Class: SXP::Pair

Inherits:
Object show all
Defined in:
lib/sxp/pair.rb

Direct Known Subclasses

List

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(head = nil, tail = nil) ⇒ Pair

Returns a new instance of Pair.

Parameters:

  • head (Object) (defaults to: nil)
  • tail (Object) (defaults to: nil) 


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# File 'lib/sxp/pair.rb', line 14

def initialize(head = nil, tail = nil)
  @head, @tail = head, tail
end

Instance Attribute Details

#head ⇒ Object

Returns:



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# File 'lib/sxp/pair.rb', line 6

def head
  @head
end

#tail ⇒ Object

Returns:



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# File 'lib/sxp/pair.rb', line 9

def tail
  @tail
end

Instance Method Details

#dotted? ⇒ Boolean

Returns ‘true` if the tail of this pair is not `nil` or another pair.

Returns:

  • (Boolean)

See Also:

  • SXP::Pair.https:/srfihttps:/srfi.schemershttps:/srfi.schemers.org/srfi-1/srfi-1https:/srfi.schemers.org/srfi-1/srfi-1.htmlhttps:/srfi.schemers.org/srfi-1/srfi-1.html#ImproperLists


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# File 'lib/sxp/pair.rb', line 31

def dotted?
  !proper?
end

#empty? ⇒ Boolean

Returns ‘true` if the head and tail of this pair are both `nil`.

Returns:

  • (Boolean) 


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# File 'lib/sxp/pair.rb', line 22

def empty?
  head.nil? && tail.nil?
end

#inspect ⇒ String

Returns a developer-friendly representation of this pair.

Returns:



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# File 'lib/sxp/pair.rb', line 56

def inspect
  case
    when tail.nil?
      "(#{head.inspect})"
    else
      "(#{head.inspect} . #{tail.inspect})"
  end
end

#proper? ⇒ Boolean

Returns ‘true` if the tail of this pair is `nil` or another pair.

Returns:

  • (Boolean)

See Also:

  • SXP::Pair.https:/srfihttps:/srfi.schemershttps:/srfi.schemers.org/srfi-1/srfi-1https:/srfi.schemers.org/srfi-1/srfi-1.htmlhttps:/srfi.schemers.org/srfi-1/srfi-1.html#ImproperLists


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# File 'lib/sxp/pair.rb', line 40

def proper?
  tail.nil? || tail.is_a?(Pair)
end

#to_a ⇒ Array

Returns an array representation of this pair.

Returns:



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# File 'lib/sxp/pair.rb', line 48

def to_a
  [head, tail]
end