Module: Enumerators

Defined in:
lib/enumerators.rb

Instance Method Summary collapse

Instance Method Details

#character_enumerator(string) ⇒ Object 



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# File 'lib/enumerators.rb', line 38

def character_enumerator(string)
  Enumerator.new do |y|
    index = 0
    loop do
      raise StopIteration.new unless index < string.size
      y << string[index]
      index = index + 1
    end
  end.lazy
end

#empty_enumerator ⇒ Object 



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# File 'lib/enumerators.rb', line 71

def empty_enumerator
  [].lazy
end

#enumerator(fn, init) ⇒ Object 



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# File 'lib/enumerators.rb', line 15

def enumerator(fn, init)
  Enumerator.new do |y|
    value = init
    y << value
    loop do
      value = fn.(value)
      y << value
    end
  end.lazy
end

#flatten_enumerator(enumerator) ⇒ Object 



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# File 'lib/enumerators.rb', line 49

def flatten_enumerator(enumerator)
  Enumerator.new do |y|
    current_enumerator = empty_enumerator

    loop do
      until has_next(current_enumerator)
        unless has_next(enumerator)
          current_enumerator = empty_enumerator
          break
        end
        current_enumerator = enumerator.next.enumerator
      end

      if has_next(current_enumerator)
        y << current_enumerator.next
      else
        raise StopIteration.new
      end
    end
  end.lazy
end

#has_next(e) ⇒ Object 



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# File 'lib/enumerators.rb', line 6

def has_next(e)
  begin
    e.peek
    true
  rescue StopIteration
    false
  end
end

#repeat_enumerator(value) ⇒ Object 



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# File 'lib/enumerators.rb', line 26

def repeat_enumerator(value)
  Enumerators.repeat_fn_enumerator(returns(value))
end

#repeat_fn_enumerator(fn) ⇒ Object 



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# File 'lib/enumerators.rb', line 30

def repeat_fn_enumerator(fn)
  Enumerator.new do |y|
    loop do
      y << fn.()
    end
  end.lazy
end

#reverse(e) ⇒ Object 



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# File 'lib/enumerators.rb', line 2

def reverse(e)
  e.reverse_each
end