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bolshakov/list_compare.rb

Last active November 15, 2019 19:18
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list_compare.rb
def <=>(other)
head.match do |lm|
lm.none do
other.head.match do |rm|
rm.some { -1 }
rm.none { 0 }
end
end
lm.some do |left_head|
other.head.match do |rm|
rm.none { +1 }
rm.some do |right_head|
(left_head <=> right_head).yield_self do |comparison|
if comparison == 0
tail <=> other.tail
else
comparison
end
end
end
end
end
end
end
Raw
list_compare_while.rb
def <=>(other)
left = self
right = other
until left.empty? || right.empty?
comparison = left.head! <=> right.head!
if comparison == 0
left = left.tail
right = right.tail
else
return comparison
end
end
case [left.empty?, right.empty?]
when [true, true] then 0
when [true, false] then -1
when [false, true] then +1
end
end
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