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Diffstat (limited to 'examples/scala-js/library/src/main/scala/scala/scalajs/js/UndefOr.scala')
| -rw-r--r-- | examples/scala-js/library/src/main/scala/scala/scalajs/js/UndefOr.scala | 254 |
1 files changed, 0 insertions, 254 deletions
diff --git a/examples/scala-js/library/src/main/scala/scala/scalajs/js/UndefOr.scala b/examples/scala-js/library/src/main/scala/scala/scalajs/js/UndefOr.scala deleted file mode 100644 index b356e3a..0000000 --- a/examples/scala-js/library/src/main/scala/scala/scalajs/js/UndefOr.scala +++ /dev/null @@ -1,254 +0,0 @@ -/* __ *\ -** ________ ___ / / ___ __ ____ Scala.js API ** -** / __/ __// _ | / / / _ | __ / // __/ (c) 2013, LAMP/EPFL ** -** __\ \/ /__/ __ |/ /__/ __ |/_// /_\ \ http://scala-lang.org/ ** -** /____/\___/_/ |_/____/_/ | |__/ /____/ ** -** |/____/ ** -\* */ - - -package scala.scalajs.js - -import scala.language.implicitConversions - -/** Value of type A or the JS undefined value. - * In a type system with union types, this would really be - * `A | js.prim.Undefined`. Since Scala does not have union types, but this - * particular union is crucial to many interoperability scenarios, it is - * provided as this trait. - * - * An API similar to that of [[scala.Option]] is provided through the - * [[UndefOrOps]] implicit class, with the understanding that `undefined` is - * the None value. - */ -@scala.scalajs.js.annotation.RawJSType // Don't do this at home! -sealed trait UndefOr[+A] - -object UndefOr { - implicit def any2undefOrA[A](value: A): UndefOr[A] = - value.asInstanceOf[UndefOr[A]] - - implicit def undef2undefOr(value: prim.Undefined): UndefOr[Nothing] = - value.asInstanceOf[UndefOr[Nothing]] - - implicit def undefOr2ops[A](value: UndefOr[A]): UndefOrOps[A] = - new UndefOrOps(value) - - implicit def undefOr2jsAny[A](value: UndefOr[A])(implicit ev: A => Any): Any = - value.map(ev).asInstanceOf[Any] -} - -final class UndefOrOps[A](val self: UndefOr[A]) extends AnyVal { - import UndefOrOps._ - - /** Returns true if the option is `undefined`, false otherwise. - */ - @inline final def isEmpty: Boolean = isUndefined(self) - - /** Returns true if the option is not `undefined`, false otherwise. - */ - @inline final def isDefined: Boolean = !isEmpty - - /** Returns the option's value. - * @note The option must be nonEmpty. - * @throws Predef.NoSuchElementException if the option is empty. - */ - @inline final def get: A = - if (isEmpty) throw new NoSuchElementException("undefined.get") - else self.asInstanceOf[A] - - @inline final private def forceGet: A = self.asInstanceOf[A] - - /** Returns the option's value if the option is nonempty, otherwise - * return the result of evaluating `default`. - * - * @param default the default expression. - */ - @inline final def getOrElse[B >: A](default: => B): B = - if (isEmpty) default else this.forceGet - - /** Returns the option's value if it is nonempty, - * or `null` if it is empty. - * Although the use of null is discouraged, code written to use - * $option must often interface with code that expects and returns nulls. - * @example {{{ - * val initalText: Option[String] = getInitialText - * val textField = new JComponent(initalText.orNull,20) - * }}} - */ - @inline final def orNull[A1 >: A](implicit ev: Null <:< A1): A1 = - this getOrElse ev(null) - - /** Returns a $some containing the result of applying $f to this $option's - * value if this $option is nonempty. - * Otherwise return $none. - * - * @note This is similar to `flatMap` except here, - * $f does not need to wrap its result in an $option. - * - * @param f the function to apply - * @see flatMap - * @see foreach - */ - @inline final def map[B](f: A => B): UndefOr[B] = - if (isEmpty) undefined else f(this.forceGet) - - /** Returns the result of applying $f to this $option's - * value if the $option is nonempty. Otherwise, evaluates - * expression `ifEmpty`. - * - * @note This is equivalent to `$option map f getOrElse ifEmpty`. - * - * @param ifEmpty the expression to evaluate if empty. - * @param f the function to apply if nonempty. - */ - @inline final def fold[B](ifEmpty: => B)(f: A => B): B = - if (isEmpty) ifEmpty else f(this.forceGet) - - /** Returns the result of applying $f to this $option's value if - * this $option is nonempty. - * Returns $none if this $option is empty. - * Slightly different from `map` in that $f is expected to - * return an $option (which could be $none). - * - * @param f the function to apply - * @see map - * @see foreach - */ - @inline final def flatMap[B](f: A => UndefOr[B]): UndefOr[B] = - if (isEmpty) undefined else f(this.forceGet) - - def flatten[B](implicit ev: A <:< UndefOr[B]): UndefOr[B] = - if (isEmpty) undefined else