Class Semaphore Object count processList
Methods Semaphore
	new
		count <- 0.
		processList <- List new

]
Methods Semaphore

	set: aNumber
		count <- aNumber

]
Methods Semaphore

	wait		| process |
		(count = 0)
			ifTrue: [ scheduler critical:
					[ process <- scheduler currentProcess.
					  processList add: process.
					  scheduler removeProcess: process].
				  scheduler yield ]
			ifFalse: [ count <- count - 1]

]
Methods Semaphore

	critical: aBlock
		self wait.
		aBlock value.
		self signal

]
Methods Semaphore

	signal
		(processList size = 0)
			ifTrue: [ count <- count + 1]
			ifFalse: [ scheduler critical:
				[ processList first resume.
					processList removeFirst ]]

]