Class: Porolog::Tail

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

Overview

A Porolog::Tail is used to represent the tail of a list.

It corresponds to the use of the splat operator within an Array.

Author:

  • Luis Esteban

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(value = UNKNOWN_TAIL) ⇒ Tail

Creates a new Tail for an Array.

Parameters:

  • value (Object) (defaults to: UNKNOWN_TAIL) —

    the value of the tail.



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# File 'lib/porolog/tail.rb', line 22

def initialize(value = UNKNOWN_TAIL)
  @value = value
end

Instance Attribute Details

#value ⇒ Object

Returns the value of the Tail. The optional arguments are ignored; this is for polymorphic compatibility with Porolog::Value and Porolog::Variable, which are used to prevent inifinite recursion.

Returns:

  • (Object) —

    the value of the Tail.



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# File 'lib/porolog/tail.rb', line 18

class Tail
  
  # Creates a new Tail for an Array.
  # @param value [Object] the value of the tail.
  def initialize(value = UNKNOWN_TAIL)
    @value = value
  end
  
  # @return [Symbol] the type of the Tail, which should be :tail.
  def type
    :tail
  end
  
  # Returns the value of the Tail.
  # The optional arguments are ignored; this is for polymorphic compatibility with Porolog::Value and Porolog::Variable,
  # which are used to prevent inifinite recursion.
  # @return [Object] the value of the Tail.
  def value(*)
    @value
  end
  
  # @return [String] pretty representation.
  def inspect
    "*#{@value.inspect}"
  end
  
  # @return [Array] embedded variables.
  def variables
    @value.variables
  end
  
  # @param other [Object, #value]
  # @return [Boolean] whether the value of the Tail is equal to the value of another Object.
  def ==(other)
    @value == other.value
  end
  
end

Instance Method Details

#==(other) ⇒ Boolean

Returns whether the value of the Tail is equal to the value of another Object.

Parameters:

Returns:

  • (Boolean) —

    whether the value of the Tail is equal to the value of another Object.



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# File 'lib/porolog/tail.rb', line 51

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

#inspect ⇒ String

Returns pretty representation.

Returns:

  • (String) —

    pretty representation.



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# File 'lib/porolog/tail.rb', line 40

def inspect
  "*#{@value.inspect}"
end

#type ⇒ Symbol

Returns the type of the Tail, which should be :tail.

Returns:

  • (Symbol) —

    the type of the Tail, which should be :tail.



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# File 'lib/porolog/tail.rb', line 27

def type
  :tail
end

#variables ⇒ Array

Returns embedded variables.

Returns:

  • (Array) —

    embedded variables.



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# File 'lib/porolog/tail.rb', line 45

def variables
  @value.variables
end