ev(this.forceGet) - - /** Returns this $option if it is nonempty '''and''' applying the predicate $p to - * this $option's value returns true. Otherwise, return $none. - * - * @param p the predicate used for testing. - */ - @inline final def filter(p: A => Boolean): UndefOr[A] = - if (isEmpty || p(this.forceGet)) self else undefined - - /** Returns this $option if it is nonempty '''and''' applying the predicate $p to - * this $option's value returns false. Otherwise, return $none. - * - * @param p the predicate used for testing. - */ - @inline final def filterNot(p: A => Boolean): UndefOr[A] = - if (isEmpty || !p(this.forceGet)) self else undefined - - /** Returns false if the option is $none, true otherwise. - * @note Implemented here to avoid the implicit conversion to Iterable. - */ - final def nonEmpty = isDefined - - /** Necessary to keep $option from being implicitly converted to - * [[scala.collection.Iterable]] in `for` comprehensions. - */ - @inline final def withFilter(p: A => Boolean): WithFilter[A] = - new WithFilter(self, p) - - /** Returns true if this option is nonempty '''and''' the predicate - * $p returns true when applied to this $option's value. - * Otherwise, returns false. - * - * @param p the predicate to test - */ - @inline final def exists(p: A => Boolean): Boolean = - !isEmpty && p(this.forceGet) - - /** Returns true if this option is empty '''or''' the predicate - * $p returns true when applied to this $option's value. - * - * @param p the predicate to test - */ - @inline final def forall(p: A => Boolean): Boolean = - isEmpty || p(this.forceGet) - - /** Apply the given procedure $f to the option's value, - * if it is nonempty. Otherwise, do nothing. - * - * @param f the procedure to apply. - * @see map - * @see flatMap - */ - @inline final def foreach[U](f: A => U): Unit = - if (!isEmpty) f(this.forceGet) - - /** Returns a $some containing the result of - * applying `pf` to this $option's contained - * value, '''if''' this option is - * nonempty '''and''' `pf` is defined for that value. - * Returns $none otherwise. - * - * @param pf the partial function. - * @return the result of applying `pf` to this $option's - * value (if possible), or $none. - */ - @inline final def collect[B](pf: PartialFunction[A, B]): UndefOr[B] = - if (isEmpty) undefined - else pf.applyOrElse(this.forceGet, (_: A) => undefined).asInstanceOf[UndefOr[B]] - - /** Returns this $option if it is nonempty, - * otherwise return the result of evaluating `alternative`. - * @param alternative the alternative expression. - */ - @inline final def orElse[B >: A](alternative: => UndefOr[B]): UndefOr[B] = - if (isEmpty) alternative else self - - /** Returns a singleton iterator returning the $option's value - * if it is nonempty, or an empty iterator if the option is empty. - */ - def iterator: Iterator[A] = - if (isEmpty) scala.collection.Iterator.empty - else scala.collection.Iterator.single(this.forceGet) - - /** Returns a singleton list containing the $option's value - * if it is nonempty, or the empty list if the $option is empty. - */ - def toList: List[A] = - if (isEmpty) Nil else this.forceGet :: Nil - - /** Returns a [[scala.util.Left]] containing the given - * argument `left` if this $option is empty, or - * a [[scala.util.Right]] containing this $option's value if - * this is nonempty. - * - * @param left the expression to evaluate and return if this is empty - * @see toLeft - */ - @inline final def toRight[X](left: => X): Either[X, A] = - if (isEmpty) Left(left) else Right(this.forceGet) - - /** Returns a [[scala.util.Right]] containing the given - * argument `right` if this is empty, or - * a [[scala.util.Left]] containing this $option's value - * if this $option is nonempty. - * - * @param right the expression to evaluate and return if this is empty - * @see toRight - */ - @inline final def toLeft[X](right: => X): Either[A, X] = - if (isEmpty) Right(right) else Left(this.forceGet) - - /** Returns a [[scala.Some]] containing this $options's value - * if this $option is nonempty, [[scala.None]] otherwise. - */ - @inline final def toOption: Option[A] = - if (isEmpty) None else Some(this.forceGet) -} - -object UndefOrOps { - - /** We need a whole WithFilter class to honor the "doesn't create a new - * collection" contract even though it seems unlikely to matter much in a - * collection with max size 1. - */ - class WithFilter[A](self: UndefOr[A], p: A => Boolean) { - def map[B](f: A => B): UndefOr[B] = self filter p map f - def flatMap[B](f: A => UndefOr[B]): UndefOr[B] = self filter p flatMap f - def foreach[U](f: A => U): Unit = self filter p foreach f - def withFilter(q: A => Boolean): WithFilter[A] = - new WithFilter[A](self, x => p(x) && q(x)) - } -} |