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author | Martin Odersky <odersky@gmail.com> | 2015-10-24 17:48:21 +0200 |
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committer | Martin Odersky <odersky@gmail.com> | 2015-10-24 17:48:21 +0200 |
commit | cdcc7e3592386fcfe0f2b9915db78a894ac92536 (patch) | |
tree | 251eeeb55b94f54dbcf96bfe8d33be02f9390ecb | |
parent | 538764f17ee1bb94dbfb2d2fb4241c55af3dc896 (diff) | |
download | dotty-cdcc7e3592386fcfe0f2b9915db78a894ac92536.tar.gz dotty-cdcc7e3592386fcfe0f2b9915db78a894ac92536.tar.bz2 dotty-cdcc7e3592386fcfe0f2b9915db78a894ac92536.zip |
Add fixed version of GenTraversableFactory.
There is still an issue because math uses inner classes named
Ops which shadow each other. Dotty can't handle it, so implicit
search in `range` goes wrong. The new test has been modified
to work around that issue.
-rw-r--r-- | tests/pos/GenTraversableFactory.scala | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/tests/pos/GenTraversableFactory.scala b/tests/pos/GenTraversableFactory.scala new file mode 100644 index 000000000..e5cba4501 --- /dev/null +++ b/tests/pos/GenTraversableFactory.scala @@ -0,0 +1,256 @@ +/* __ *\ +** ________ ___ / / ___ Scala API ** +** / __/ __// _ | / / / _ | (c) 2006-2013, LAMP/EPFL ** +** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ ** +** /____/\___/_/ |_/____/_/ | | ** +** |/ ** +\* */ + + +package scala +package collection +package generic + +import scala.language.higherKinds + +/** A template for companion objects of `Traversable` and subclasses thereof. + * This class provides a set of operations to create `$Coll` objects. + * It is typically inherited by companion objects of subclasses of `Traversable`. + * + * @since 2.8 + * + * @define coll collection + * @define Coll `Traversable` + * @define factoryInfo + * This object provides a set of operations to create `$Coll` values. + * @author Martin Odersky + * @version 2.8 + * @define canBuildFromInfo + * The standard `CanBuildFrom` instance for $Coll objects. + * @see CanBuildFrom + * @define genericCanBuildFromInfo + * The standard `CanBuildFrom` instance for $Coll objects. + * The created value is an instance of class `GenericCanBuildFrom`, + * which forwards calls to create a new builder to the + * `genericBuilder` method of the requesting collection. + * @see CanBuildFrom + * @see GenericCanBuildFrom + */ +abstract class GenTraversableFactory[CC[X] <: GenTraversable[X] with GenericTraversableTemplate[X, CC]] +extends GenericCompanion[CC] { + + private[this] val ReusableCBFInstance: GenericCanBuildFrom[Nothing] = new GenericCanBuildFrom[Nothing] { + override def apply() = newBuilder[Nothing] + } + def ReusableCBF: GenericCanBuildFrom[Nothing] = ReusableCBFInstance + + /** A generic implementation of the `CanBuildFrom` trait, which forwards + * all calls to `apply(from)` to the `genericBuilder` method of + * $coll `from`, and which forwards all calls of `apply()` to the + * `newBuilder` method of this factory. + */ + class GenericCanBuildFrom[A] extends CanBuildFrom[CC[_], A, CC[A]] { + /** Creates a new builder on request of a collection. + * @param from the collection requesting the builder to be created. + * @return the result of invoking the `genericBuilder` method on `from`. + */ + def apply(from: Coll) = from.genericBuilder[A] + + /** Creates a new builder from scratch + * @return the result of invoking the `newBuilder` method of this factory. + */ + def apply() = newBuilder[A] + } + + /** Concatenates all argument collections into a single $coll. + * + * @param xss the collections that are to be concatenated. + * @return the concatenation of all the collections. + */ + def concat[A](xss: Traversable[A]*): CC[A] = { + val b = newBuilder[A] + // At present we're using IndexedSeq as a proxy for "has a cheap size method". + if (xss forall (_.isInstanceOf[IndexedSeq[_]])) + b.sizeHint(xss.map(_.size).sum) + + for (xs <- xss.seq) b ++= xs + b.result() + } + + /** Produces a $coll containing the results of some element computation a number of times. + * @param n the number of elements contained in the $coll. + * @param elem the element computation + * @return A $coll that contains the results of `n` evaluations of `elem`. + */ + def fill[A](n: Int)(elem: => A): CC[A] = { + val b = newBuilder[A] + b.sizeHint(n) + var i = 0 + while (i < n) { + b += elem + i += 1 + } + b.result() + } + + /** Produces a two-dimensional $coll containing the results of some element computation a number of times. + * @param n1 the number of elements in the 1st dimension + * @param n2 the number of elements in the 2nd dimension + * @param elem the element computation + * @return A $coll that contains the results of `n1 x n2` evaluations of `elem`. + */ + def fill[A](n1: Int, n2: Int)(elem: => A): CC[CC[A]] = + tabulate(n1)(_ => fill(n2)(elem)) + + /** Produces a three-dimensional $coll containing the results of some element computation a number of times. + * @param n1 the number of elements in the 1st dimension + * @param n2 the number of elements in the 2nd dimension + * @param n3 the number of elements in the 3nd dimension + * @param elem the element computation + * @return A $coll that contains the results of `n1 x n2 x n3` evaluations of `elem`. + */ + def fill[A](n1: Int, n2: Int, n3: Int)(elem: => A): CC[CC[CC[A]]] = + tabulate(n1)(_ => fill(n2, n3)(elem)) + + /** Produces a four-dimensional $coll containing the results of some element computation a number of times. + * @param n1 the number of elements in the 1st dimension + * @param n2 the number of elements in the 2nd dimension + * @param n3 the number of elements in the 3nd dimension + * @param n4 the number of elements in the 4th dimension + * @param elem the element computation + * @return A $coll that contains the results of `n1 x n2 x n3 x n4` evaluations of `elem`. + */ + def fill[A](n1: Int, n2: Int, n3: Int, n4: Int)(elem: => A): CC[CC[CC[CC[A]]]] = + tabulate(n1)(_ => fill(n2, n3, n4)(elem)) + + /** Produces a five-dimensional $coll containing the results of some element computation a number of times. + * @param n1 the number of elements in the 1st dimension + * @param n2 the number of elements in the 2nd dimension + * @param n3 the number of elements in the 3nd dimension + * @param n4 the number of elements in the 4th dimension + * @param n5 the number of elements in the 5th dimension + * @param elem the element computation + * @return A $coll that contains the results of `n1 x n2 x n3 x n4 x n5` evaluations of `elem`. + */ + def fill[A](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(elem: => A): CC[CC[CC[CC[CC[A]]]]] = + tabulate(n1)(_ => fill(n2, n3, n4, n5)(elem)) + + /** Produces a $coll containing values of a given function over a range of integer values starting from 0. + * @param n The number of elements in the $coll + * @param f The function computing element values + * @return A $coll consisting of elements `f(0), ..., f(n -1)` + */ + def tabulate[A](n: Int)(f: Int => A): CC[A] = { + val b = newBuilder[A] + b.sizeHint(n) + var i = 0 + while (i < n) { + b += f(i) + i += 1 + } + b.result() + } + + /** Produces a two-dimensional $coll containing values of a given function over ranges of integer values starting from 0. + * @param n1 the number of elements in the 1st dimension + * @param n2 the number of elements in the 2nd dimension + * @param f The function computing element values + * @return A $coll consisting of elements `f(i1, i2)` + * for `0 <= i1 < n1` and `0 <= i2 < n2`. + */ + def tabulate[A](n1: Int, n2: Int)(f: (Int, Int) => A): CC[CC[A]] = + tabulate(n1)(i1 => tabulate(n2)(f(i1, _))) + + /** Produces a three-dimensional $coll containing values of a given function over ranges of integer values starting from 