diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Typers.scala | 2 | ||||
| -rw-r--r-- | src/library/scala/util/Try.scala | 29 |
2 files changed, 30 insertions, 1 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index 8a3ceb3aca..1004777f23 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -4715,7 +4715,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper UnstableTreeError(qualTyped) ) val tree1 = name match { - case nme.withFilter => tryWithFilterAndFilter(tree, qualStableOrError) + case nme.withFilter if !settings.future => tryWithFilterAndFilter(tree, qualStableOrError) case _ => typedSelect(tree, qualStableOrError, name) } def sym = tree1.symbol diff --git a/src/library/scala/util/Try.scala b/src/library/scala/util/Try.scala index 89db57a55e..b0cf122f2a 100644 --- a/src/library/scala/util/Try.scala +++ b/src/library/scala/util/Try.scala @@ -111,6 +111,35 @@ sealed abstract class Try[+T] { */ def filter(p: T => Boolean): Try[T] + /** Creates a non-strict filter, which eventually converts this to a `Failure` + * if the predicate is not satisfied. + * + * Note: unlike filter, withFilter does not create a new Try. + * Instead, it restricts the domain of subsequent + * `map`, `flatMap`, `foreach`, and `withFilter` operations. + * + * As Try is a one-element collection, this may be a bit overkill, + * but it's consistent with withFilter on Option and the other collections. + * + * @param p the predicate used to test elements. + * @return an object of class `WithFilter`, which supports + * `map`, `flatMap`, `foreach`, and `withFilter` operations. + * All these operations apply to those elements of this Try + * which satisfy the predicate `p`. + */ + @inline final def withFilter(p: T => Boolean): WithFilter = new WithFilter(p) + + /** 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(p: T => Boolean) { + def map[U](f: T => U): Try[U] = Try.this filter p map f + def flatMap[U](f: T => Try[U]): Try[U] = Try.this filter p flatMap f + def foreach[U](f: T => U): Unit = Try.this filter p foreach f + def withFilter(q: T => Boolean): WithFilter = new WithFilter(x => p(x) && q(x)) + } + /** * Applies the given function `f` if this is a `Failure`, otherwise returns this if this is a `Success`. * This is like `flatMap` for the exception. |