rb', line 13

def initialize(scope, default: Undefined, writer: true, as: scope)
  super()

  read = State.new(type: :state, name: :read, scope: scope)
  write = State.new(type: :state, name: :write, scope: scope)

  module_eval do
    if Undefined.equal?(default)
      define_method(as) do |&block|
        if block
          Undefined.default(::Dry::Effects.yield(read) { Undefined }, &block)
        else
          value = ::Dry::Effects.yield(read) { raise Errors::MissingStateError, read }

          Undefined.default(value) { raise Errors::UndefinedStateError, read }
        end
      end
    else
      define_method(as) do |&block|
        if block
          Undefined.default(::Dry::Effects.yield(read) { Undefined }, &block)
        else
          Undefined.default(::Dry::Effects.yield(read) { Undefined }, default)
        end
      end
    end

    if writer
      define_method(:"#{as}=") do |value|
        ::Dry::Effects.yield(write.(value: value))
      end
    end
  end
end