Class new title: Interval
	subclassof: Array
	fields: 'start stop step length'
	declare: ''

 t1 
	[[t1 is: Integer 
		[t1 < 1  [nil]
		t1 > length  [nil]
		start + (step * (t1 - 1))]].
	super  t1]

 t1 _ t2 
	[user notify: 'Intervals are not for writing into']

= t1 
	[start = t1 start and (stop = t1 stop and length = t1 length)]

cansubscript: t1 
	[length 
 0 or ((start cansubscript: t1) and (length - 1 * step + start cansubscript: t1))]

from: t1 to: t2 by: t3 
	[start _ t1.
	stop _ t2.
	step _ t3.
	length _ 1 + (stop - start / step).
	step < 0 
		[start < stop  [length _ 0]]
	stop < start  [length _ 0]]

isIntervalBy1 
	[step = 1]

length [length]

random 
	[step _ (13849 + (27181 * step)) asInt16.
	(start + (length asFloat * (32768.0 + step) / 65536.0)) asSmall]

randomInit 
	[self randomInit: mem  280]

randomInit: t1 
	[step _ t1.
	start is: Float  [length _ stop - start]]

start [start]

stop [stop]