Class: Decider::Module

Inherits:
Module
  • Object
show all
Defined in:
lib/decider.rb

Defined Under Namespace

Classes: Decide, Evolve, Terminal

Constant Summary collapse

DECIDE_FALLBACK = 
proc { [nil, proc {}] }
EVOLVE_FALLBACK = 
proc { [nil, proc { state }] }

Instance Method Summary collapse

Constructor Details

#initialize(initial_state:, deciders:, evolutions:, terminal:) ⇒ Module

Returns a new instance of Module.



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# File 'lib/decider.rb', line 60

def initialize(initial_state:, deciders:, evolutions:, terminal:)
  case initial_state
  in Proc
    define_method(:initial_state) do
      initial_state.call
    end
  else
    define_method(:initial_state) do
      initial_state
    end
  end

  define_method(:decide) do |command, state|
    context = Decide.new(command: command, state: state, _events: [])

    deciders.find(DECIDE_FALLBACK) do |args, _|
      case args
      in [Proc => fn]
        context.instance_exec(&fn)
      in [ctype]
        command in ^ctype
      in [ctype, stype]
        [command, state] in [^ctype, ^stype]
      else
        false
      end
    end => [_, handler]

    context.instance_exec(&handler)
    context._events
  end

  define_method(:evolve) do |*args|
    if args.empty?
      ->(state, event) { evolve(state, event) }
    else
      context = Evolve.build(*args)

      evolutions.find(EVOLVE_FALLBACK) do |args, _|
        case args
        in [Proc => fn]
          context.instance_exec(&fn)
        in [etype]
          context_event = context.event
          context_event in ^etype
        in [stype, etype]
          context_state = context.state
          context_event = context.event
          [context_state, context_event] in [^stype, ^etype]
        else
          false
        end
      end => [_, handler]

      context.instance_exec(&handler)
    end
  end

  define_method(:terminal?) do |state|
    context = Terminal.new(state: state)

    context.instance_exec(&terminal)
  end

  define_method(:lmap_on_command) do |fn|
    Decider.lmap_on_command(fn, self)
  end

  define_method(:lmap_on_state) do |fn|
    Decider.lmap_on_state(fn, self)
  end

  define_method(:map) do |fn|
    Decider.map(fn, self)
  end

  define_method(:rmap_on_state) do |fn|
    Decider.rmap_on_state(fn, self)
  end

  define_method(:dimap_on_state) do |fl:, fr:|
    Decider.dimap_on_state(fl, fr, self)
  end

  define_method(:lmap_on_event) do |fn|
    Decider.lmap_on_event(fn, self)
  end

  define_method(:rmap_on_event) do |fn|
    Decider.rmap_on_event(fn, self)
  end

  define_method(:dimap_on_event) do |fl:, fr:|
    Decider.dimap_on_event(fl, fr, self)
  end

  define_method(:many) do
    Decider.many(self)
  end

  define_method(:apply) do |f|
    Decider.apply(self, f)
  end
end