Module: Immutable::Consable

Includes:
Headable
Included in:
Deque, List, OutputRestrictedDeque, Stream
Defined in:
lib/immutable/consable.rb

Defined Under Namespace

Modules: ClassMethods

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Headable

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

Methods included from Foldable

#foldl, #length, #product, #sum

Class Method Details

.included(c) ⇒ Object 



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# File 'lib/immutable/consable.rb', line 68

def self.included(c)
  c.extend(ClassMethods)
end

Instance Method Details

#+(xs) ⇒ Consable

Appends two Consable objects self and xs.

Parameters:

  • xs (Consable) —

    the Consable object to append.

Returns:



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# File 'lib/immutable/consable.rb', line 101

def +(xs)
  foldr(xs) { |y, ys| Cons(y, ys) }
end

#cons(x) ⇒ Consable

Adds a new element at the head of self. A class including Immutable::Consable must implement this method.

Parameters:

  • x (Object) —

    the element to add.

Returns:

Raises:

  • (NotImplementedError) 


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# File 'lib/immutable/consable.rb', line 77

def cons(x)
  raise NotImplementedError
end

#drop(n) ⇒ Consable

Returns the suffix of self after the first n elements, or an empty Consable object if n > self.length.

Parameters:

  • n (Integer) —

    the number of elements to drop.

Returns:

  • (Consable) —

    the suffix of self after the first n elements.



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# File 'lib/immutable/consable.rb', line 221

def drop(n)
  if empty?
    empty
  else
    if n > 0
      tail.drop(n - 1)
    else
      self
    end
  end
end

#drop_while(&block) ⇒ Consable

Returns the suffix remaining after self.take_while(&block).

Returns:

  • (Consable) —

    the suffix of the elements of self.



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# File 'lib/immutable/consable.rb', line 253

def drop_while(&block)
  if empty?
    empty
  else
    if yield(head)
      tail.drop_while(&block)
    else
      self
    end
  end
end

#filter ⇒ Consable

Returns the elements in self for which the given block evaluates to true.

Returns:

  • (Consable) —

    the elements that satisfies the condition.



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# File 'lib/immutable/consable.rb', line 269

def filter
  foldr(empty) { |x, xs|
    if yield(x)
      Cons(x, xs)
    else
      xs
    end
  }
end

#flat_map ⇒ Consable Also known as: concat_map, bind

Returns the Consable object obtained by concatenating the results of the given block for each element in self.

Returns:

  • (Consable) —

    the obtained Consable object.



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# File 'lib/immutable/consable.rb', line 192

def flat_map
  foldr(empty) { |x, xs| safe_append(yield(x), xs) }
end

#flatten ⇒ Consable Also known as: concat

Concatenates a Consable object of Consable objects.

Returns:

  • (Consable) —

    the concatenated Consable object.



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# File 'lib/immutable/consable.rb', line 182

def flatten
  foldr(empty) { |x, xs| safe_append(x, xs) }
end

#intercalate(xs) ⇒ Consable

Returns a new Consable object obtained by inserting xs in between the Consable objects in self and concatenates the result. xss.intercalate(xs) is equivalent to xss.intersperse(xs).flatten.

Parameters:

  • xs (Consable) —

    the Consable object to insert between Consable objects.

Returns:

  • (Consable) —

    the new Consable object.



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# File 'lib/immutable/consable.rb', line 148

def intercalate(xs)
  intersperse(xs).flatten
end

#intersperse(sep) ⇒ Consable

Returns a new Consable object obtained by inserting sep in between the elements of self.

Parameters:

  • sep (Object) —

    the object to insert between elements.

Returns:

  • (Consable) —

    the new Consable object.



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# File 'lib/immutable/consable.rb', line 133

def intersperse(sep)
  if empty?
    empty
  else
    Cons(head, tail.prepend_to_all(sep))
  end
end

#map(&block) ⇒ Consable

Returns the Consable object obtained by applying the given block to each element in self.

Returns:

  • (Consable) —

    the obtained Consable object.



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# File 'lib/immutable/consable.rb', line 109

def map(&block)
  rev_map(&block).reverse
end

#prepend(x) ⇒ Consable

Same as #cons. This method just calls #cons.

