Class: Pushdown::Transition::Replace

Inherits:
Pushdown::Transition show all
Defined in:
lib/pushdown/transition/replace.rb

Overview

A replace transition – remove all currents states from the stack and add a different one.

Instance Attribute Summary collapse

Attributes inherited from Pushdown::Transition

#name

Instance Method Summary collapse

Methods inherited from Pushdown::Transition

inherited, #type_name

Constructor Details

#initialize(name, state_class, data = nil) ⇒ Replace

Create a transition that will Replace all the states on the current stack with an instance of the given state_class.



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# File 'lib/pushdown/transition/replace.rb', line 13

def initialize( name, state_class, data=nil )
	super( name )

	@state_class = state_class
	@data = data
end

Instance Attribute Details

#data ⇒ Object (readonly)

The data object to pass to the #state_class’s constructor



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# File 'lib/pushdown/transition/replace.rb', line 31

def data
  @data
end

#state_class ⇒ Object (readonly)

The State to replace the stack members with.



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# File 'lib/pushdown/transition/replace.rb', line 27

def state_class
  @state_class
end

Instance Method Details

#apply(stack) ⇒ Object

Apply the transition to the given stack.



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# File 'lib/pushdown/transition/replace.rb', line 35

def apply( stack )
	state = self.state_class.new( self.data )

	self.log.debug "replacing current state with a new state: %p" % [ state ]
	while ( old_state = stack.pop )
		old_state.on_stop
	end

	stack.push( state )
	state.on_start

	return stack
end