[331] | 1 | assert("Enumerator::Lazy") do
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[270] | 2 | a = [1, 2]
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[331] | 3 | assert_equal Enumerator::Lazy, a.lazy.class
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[270] | 4 | end
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| 5 |
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[331] | 6 | assert("Enumerator::Lazy laziness") do
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[270] | 7 | a = Object.new
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| 8 | def a.each
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| 9 | return to_enum :each unless block_given?
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| 10 | self.b << 10
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| 11 | yield 1
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| 12 | self.b << 20
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| 13 | yield 2
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| 14 | self.b << 30
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| 15 | yield 3
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| 16 | self.b << 40
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| 17 | yield 4
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| 18 | self.b << 50
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| 19 | yield 5
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| 20 | end
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| 21 | def a.b(b=nil)
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| 22 | @b = b if b
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| 23 | @b
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| 24 | end
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| 25 |
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| 26 | a.b([])
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| 27 | assert_equal [1,2], a.each.lazy.take(2).force
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| 28 | assert_equal [10,20], a.b
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| 29 |
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| 30 | a.b([])
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| 31 | assert_equal [2,4], a.each.lazy.select{|x|x%2==0}.take(2).force
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| 32 | assert_equal [10,20,30,40], a.b
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| 33 |
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| 34 | a.b([])
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| 35 | assert_equal [1], a.each.lazy.take_while{|x|x<2}.take(1).force
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| 36 | assert_equal [10], a.b
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| 37 |
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| 38 | a.b([])
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| 39 | assert_equal [1], a.each.lazy.take_while{|x|x<2}.take(4).force
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| 40 | assert_equal [10,20], a.b
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| 41 | end
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| 42 |
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[439] | 43 | assert("Enumerator::Lazy#to_enum") do
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[331] | 44 | lazy_enum = (0..Float::INFINITY).lazy.to_enum(:each_slice, 2)
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| 45 | assert_kind_of Enumerator::Lazy, lazy_enum
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| 46 | assert_equal [0*1, 2*3, 4*5, 6*7], lazy_enum.map { |a| a.first * a.last }.first(4)
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| 47 | end
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| 48 |
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| 49 | assert("Enumerator::Lazy#zip with cycle") do
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[270] | 50 | e1 = [1, 2, 3].cycle
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| 51 | e2 = [:a, :b].cycle
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| 52 | assert_equal [[1,:a],[2,:b],[3,:a]], e1.lazy.zip(e2).first(3)
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| 53 | end
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