Class new title: Set
	subclassof: Stream
	fields: 'views'
	declare: ''

 t1 
	[array  t1]

 t1 _ t2 
	[position + 1 = t1  [self next_ t2]
	array  t1 _ t2]

add: t1 
	[self next_ t1]

append: t1 |  
	[for t1 from: t1 do
		[self next_ t1]]

asSet

asStream 
	[self viewer]

checkIndex: t1 
	[t1  1 and t1 
 position  [t1]
	user notify: 'illegal index']

copy 
	[self viewer copy]

default 
	[self vector: 8]

delete: t1 | t2  
	[for t2 to: position do
		[array  t2  t1  [self deleteI: t2]].
	false]

deleteI: t1 | t2 t3  
	[t2 _ self  t1.
	for t3 from: t1 to: position - 1 do
		[array  t3 _ array  (t3 + 1)].
	array  position _ nil.
	position _ position - 1.
	t2]

deleteI: t1 to: t2 | t3 t4   
	[t3 _ t2 - t1 + 1.
	for t4 from: t1 to: position - t3 do
		[array  t4 _ array  (t4 + t3)].
	for t4 from: position - t3 + 1 to: position do
		[array  t4 _ nil].
	position _ position - t3]

dotproduct: t1 | t2 t3  
	[t3 _ 0.0.
	self length = t1 length 
		[for t2 to: position do
			[t3 _ t3 + (t1  t2 * (self  t2))].
		t3]
	user notify: 'dot product undefined...sets are not of equal length']

find: t1 | t2  
	[for t2 to: position do
		[array  t2 = t1  [t2]].
	0]

grow 
	[self growby: (10 max: limit / 4)]

growby: t1 | t2 
	[t2 _ Set new of: array to: position.
	self of: (array species new: limit + t1) to: 0.
	t2]

has: t1 
	[(self find: t1) > 0]

initView: t1 
	[t1 of: array to: position]

insert: t1 
	[(self find: t1) = 0  [self next_ t1]]

insertI: t1 value: t2 | t3 t4   
	[t1 > position  [self next_ t2]
	t3 _ array.
	[position = limit 
		[limit _ limit + (10 max: limit / 4).
		array _ array species new: limit.
		for t4 to: t1 - 1 do
			[array  t4 _ t3  t4]]].
	for t4 from: position to: t1 by: 1 do
		[array  t4 + 1 _ t3  t4].
	array  t1 _ t2.
	position _ position + 1]

length [position]

next 
	[user notify: 'no direct reading of a Set']

notViewed: t1 
	[views delete: t1.
	views empty  [views _ nil]]

of: t1 to: t2 
	[array _ t1.
	position _ t2.
	limit _ array length]

pastend_ t1 
	[self append: self grow.
	self next_ t1]

printon: t1 | t2  
	[t1 append: 'a Set: '.
	array is: String  [t1 append: self]
	for t2 from: self do
		[t1 space.
		t1 print: t2]]

product: t1 | t2 t3  
	[t2 _ Set new default.
	self length = t1 length 
		[for t3 to: position do
			[t2 add: t1  t3 * (self  t3)].
		t2]
	user notify: 'product undefined...sets are not of equal length']

species 
	[array species]

string: t1 
	[limit _ t1.
	self of: (String new: limit)]

summation | t1 t2  
	[t2 _ 0.0.
	for t1 to: position do
		[t2 _ t2 + (self  t1)].
	t2]

vector: t1 
	[limit _ t1.
	self of: (Vector new: limit)]

viewRange: t1 to: t2 
	[SetReader new of: array from: t1 to: t2]

viewer 
	[SetReader new of: array from: 1 to: position]

viewer: t1 
	[[views  nil  [views _ Set default]].
	views next_ t1]