Class: Immutable::Queue

Inherits:

Object

• Object
• Immutable::Queue

show all

Includes:

Headable

Defined in:

lib/immutable/queue.rb

Overview

Class Method Summary (collapse)

• + (Queue) [](*elements)

  Creates a new queue populated with the given objects.

• + (Queue) empty

  Returns an empty queue.

Instance Method Summary (collapse)

• - (true, false) empty?

  Returns whether self is empty.

• - (Object) head

  Returns the first element of self.

• - (Queue) initialize(front, rear, schedule) constructor

  Queue.new is for internal use only.

• - (Queue) snoc(x) (also: #push)

  Adds a new element at the end of self.

• - (Queue) tail

  Returns the elements after the head of self.

Methods included from Headable

#==, #[], #each, #each_index, #eql?, #fetch, #find, #first, #foldl, #foldl1, #foldr, #foldr1, #hash, #index, #inspect, #null?, #rindex, #shift, #to_list

Methods included from Foldable

#foldl, #length, #product, #sum

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# File 'lib/immutable/queue.rb', line 11

def initialize(front, rear, schedule)
  @front = front
  @rear = rear
  @schedule = schedule
end

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# File 'lib/immutable/queue.rb', line 28

def self.[](*elements)
  elements.inject(empty, &:snoc)
end

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# File 'lib/immutable/queue.rb', line 20

def self.empty
  new(Stream.empty, Nil, Stream.empty)
end

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# File 'lib/immutable/queue.rb', line 35

def empty?
  @front.empty?
end

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# File 'lib/immutable/queue.rb', line 53

def head
  @front.head
end

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# File 'lib/immutable/queue.rb', line 43

def snoc(x)
  queue(@front, Cons[x, @rear], @schedule)
end

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# File 'lib/immutable/queue.rb', line 61

def tail
  if @front.empty?
    raise EmptyError
  else
    queue(@front.tail, @rear, @schedule)
  end
end