Class: Stages::Stage

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/stage_base.rb

Direct Known Subclasses

Cache, Count, Each, Emit, Exhaust, ExhaustCount, Feeder, Limit, Map, Select, Unique, Wrap

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(&block) ⇒ Stage

Returns a new instance of Stage.



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

def initialize(&block)
  @block = block
  initialize_loop
end

Instance Attribute Details

#source ⇒ Object

Returns the value of attribute source.



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# File 'lib/stage_base.rb', line 4

def source
  @source
end

Instance Method Details

#die ⇒ Object 



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# File 'lib/stage_base.rb', line 48

def die
  loop do
    output :stages_eos
  end
end

#done? ⇒ Boolean

Returns:

  • (Boolean) 


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

def done?
  return true if @done
  return false if @cached_value != :stages_empty_cache
  next_value = @fiber_delegate.resume
  if next_value == :stages_eos
    @done = true
    @cached_value = :stages_empty_cache
    return true
  end
  @cached_value = next_value
  return false
end

#drop_leftmost! ⇒ Object 



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# File 'lib/stage_base.rb', line 101

def drop_leftmost!
  if @source.end?
    @source = nil
  else
    @source.drop_leftmost!
  end
end

#each(&block) ⇒ Object 



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# File 'lib/stage_base.rb', line 68

def each(&block)
  to_enum.each(&block)
end

#end? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/stage_base.rb', line 109

def end?
  @source.nil?
end

#handle_value(value) ⇒ Object 



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# File 'lib/stage_base.rb', line 72

def handle_value(value)
  output value
end

#initialize_loop ⇒ Object 



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# File 'lib/stage_base.rb', line 11

def initialize_loop
  @done = false
  @cached_value = :stages_empty_cache
  @fiber_delegate = Fiber.new do
    process
    @done = true
    die
  end
end

#input ⇒ Object 



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# File 'lib/stage_base.rb', line 80

def input
  source.nil? ? :stages_eos : source.run
end

#length ⇒ Object 



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# File 'lib/stage_base.rb', line 113

def length
  if source
    source.length + 1
  else
    1
  end
end

#output(value) ⇒ Object 



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# File 'lib/stage_base.rb', line 84

def output(value)
  Fiber.yield value
end

#process ⇒ Object 



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# File 'lib/stage_base.rb', line 54

def process
  while !source_empty?
    handle_value input
  end
end

#reset ⇒ Object 



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# File 'lib/stage_base.rb', line 43

def reset
  initialize_loop
  @source.reset if @source
end

#root_source ⇒ Object

root_source lets you add to existing pipelines the result is always the rightmost stage so adding things to it is problematic



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# File 'lib/stage_base.rb', line 97

def root_source
  source.nil? ? self : source.root_source
end

#run ⇒ Object 



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# File 'lib/stage_base.rb', line 21

def run
  if @cached_value != :stages_empty_cache
    v = @cached_value
    @cached_value = :stages_empty_cache
    return v
  end
  @fiber_delegate.resume
end

#source_empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/stage_base.rb', line 76

def source_empty?
  (source.nil? || source.done?)
end

#to_enum ⇒ Object 



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# File 'lib/stage_base.rb', line 60

def to_enum
  Enumerator.new do |y|
    while !done?
      y << run
    end
  end
end

#|(other) ⇒ Object 



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# File 'lib/stage_base.rb', line 88

def |(other)
  return self if other.nil?
  other.root_source.source = self
  other
end