Class: Porolog::Value

Inherits:
Object show all
Defined in:
lib/porolog/value.rb

Overview

A Porolog::Value combines a value with a goal so that when the goal is closed, the value can be uninstantiated at the same time.

Defined Under Namespace

Classes: Error, GoalError

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(value, goal) ⇒ Porolog::Value

Returns the Value.

Parameters:

  • value (Object) —

    the value to be associated with a Goal.

  • goal (Porolog::Goal) —

    the Goal to be associated.

Raises:



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# File 'lib/porolog/value.rb', line 32

def initialize(value, goal)
  raise GoalError, "Not a Goal: #{goal.inspect}" unless goal.is_a?(Goal)
  
  @value = value
  @value = value.value if value.is_a?(Value)
  @goal  = goal
  
  @instantiations = []
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &block) ⇒ Object

Passes on methods to the Value’s value.



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# File 'lib/porolog/value.rb', line 72

def method_missing(method, *args, &block)
  @value.send(method, *args, &block)
end

Instance Attribute Details

#goal ⇒ Porolog::Goal

Returns The goal in which the value was instantiated.

Returns:

  • (Porolog::Goal) —

    The goal in which the value was instantiated.



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# File 'lib/porolog/value.rb', line 20

class Value
  
  # Error class for rescuing or detecting any Value error.
  class Error     < PorologError ; end
  # Error class indicating that the supplied goal is not actually a goal.
  class GoalError < Error        ; end
  
  attr_accessor :goal, :instantiations
  
  # @param value [Object] the value to be associated with a Goal.
  # @param goal [Porolog::Goal] the Goal to be associated.
  # @return [Porolog::Value] the Value.
  def initialize(value, goal)
    raise GoalError, "Not a Goal: #{goal.inspect}" unless goal.is_a?(Goal)
    
    @value = value
    @value = value.value if value.is_a?(Value)
    @goal  = goal
    
    @instantiations = []
  end
  
  # Pretty presentation.
  # @return [String] the inspect of the value prefixed by the goal id.
  def inspect
    "#{@goal.myid}.#{@value.inspect}"
  end
  
  # Pretty presentation with instantiations and indexes.
  # This method is for polymorphic compatibility with Porolog::Variable.
  # It used by Porolog::Goal#inspect_variables.
  # @param visited [Array] the values already visited (to prevent infinite recursion).
  # @param depth [Integer] the level of indentation that shows containment.
  # @param index [Integer,Symbol,Array] the index into this value.
  # @param self_index [Integer,Symbol,Array] the index of which this value belongs.
  # @return [String] the inspect of the value in the context of the variables of a goal.
  def inspect_with_instantiations(visited = [], depth = 0, index = nil, self_index = nil)
    index_str = index && "[#{index.inspect}]" || ''
    prefix    = self_index&.inspect || ''
    
    "#{'  ' * depth}#{prefix}#{inspect}#{index_str}"
  end
  
  # Uninstantiate the Value.
  # @return [Boolean] true
  def remove
    @instantiations.dup.each(&:remove)
    @instantiations[0..-1] = []
    true
  end
  
  # Passes on methods to the Value's value.
  def method_missing(method, *args, &block)
    @value.send(method, *args, &block)
  end
  
  # Responds to all the Value's value methods as well as its own.
  # @return [Boolean] whether the value responds to the method.
  def respond_to?(method, include_all = false)
    @value.respond_to?(method, include_all) || super
  end
  
  # @return [Object] the value of the Value.
  def value(*)
    @value
  end
  
  # @return [Symbol] the type of the value.
  def type
    @value.type
  end
  
  # Compares Values for equality.
  # @return [Boolean] whether the Values' values are equal.
  def ==(other)
    @value == other.value
  end
  
  # @return [Array<Porolog::Variable,Symbol>] variables embedded in the value.
  def variables
    @value.variables
  end
  
end

#instantiations ⇒ Array<Porolog::Instantiation>

Returns Instantiations of this value.

Returns:



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# File 'lib/porolog/value.rb', line 20

class Value
  
  # Error class for rescuing or detecting any Value error.
  class Error     < PorologError ; end
  # Error class indicating that the supplied goal is not actually a goal.
  class GoalError < Error        ; end
  
  attr_accessor :goal, :instantiations
  
  # @param value [Object] the value to be associated with a Goal.
  # @param goal [Porolog::Goal] the Goal to be associated.
  # @return [Porolog::Value] the Value.
  def initialize(value, goal)
    raise GoalError, "Not a Goal: #{goal.inspect}" unless goal.is_a?(Goal)
    
