Andrey Breslav
31 lines
509 B
Plaintext
31 lines
509 B
Plaintext
virtual class Builder<E, R> {
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[operator] fun plusAssign(item : E)
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fun result() : R
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}
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virtual class Buildable {
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fun newBuilder<E, R>() : Builder<E, R>
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}
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class List<T> {
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class object Buildable {
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override fun newBuilder<E, R>() : Builder<E, R>
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}
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}
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extension Map<E, T>
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where
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T : Iterable<E>,
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class object T : Buildable<E, T> for T {
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fun map<R>(f : {(E) : R}) : T<R> = {
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val builder = T.newBuilder()
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for (e in this) {
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builder += f(e)
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}
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builder.result()
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}
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} |