Class: StateFu::Lathe

Inherits:
Object show all
Defined in:
lib/lathe.rb

Overview

A Lathe parses and a Machine definition and returns a freshly turned Machine.

It provides the means to define the arrangement of StateFu objects ( eg States and Events) which comprise a workflow, process, lifecycle, circuit, syntax, etc.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(machine, state_or_event = nil, options = {}, &block) ⇒ Lathe

you don't need to call this directly.


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# File 'lib/lathe.rb', line 16

def initialize( machine, state_or_event = nil, options={}, &block )
  @machine        = machine
  @state_or_event = state_or_event
  @options        = options.symbolize_keys!

  # extend ourself with any previously defined tools
  machine.tools.inject_into( self )

  if state_or_event
    state_or_event.apply!( options )
  end
  if block_given?
    if block.arity == 1
      if state_or_event
        yield state_or_event
      else
        raise ArgumentError
      end
    else
      instance_eval( &block )
    end
  end
end

Instance Attribute Details

#machineObject (readonly)

or contain a State or Event (a child lathe for a nested block)


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# File 'lib/lathe.rb', line 13

def machine
  @machine
end

#optionsObject (readonly)

or contain a State or Event (a child lathe for a nested block)


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# File 'lib/lathe.rb', line 13

def options
  @options
end

#state_or_eventObject (readonly) Also known as: context

or contain a State or Event (a child lathe for a nested block)


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# File 'lib/lathe.rb', line 13

def state_or_event
  @state_or_event
end

Instance Method Details

#accepted(*a, &b) ⇒ Object Also known as: on_change


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# File 'lib/lathe.rb', line 367

def accepted   *a, &b; valid_in_context State; define_hook :accepted,   *a, &b; end

#after(*a, &b) ⇒ Object


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# File 'lib/lathe.rb', line 366

def after      *a, &b; valid_in_context Event; define_hook :after,      *a, &b; end

#after_all(*a) ⇒ Object


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# File 'lib/lathe.rb', line 370

def after_all  *a, &b; valid_in_context nil;   define_hook :after_all,  *a, &b; end

#after_everythingObject


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# File 'lib/lathe.rb', line 372

def after_all  *a, &b; valid_in_context nil;   define_hook :after_all,  *a, &b; end

#before(*a, &b) ⇒ Object

Bunch of silly little methods for defining events :nodoc


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# File 'lib/lathe.rb', line 362

def before     *a, &b; valid_in_context Event; define_hook :before,     *a, &b; end

#before_all(*a, &b) ⇒ Object Also known as: before_everything


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# File 'lib/lathe.rb', line 369

def before_all *a, &b; valid_in_context nil;   define_hook :before_all, *a, &b; end

#chain(string) ⇒ Object

define chained events and states succinctly usage: chain 'state1 -event1-> state2 -event2-> state3'


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# File 'lib/lathe.rb', line 293

def chain string
  rx_word    = /([a-zA-Z0-9_]+)/
  rx_state   = /^#{rx_word}$/
  rx_event   = /^(?:-|>)#{rx_word}-?>$/
  previous   = nil
  string.split.each do |chunk|
    case chunk
    when rx_state
      current = state $1
      if previous.is_a? Event
        previous.to current
      end
    when rx_event
      current = event $1
      if previous.is_a? State
        current.from previous
      end
    else
      raise ArgumentError, "'#{chunk}' is not a valid token"
    end
    previous = current
  end
end

#connect_states(*array) ⇒ Object Also known as: connect

chain_states :a => [:b,:c], :c => :d, :c => :d chain_states :a,:b,:c,:d, :a => :c


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# File 'lib/lathe.rb', line 319

def connect_states *array
  array.flatten!
  hash = array.extract_options!.symbolize_keys!
  array.inject(nil) do |origin, target|
    state target
    if origin
      event "#{origin.to_sym}_to_#{target.to_sym}", :from => origin, :to => target
    end
    origin = target
  end
  hash.each do |origin, target|
    event "#{origin.to_sym}_to_#{target.to_sym}", :from => origin, :to => target
  end
end

#context_eventObject


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# File 'lib/lathe.rb', line 67

def context_event
  state_or_event if state_or_event.is_a?(Event)
end

#context_stateObject


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# File 'lib/lathe.rb', line 63

def context_state
  state_or_event if state_or_event.is_a?(State)
end

#cycle(name = nil, options = {}, &block) ⇒ Object

create an event from and to the current state. Creates a loop, useful (only) for hooking behaviours onto.