    @value = value
    @value = value.value if value.is_a?(Value)
    @goal  = goal
    
    @instantiations = []
  end
  
  # Pretty presentation.
  # @return [String] the inspect of the value prefixed by the goal id.
  def inspect
    "#{@goal.myid}.#{@value.inspect}"
  end
  
  # Pretty presentation with instantiations and indexes.
  # This method is for polymorphic compatibility with Porolog::Variable.
  # It used by Porolog::Goal#inspect_variables.
  # @param visited [Array] the values already visited (to prevent infinite recursion).
  # @param depth [Integer] the level of indentation that shows containment.
  # @param index [Integer,Symbol,Array] the index into this value.
  # @param self_index [Integer,Symbol,Array] the index of which this value belongs.
  # @return [String] the inspect of the value in the context of the variables of a goal.
  def inspect_with_instantiations(visited = [], depth = 0, index = nil, self_index = nil)
    index_str = index && "[#{index.inspect}]" || ''
    prefix    = self_index&.inspect || ''
    
    "#{'  ' * depth}#{prefix}#{inspect}#{index_str}"
  end
  
  # Uninstantiate the Value.
  # @return [Boolean] true
  def remove
    @instantiations.dup.each(&:remove)
    @instantiations[0..-1] = []
    true
  end
  
  # Passes on methods to the Value's value.
  def method_missing(method, *args, &block)
    @value.send(method, *args, &block)
  end
  
  # Responds to all the Value's value methods as well as its own.
  # @return [Boolean] whether the value responds to the method.
  def respond_to?(method, include_all = false)
    @value.respond_to?(method, include_all) || super
  end
  
  # @return [Object] the value of the Value.
  def value(*)
    @value
  end
  
  # @return [Symbol] the type of the value.
  def type
    @value.type
  end
  
  # Compares Values for equality.
  # @return [Boolean] whether the Values' values are equal.
  def ==(other)
    @value == other.value
  end
  
  # @return [Array<Porolog::Variable,Symbol>] variables embedded in the value.
  def variables
    @value.variables
  end
  
end

Instance Method Details

#==(other) ⇒ Boolean

Compares Values for equality.

Returns:

  • (Boolean) —

    whether the Values’ values are equal.



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# File 'lib/porolog/value.rb', line 94

def ==(other)
  @value == other.value
end

#inspect ⇒ String

Pretty presentation.

Returns:

  • (String) —

    the inspect of the value prefixed by the goal id.



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# File 'lib/porolog/value.rb', line 44

def inspect
  "#{@goal.myid}.#{@value.inspect}"
end

#inspect_with_instantiations(visited = [], depth = 0, index = nil, self_index = nil) ⇒ String

Pretty presentation with instantiations and indexes. This method is for polymorphic compatibility with Porolog::Variable. It used by Porolog::Goal#inspect_variables.

Parameters:

  • visited (Array) (defaults to: []) —

    the values already visited (to prevent infinite recursion).

  • depth (Integer) (defaults to: 0) —

    the level of indentation that shows containment.

  • index (Integer, Symbol, Array) (defaults to: nil) —

    the index into this value.

  • self_index (Integer, Symbol, Array) (defaults to: nil) —

    the index of which this value belongs.

Returns:

  • (String) —

    the inspect of the value in the context of the variables of a goal.



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# File 'lib/porolog/value.rb', line 56

def inspect_with_instantiations(visited = [], depth = 0, index = nil, self_index = nil)
  index_str = index && "[#{index.inspect}]" || ''
  prefix    = self_index&.inspect || ''
  
  "#{'  ' * depth}#{prefix}#{inspect}#{index_str}"
end

#remove ⇒ Boolean

Uninstantiate the Value.

Returns:

  • (Boolean) —

    true



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# File 'lib/porolog/value.rb', line 65

def remove
  @instantiations.dup.each(&:remove)
  @instantiations[0..-1] = []
  true
end

#respond_to?(method, include_all = false) ⇒ Boolean

Responds to all the Value’s value methods as well as its own.

Returns:

  • (Boolean) —

    whether the value responds to the method.



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# File 'lib/porolog/value.rb', line 78

def respond_to?(method, include_all = false)
  @value.respond_to?(method, include_all) || super
end

#type ⇒ Symbol

Returns the type of the value.

Returns:

  • (Symbol) —

    the type of the value.



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# File 'lib/porolog/value.rb', line 88

def type
  @value.type
end

#value ⇒ Object

Returns the value of the Value.

Returns:

  • (Object) —

    the value of the Value.



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# File 'lib/porolog/value.rb', line 83

def value(*)
  @value
end

#variables ⇒ Array<Porolog::Variable,Symbol>

Returns variables embedded in the value.

Returns:



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# File 'lib/porolog/value.rb', line 99

def variables
  @value.variables
end