Parameters:

  • x (Object) —

    the element to add.

Returns:



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# File 'lib/immutable/consable.rb', line 93

def prepend(x)
  cons(x)
end

#rev_map ⇒ Consable

Returns the Consable object obtained by applying the given block to each element in self in reverse order.

Returns:

  • (Consable) —

    the obtained Consable object.



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# File 'lib/immutable/consable.rb', line 117

def rev_map
  foldl(empty) { |xs, x| Cons(yield(x), xs) }
end

#reverse ⇒ Consable

Returns the elements of self in reverse order.

Returns:

  • (Consable) —

    the reversed Consable object.



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# File 'lib/immutable/consable.rb', line 124

def reverse
  foldl(empty) { |x, y| Cons(y, x) }
end

#subsequences ⇒ Consable<Consable>

Returns the Consable object of all subsequences of self.

Returns:



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# File 'lib/immutable/consable.rb', line 175

def subsequences
  Cons(empty, nonempty_subsequences)
end

#take(n) ⇒ Consable

Returns the first n elements of self, or all the elements of self if n > self.length.

Parameters:

  • n (Integer) —

    the number of elements to take.

Returns:

  • (Consable) —

    the first n elements of self.



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# File 'lib/immutable/consable.rb', line 204

def take(n)
  if empty?
    empty
  else
    if n <= 0
      empty
    else
      Cons(head, tail.take(n - 1))
    end
  end
end

#take_while(&block) ⇒ Consable

Returns the longest prefix of the elements of self for which block evaluates to true.

Returns:

  • (Consable) —

    the prefix of the elements of self.



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# File 'lib/immutable/consable.rb', line 237

def take_while(&block)
  if empty?
    empty
  else
    if yield(head)
      Cons(head, tail.take_while(&block))
    else
      empty
    end
  end
end

#transpose ⇒ Consable

Transposes the rows and columns of self. For example:

p List[List[1, 2, 3], List[4, 5, 6]].transpose
#=> List[List[1, 4], List[2, 5], List[3, 6]]

Returns:

  • (Consable) —

    the transposed Consable object.



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# File 'lib/immutable/consable.rb', line 158

def transpose
  if empty?
    empty
  else
    if head.empty?
      tail.transpose
    else
      t = tail.filter { |x| !x.empty? }
      Cons(Cons(head.head, t.map(&:head)),
           Cons(head.tail, t.map(&:tail)).transpose)
    end
  end
end

#unshift(x) ⇒ Consable

Same as #cons. This method just calls #cons.

Parameters:

  • x (Object) —

    the element to add.

Returns:



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# File 'lib/immutable/consable.rb', line 85

def unshift(x)
  cons(x)
end

#zip(*xss) ⇒ Consable

Takes zero or more lists and returns a new Consable object in which each element is an array of the corresponding elements of self and the input Consable objects.

Parameters:

  • xss (Array<Consable>) —

    the input Consable objects.

Returns:

  • (Consable) —

    the new Consable object.



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# File 'lib/immutable/consable.rb', line 285

def zip(*xss)
  if empty?
    empty
  else
    heads = xss.map { |xs| xs.empty? ? nil : xs.head }
    tails = xss.map { |xs| xs.empty? ? empty : xs.tail }
    Cons([head, *heads], tail.zip(*tails))
  end
end

#zip_with(*xss, &block) ⇒ Consable

Takes zero or more Consable objects and returns the Consable object obtained by applying the given block to an array of the corresponding elements of self and the input Consable objects. xs.zip_with(*yss, &block) is equivalent to xs.zip(*yss).map(&block).

Parameters:

  • xss (Array<Consable>) —

    the input Consable objects.

Returns:

  • (Consable) —

    the new Consable object.



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# File 'lib/immutable/consable.rb', line 303

def zip_with(*xss, &block)
  if empty?
    empty
  else
    heads = xss.map { |xs| xs.null? ? nil : xs.head }
    tails = xss.map { |xs| xs.null? ? empty : xs.tail }
    Cons(yield(head, *heads), tail.zip_with(*tails, &block))
  end
end