0. + * @param n1 the number of elements in the 1st dimension + * @param n2 the number of elements in the 2nd dimension + * @param n3 the number of elements in the 3nd dimension + * @param f The function computing element values + * @return A $coll consisting of elements `f(i1, i2, i3)` + * for `0 <= i1 < n1`, `0 <= i2 < n2`, and `0 <= i3 < n3`. + */ + def tabulate[A](n1: Int, n2: Int, n3: Int)(f: (Int, Int, Int) => A): CC[CC[CC[A]]] = + tabulate(n1)(i1 => tabulate(n2, n3)(f(i1, _, _))) + + /** Produces a four-dimensional $coll containing values of a given function over ranges of integer values starting from 0. + * @param n1 the number of elements in the 1st dimension + * @param n2 the number of elements in the 2nd dimension + * @param n3 the number of elements in the 3nd dimension + * @param n4 the number of elements in the 4th dimension + * @param f The function computing element values + * @return A $coll consisting of elements `f(i1, i2, i3, i4)` + * for `0 <= i1 < n1`, `0 <= i2 < n2`, `0 <= i3 < n3`, and `0 <= i4 < n4`. + */ + def tabulate[A](n1: Int, n2: Int, n3: Int, n4: Int)(f: (Int, Int, Int, Int) => A): CC[CC[CC[CC[A]]]] = + tabulate(n1)(i1 => tabulate(n2, n3, n4)(f(i1, _, _, _))) + + /** Produces a five-dimensional $coll containing values of a given function over ranges of integer values starting from 0. + * @param n1 the number of elements in the 1st dimension + * @param n2 the number of elements in the 2nd dimension + * @param n3 the number of elements in the 3nd dimension + * @param n4 the number of elements in the 4th dimension + * @param n5 the number of elements in the 5th dimension + * @param f The function computing element values + * @return A $coll consisting of elements `f(i1, i2, i3, i4, i5)` + * for `0 <= i1 < n1`, `0 <= i2 < n2`, `0 <= i3 < n3`, `0 <= i4 < n4`, and `0 <= i5 < n5`. + */ + def tabulate[A](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(f: (Int, Int, Int, Int, Int) => A): CC[CC[CC[CC[CC[A]]]]] = + tabulate(n1)(i1 => tabulate(n2, n3, n4, n5)(f(i1, _, _, _, _))) + + /** Produces a $coll containing a sequence of increasing of integers. + * + * @param start the first element of the $coll + * @param end the end value of the $coll (the first value NOT contained) + * @return a $coll with values `start, start + 1, ..., end - 1` + */ + def range[T: Integral](start: T, end: T): CC[T] = range(start, end, implicitly[Integral[T]].one) + + /** Produces a $coll containing equally spaced values in some integer interval. + * @param start the start value of the $coll + * @param end the end value of the $coll (the first value NOT contained) + * @param step the difference between successive elements of the $coll (must be positive or negative) + * @return a $coll with values `start, start + step, ...` up to, but excluding `end` + */ + def range[T: Integral](start: T, end: T, step: T): CC[T] = { + val num = implicitly[Integral[T]] + import num._ + + if (step == zero) throw new IllegalArgumentException("zero step") + val b = newBuilder[T] + b sizeHint immutable.NumericRange.count(start, end, step, isInclusive = false) + var i = start + + { + val ord: Ordering[T] = num + implicit val ops: T => ord.Ops = ord.mkOrderingOps + while (if (step < zero) end < i else i < end) { + b += i + i += step + }} + b.result() + } + + /** Produces a $coll containing repeated applications of a function to a start value. + * + * @param start the start value of the $coll + * @param len the number of elements contained inthe $coll + * @param f the function that's repeatedly applied + * @return a $coll with `len` values in the sequence `start, f(start), f(f(start)), ...` + */ + def iterate[A](start: A, len: Int)(f: A => A): CC[A] = { + val b = newBuilder[A] + if (len > 0) { + b.sizeHint(len) + var acc = start + var i = 1 + b += acc + + while (i < len) { + acc = f(acc) + i += 1 + b += acc + } + } + b.result() + } +} |