Class: StateMachine

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

Overview

Usage:

require 'rms'
class Blub < StateMachine
    def initialize
        super :welcome
        @name = 'World'
    end
    def welcome_enter(env)
        puts 'Enter Name: '
    end
    def welcome(env)
        @name = env[:line] if env[:line] != ''
        puts "Hello #{@name}"
    end
end
bla = Blub.new
# prints out 'Enter Name: '
loop do
    line = gets.strip
    bla.process({:line => line})
end

Direct Known Subclasses

Blub

Instance Method Summary collapse

Constructor Details

#initialize(start_state = :start, error_state = :error) ⇒ StateMachine

Returns a new instance of StateMachine.



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# File 'lib/rms.rb', line 26

def initialize(start_state=:start, error_state=:error)
    @error_state = error_state
    @state = :none
    switch(start_state, {})
end

Instance Method Details

#process(env) ⇒ Object 



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# File 'lib/rms.rb', line 45

def process(env)
    unless @state_method
        begin
            @state_method = method(@state)
        rescue NameError
            switch(@error_state, env)
        end
    end
    @state_method.call(env)
end

#switch(new_state, env) ⇒ Object 



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# File 'lib/rms.rb', line 32

def switch(new_state, env)
    # call the enter method...
    begin
        m_enter = method((new_state.to_s + '_enter').to_sym)
        m_enter.call(env)
    rescue NameError
        # nope didnt exist
    end
    # now check if there is such a method(with the name new_state)
    @state_method = method(new_state.to_sym)
    @state = new_state.to_sym
end