mirror of https://github.com/sbt/sbt.git
49 lines
1.4 KiB
Scala
49 lines
1.4 KiB
Scala
/* sbt -- Simple Build Tool
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* Copyright 2010 Mark Harrah
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*/
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package sbt
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import Types._
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trait RMap[K[_], V[_]]
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{
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def apply[T](k: K[T]): V[T]
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def get[T](k: K[T]): Option[V[T]]
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def contains[T](k: K[T]): Boolean
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}
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trait PMap[K[_], V[_]] extends (K ~> V) with RMap[K,V]
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{
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def update[T](k: K[T], v: V[T]): Unit
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def remove[T](k: K[T]): Option[V[T]]
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def getOrUpdate[T](k: K[T], make: => V[T]): V[T]
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}
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object PMap
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{
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implicit def toFunction[K[_], V[_]](map: PMap[K,V]): K[_] => V[_] = k => map(k)
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}
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abstract class AbstractPMap[K[_], V[_]] extends PMap[K,V]
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{
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def apply[T](k: K[T]): V[T] = get(k).get
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def contains[T](k: K[T]): Boolean = get(k).isDefined
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}
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import collection.mutable.Map
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/**
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* Only suitable for K that is invariant in its type parameter.
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* Option and List keys are not suitable, for example,
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* because None <:< Option[String] and None <: Option[Int].
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*/
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class DelegatingPMap[K[_], V[_]](backing: Map[K[_], V[_]]) extends AbstractPMap[K,V]
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{
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def get[T](k: K[T]): Option[V[T]] = cast[T]( backing.get(k) )
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def update[T](k: K[T], v: V[T]) { backing(k) = v }
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def remove[T](k: K[T]) = cast( backing.remove(k) )
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def getOrUpdate[T](k: K[T], make: => V[T]) = cast[T]( backing.getOrElseUpdate(k, make) )
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private[this] def cast[T](v: V[_]): V[T] = v.asInstanceOf[V[T]]
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private[this] def cast[T](o: Option[V[_]]): Option[V[T]] = o map cast[T]
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override def toString = backing.toString
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} |