Class: Fae::FiniteAutomata

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

Overview

The main class that drives the Finite Automata evaluation.

Takes in a language, states, and strings, and checks them to validate a state diagram.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(language, description) ⇒ FiniteAutomata

Initializes a new instance of the FiniteAutomata.



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# File 'lib/fae/finite_automata.rb', line 14

def initialize(language, description)
  @states = []
  @strings = []
  @invalids = []
  @language = language
  @description = description
end

Instance Attribute Details

#description ⇒ Object (readonly)

Returns the value of attribute description.



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# File 'lib/fae/finite_automata.rb', line 8

def description
  @description
end

#language ⇒ Object (readonly)

Returns the value of attribute language.



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# File 'lib/fae/finite_automata.rb', line 8

def language
  @language
end

#states ⇒ Object (readonly)

Returns the value of attribute states.



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# File 'lib/fae/finite_automata.rb', line 8

def states
  @states
end

#strings ⇒ Object (readonly)

Returns the value of attribute strings.



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# File 'lib/fae/finite_automata.rb', line 8

def strings
  @strings
end

Instance Method Details

#add_states(states) ⇒ Object

Adds strings to check against when evaluating.



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# File 'lib/fae/finite_automata.rb', line 41

def add_states(states)
  states.each do |state|
    add_state(state)
  end
end

#add_string(string) ⇒ Object

Adds a single string to the strings array.



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# File 'lib/fae/finite_automata.rb', line 34

def add_string(string)
  @strings << string
end

#add_strings(strings) ⇒ Object

Adds strings to check against when evaluating.



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# File 'lib/fae/finite_automata.rb', line 25

def add_strings(strings)
  strings.each do |string|
    @strings << string
  end
end

#difference(fa) ⇒ Object

Generates the finite automata for the difference of two different finite automatas.



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# File 'lib/fae/finite_automata.rb', line 84

def difference(fa)
  perform_set_operation(:difference, fa)
end

#evaluate! ⇒ Object

Runs the evaluation on the finite automata.



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# File 'lib/fae/finite_automata.rb', line 89

def evaluate!
  @invalids = []
  if (@states.length == 0)
    raise "You must add some states to your Finite Automata before checking strings"
  end

  puts """Evaluating strings for #{@description} using language #{@language.characters}".colorize(:yellow)
  @strings.each do |string|
    valid = evaluate_string(string)
    if (!valid)
      @invalids << string
    end
  end

  num_invalid = @invalids.length
  if (num_invalid > 0)
    puts "State diagram may be incorrect for #{@description}".colorize(:red)
    puts "\nA total of #{num_invalid} string#{'s' if num_invalid != 1} did not meet your expectations:\n"

    @invalids.each do |string|
      expected_string = string.expected ? "valid".colorize(:green) : "invalid".colorize(:red)
      puts "* You expected the string '#{string.colorize(:blue)}' to be #{expected_string}"
    end
    puts "\nIf these expectations are correct, then your state diagram needs revising. Otherwise, you've simply expected the wrong values."
  else
    puts "State diagram is correct.".colorize(:green)
  end
  puts
end

#get_state(name) ⇒ Object

Retrieves a state from this finite automata by name.



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# File 'lib/fae/finite_automata.rb', line 50

def get_state(name)
  retrieved_state = nil
  @states.each do |state|
    if (state.name == name)
      retrieved_state = state
      break
    end
  end
  if (retrieved_state.nil?)
    raise "State #{name} was not found in this Finite Automata. Ensure that all states have outputs for #{@language.characters}"
  end
  return retrieved_state
end

#intersection(fa) ⇒ Object

Generates the finite automata for the intersection of two different finite automatas.



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# File 'lib/fae/finite_automata.rb', line 68

def intersection(fa)
  perform_set_operation(:intersection, fa)
end

#to_s ⇒ Object 



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# File 'lib/fae/finite_automata.rb', line 119

def to_s
  output = ""
  output << "Description: ".colorize(:yellow) + @description
  output << "\nLanguage: ".colorize(:yellow) + language.characters.to_s
  output << "\nStates:".colorize(:yellow)
  @states.each do |state|
    output << "\n  State #{state.name}: ".colorize(:blue)
    state.paths.keys.each do |key|
      output << "\n    #{'~'.colorize(:yellow)} #{key} #{'->'.colorize(:light_black)} #{state.paths[key]}"
    end
    accepting = state.accepting ? "accepting".colorize(:green) : "not accepting".colorize(:red)
    output << "\n    #{'~'.colorize(:yellow)} #{accepting}"
  end
  return output
end

#union(fa) ⇒ Object

Generates the finite automata for the union of two different finite automatas.



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# File 'lib/fae/finite_automata.rb', line 76

def union(fa)
  perform_set_operation(:union, fa)
end