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# File 'lib/lathe.rb', line 223

def cycle name=nil, options={}, &block
  _state = nil
  if name.is_a?(Hash) && options.empty?
    options = name
    name    = nil
  end
  if _state = options.delete(:state)
    valid_unless_nested("when :state is supplied")
  else
    _state = state_or_event
    valid_in_context( State, "unless :state is supplied" )
  end

  name ||= options.delete :on
  name ||= "cycle_#{_state.to_sym}"
  evt = define_event( name, options, &block )
  evt.from _state
  evt.to   _state
  evt
end

#define(method_name, &block) ⇒ Object Also known as: named_proc

define a named proc


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# File 'lib/lathe.rb', line 261

def define method_name, &block
  machine.named_procs[method_name] = block
end

#event(name, options = {}, &block) ⇒ Object

Defines an event. Any options supplied will be added to the event, except :from and :to which are used to define the origin / target states. Successive invocations will update (not replace) previously defined events; origin / target states and options are always accumulated, not clobbered.

Several different styles of definition are available. Consult the specs / features for examples.


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# File 'lib/lathe.rb', line 107

def event( name, options={}, &block )
  options.symbolize_keys!
  valid_in_context( State, nil )
  if nested? && state_or_event.is_a?(State) # in state block
    targets  = options.delete(:to) || options.delete(:transitions_to)
    evt      = define_event( name, options, &block )
    evt.from state_or_event unless state_or_event.nil?
    evt.to( targets ) unless targets.nil?
    evt
  else # in master lathe
    origins = options.delete( :from )
    targets = options.delete( :to ) || options.delete(:transitions_to)
    evt     = define_event( name, options, &block )
    evt.from origins unless origins.nil?
    evt.to   targets unless targets.nil?
    evt
  end
end

#events(*args, &block) ⇒ Object Also known as: all_events, each_event

Define a series of events at once, or return and iterate over all events yet defined


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# File 'lib/lathe.rb', line 352

def events *args, &block
  valid_in_context nil, State
  each_state_or_event 'event', *args, &block
end

#execute(*a, &b) ⇒ Object


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# File 'lib/lathe.rb', line 364

def execute    *a, &b; valid_in_context Event; define_hook :execute,    *a, &b; end

#from(*args, &block) ⇒ Object

set the origin state(s) of an event (or, given a hash of symbols / arrays of symbols, set both the origins and targets) from :my_origin from [:column_a, :column_b] from :eden => :armageddon from [:beginning, :prelogue] => [:ende, :prologue]


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# File 'lib/lathe.rb', line 276

def from *args, &block
  valid_in_context Event
  state_or_event.from( *args, &block )
end

#helper(*modules) ⇒ Object

helpers are mixed into all binding / transition contexts


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# File 'lib/lathe.rb', line 77

def helper( *modules )
  machine.helper *modules
end

#initial_state(*args, &block) ⇒ Object

define the initial_state (otherwise defaults to the first state mentioned)


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# File 'lib/lathe.rb', line 249

def initial_state *args, &block
  valid_unless_nested()
  machine.initial_state= state( *args, &block)
end

#master?Boolean

is this the toplevel lathe for a machine?


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# File 'lib/lathe.rb', line 52

def master?
  !nested?
end

#master_latheObject

get the top level Lathe for the machine


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# File 'lib/lathe.rb', line 57

def master_lathe
  machine.lathe
end

#nested?Boolean Also known as: child?

a 'child' lathe is created by apply_to, to deal with nested blocks for states / events ( which are state_or_events )


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# File 'lib/lathe.rb', line 46

def nested?
  !!state_or_event
end

#on_entry(*a, &b) ⇒ Object


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# File 'lib/lathe.rb', line 365

def on_entry   *a, &b; valid_in_context State; define_hook :entry,      *a, &b; end

