Alex Tkachman
87 lines
2.3 KiB
Kotlin
87 lines
2.3 KiB
Kotlin
package std.util
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import java.util.*
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/** Returns the size of the collection */
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val Collection<*>.size : Int
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get() = size()
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/** Returns true if this collection is empty */
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val Collection<*>.empty : Boolean
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get() = isEmpty()
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/** Returns a new ArrayList with a variable number of initial elements */
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inline fun arrayList<T>(vararg values: T) : ArrayList<T> = values.to(ArrayList<T>(values.size))
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/** Returns a new LinkedList with a variable number of initial elements */
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inline fun linkedList<T>(vararg values: T) : LinkedList<T> = values.to(LinkedList<T>())
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/** Returns a new HashSet with a variable number of initial elements */
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inline fun hashSet<T>(vararg values: T) : HashSet<T> = values.to(HashSet<T>(values.size))
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val Collection<*>.indices : IntRange
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get() = 0..size-1
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inline fun <T> java.util.Collection<T>.toArray() : Array<T> {
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val answer = Array<T>(this.size)
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var idx = 0
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for (elem in this)
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answer[idx++] = elem
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return answer as Array<T>
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}
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/** TODO these functions don't work when they generate the Array<T> versions when they are in JavaIterables */
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inline fun <in T: java.lang.Comparable<T>> java.lang.Iterable<T>.toSortedList() : List<T> = toList().sort()
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inline fun <in T: java.lang.Comparable<T>> java.lang.Iterable<T>.toSortedList(comparator: java.util.Comparator<T>) : List<T> = toList().sort(comparator)
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// List APIs
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inline fun <in T: java.lang.Comparable<T>> List<T>.sort() : List<T> {
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Collections.sort(this)
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return this
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}
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inline fun <in T: java.lang.Comparable<T>> List<T>.sort(comparator: java.util.Comparator<T>) : List<T> {
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Collections.sort(this, comparator)
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return this
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}
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/**
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TODO figure out necessary variance/generics ninja stuff... :)
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inline fun <in T> List<T>.sort(transform: fun(T) : java.lang.Comparable<*>) : List<T> {
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val comparator = java.util.Comparator<T>() {
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fun compare(o1: T, o2: T): Int {
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val v1 = transform(o1)
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val v2 = transform(o2)
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if (v1 == v2) {
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return 0
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} else {
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return v1.compareTo(v2)
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}
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}
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}
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answer.sort(comparator)
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}
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*/
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val <T> List<T>.head : T?
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get() = this.get(0)
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val <T> List<T>.first : T?
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get() = this.head
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val <T> List<T>.tail : T?
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get() {
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val s = this.size
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return if (s > 0) this.get(s - 1) else null
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}
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val <T> List<T>.last : T?
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get() = this.tail
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