Class: Monadt::Monad

Inherits:
Object
  • Object
show all
Defined in:
lib/monadt.rb,
lib/monadt/monad.rb

Class Method Summary collapse

Class Method Details

.do_m(klass, &blk) ⇒ Object 



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# File 'lib/monadt/monad.rb', line 21

def do_m(klass, &blk)
  e = Enumerator.new do |y|
    m_obj = Internal::MonadObj.new klass, y
    blk.call(m_obj)
  end
  do_m_recur(klass, e)
end

.do_m_recur(klass, e) ⇒ Object 



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# File 'lib/monadt/monad.rb', line 29

def do_m_recur(klass, e)
  begin
    ma = e.next
  rescue StopIteration => ex
    return ex.result
  end
  klass.bind(ma) do |a|
    e.feed a
    do_m_recur(klass, e)
  end
end

.either(&blk) ⇒ Object 



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# File 'lib/monadt.rb', line 18

def either(&blk)
  do_m(EitherM, &blk)
end

.maybe(&blk) ⇒ Object 



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# File 'lib/monadt.rb', line 10

def maybe(&blk)
  do_m(MaybeM, &blk)
end

.present(&blk) ⇒ Object 



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# File 'lib/monadt.rb', line 14

def present(&blk)
  do_m(PresentM, &blk)
end

.reader(&blk) ⇒ Object 



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# File 'lib/monadt.rb', line 31

def reader(&blk)
  do_m(ReaderM, &blk)
end

.reader_state_choice(&blk) ⇒ Object 



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# File 'lib/monadt.rb', line 39

def reader_state_choice(&blk)
  do_m(ReaderStateEitherM, &blk)
end

.run_reader(env, &blk) ⇒ Object 



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# File 'lib/monadt.rb', line 35

def run_reader(env, &blk)
  reader(&blk).(env)
end

.run_reader_state_choice(env, initial_state, &blk) ⇒ Object 



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

def run_reader_state_choice(env, initial_state, &blk)
  reader_state_choice(&blk).(env, initial_state).first
end

.run_state(initial_state, &blk) ⇒ Object 



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

def run_state(initial_state, &blk)
  prc = state(&blk)
  prc.(initial_state).first
end

.state(&blk) ⇒ Object 



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# File 'lib/monadt.rb', line 22

def state(&blk)
  do_m(StateM, &blk)
end