#on_exit(*a, &b) ⇒ Object


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# File 'lib/lathe.rb', line 363

def on_exit    *a, &b; valid_in_context State; define_hook :exit,       *a, &b; end

#requires(*args, &block) ⇒ Object Also known as: guard, must, must_be, needs

define an event or state requirement. options:

:on => :entry|:exit|array (state only) - check requirement on state entry, exit or both?
   default = :entry
:message => string|proc|proc_name_symbol - message to be returned on requirement failure.
   if a proc or symbol (named proc identifier), evaluated at runtime; a proc should
   take one argument, which is a StateFu::Transition.
:msg => alias for :message, for the morbidly terse

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# File 'lib/lathe.rb', line 188

def requires( *args, &block )
  valid_in_context Event, State
  options = args.extract_options!.symbolize_keys!
  options.assert_valid_keys :on, :message, :msg
  names   = args
  if block_given? && args.length > 1
    raise ArgumentError.new("cannot supply a block for multiple requirements")
  end
  on = nil
  names.each do |name|
    raise ArgumentError.new(name.inspect) unless name.is_a?(Symbol)
    case state_or_event
    when State
      on ||= [(options.delete(:on) || [:entry])].flatten
      state_or_event.entry_requirements << name if on.include?( :entry )
      state_or_event.exit_requirements  << name if on.include?( :exit  )
    when Event
      state_or_event.requirements << name
    end
    if block_given?
      machine.named_procs[name] = block
    end
    if msg = options.delete(:message) || options.delete(:msg)
      raise ArgumentError, msg.inspect unless [String, Symbol, Proc].include?(msg.class)
      machine.requirement_messages[name] = msg
    end
  end
end

#state(name, options = {}, &block) ⇒ Object

define a state; given a block, apply the block to a Lathe for the state


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# File 'lib/lathe.rb', line 255

def state name, options={}, &block
  valid_unless_nested()
  define_state( name, options, &block )
end

#state_event(name, options = {}, &block) ⇒ Object


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# File 'lib/lathe.rb', line 149

def state_event name, options={}, &block
  valid_in_context State
  options.symbolize_keys!
  state    = state_or_event
  targets  = options.delete(:to) || options.delete(:transitions_to)
  evt      = define_state_or_event( Event, state.own_events, name, options, &block)
  evt.from state
  evt.to(targets) unless targets.nil?
  evt
end

#states(*args, &block) ⇒ Object Also known as: all_states, each_state

Define a series of states at once, or return and iterate over all states yet defined

states :a, :b, :c, :colour => “purple” states(:ALL) do

end


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# File 'lib/lathe.rb', line 342

def states *args, &block
  valid_unless_nested()
  each_state_or_event 'state', *args, &block
end

#to(*args, &block) ⇒ Object

set the target state(s) of an event to :destination to :target_a, :target_b to [:end, :finale, :intermission]


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# File 'lib/lathe.rb', line 285

def to *args, &block
  valid_in_context Event
  state_or_event.to( *args, &block )
end

#tool(*modules, &block) ⇒ Object Also known as: extend_dsl

helpers are mixed into all binding / transition contexts


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# File 'lib/lathe.rb', line 82

def tool( *modules, &block )
  machine.tool *modules
  if block_given?
    tool = Module.new
    tool.module_eval &block
    machine.tools << tool
  end  # inject them into self for immediate use

  modules.flatten.extend( ToolArray ).inject_into( self )
end

#transitions(options = {}) ⇒ Object

compatibility methods for activemodel state machine ##############


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# File 'lib/lathe.rb', line 127

def transitions(options={})
  valid_in_context(Event)
  options.symbolize_keys!

  target  = options[:to]
  origins = options[:from]
  hook    = options[:on_transition]
  evt     = state_or_event

  if hook
    evt.lathe() { triggers hook }
  end  #
  # TODO do some type checking
  #

  if origins && target
    evt.add_to_sequence origins, target
  end
  evt
end

#will(*a, &b) ⇒ Object Also known as: fire, fires, firing, cause, causes, triggers, trigger


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# File 'lib/lathe.rb', line 378

def will *a, &b
  valid_in_context State, Event
  case state_or_event
  when State
    define_hook :entry, *a, &b
  when Event
    define_hook :execute, *a, &b
  end
end