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|
# Integer : shrink to zero
class Integer
def shrink
if self > 8
self / 2
elsif self > 0
self - 1
elsif self < -8
(self + 1) / 2
elsif self < 0
self + 1
else
0
end
end
def retry?
false
end
def shrinkable?
self != 0
end
end
# String : shrink to ""
class String
def shrink
shrunk = dup
unless empty?
idx = Random.rand(size)
shrunk[idx] = ''
end
shrunk
end
def retry?
false
end
def shrinkable?
self != ''
end
end
# Array where elements can be shrunk but not removed
class Tuple
def initialize(a)
@array = a
@position = a.size - 1
end
def [](i)
@array[i]
end
def []=(i, value)
@array[i] = value
end
def length
@array.length
end
def size
length
end
def to_s
@array.to_s.insert(1, 'T ')
end
def inspect
to_s
end
def each(&block)
@array.each(&block)
end
attr_reader :array
def shrink
shrunk = @array.dup
while @position >= 0
e = @array.at(@position)
break if e.respond_to?(:shrinkable?) && e.shrinkable?
@position -= 1
end
if @position >= 0
shrunk[@position] = e.shrink
@position -= 1
end
Tuple.new(shrunk)
end
def retry?
@position >= 0
end
def shrinkable?
@array.any? { |e| e.respond_to?(:shrinkable?) && e.shrinkable? }
end
end
# Array where the elements that can't be shrunk are removed
class Deflating
def initialize(a)
@array = a
@position = a.size - 1
end
def [](i)
@array[i]
end
def []=(i, value)
@array[i] = value
end
def length
@array.length
end
def size
length
end
def to_s
@array.to_s.insert(1, 'D ')
end
def inspect
to_s
end
def each(&block)
@array.each(&block)
end
attr_reader :array
def shrink
shrunk = @array.dup
if @position >= 0
e = @array.at(@position)
if e.respond_to?(:shrinkable?) && e.shrinkable?
shrunk[@position] = e.shrink
else
shrunk.delete_at(@position)
end
@position -= 1
end
Deflating.new(shrunk)
end
def retry?
@position >= 0
end
def shrinkable?
!@array.empty?
end
end
class Hash
def shrink
if any? { |_, v| v.respond_to?(:shrinkable?) && v.shrinkable? }
key, = detect { |_, v| v.respond_to?(:shrinkable?) && v.shrinkable? }
clone = dup
clone[key] = clone[key].shrink
clone
elsif !empty?
key = keys.first
h2 = dup
h2.delete(key)
h2
else
self
end
end
def shrinkable?
any? { |_, v| v.respond_to?(:shrinkable?) && v.shrinkable? } ||
!empty?
end
def retry?
false
end
end
|
