forked from Mirror/wren
f5d9443d0a
These lazy iterator producing methods are useful when working with arbitrary sequences and you need to skip or take some number of elements at the start.
29 lines
722 B
Plaintext
29 lines
722 B
Plaintext
class TestSequence is Sequence {
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construct new() {}
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iterate(iterator) {
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if (iterator == null) return 1
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if (iterator == 3) return false
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return iterator + 1
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}
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iteratorValue(iterator) { iterator }
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}
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var test = TestSequence.new().skip(0)
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System.print(test is Sequence) // expect: true
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System.print(test) // expect: instance of SkipSequence
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// Skipping 0 changes nothing
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System.print(test.toList) // expect: [1, 2, 3]
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// Skipping 1 works
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System.print(test.skip(1).toList) // expect: [2, 3]
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// Skipping more than length of sequence produces empty list
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System.print(test.skip(4).isEmpty) // expect: true
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// Skipping less than 0 changes nothing
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System.print(test.skip(-10).toList) // expect: [1, 2, 3]
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