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Added methods and tests: tails, inits, filter, filterNot, partitionMap.
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c committed Jan 16, 2025
1 parent a9c8189 commit 30a7327
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12 changes: 6 additions & 6 deletions docs/FeatureGrid.md
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@@ -1,4 +1,4 @@
<s>ArrayOps Features</s>:<br />
<b>ArrayOps Features</b>:<br />
<table style="">
<tr>
<td>Method Signature</td>
Expand Down Expand Up @@ -190,7 +190,7 @@ def tails: Iterator[Array[T]]
</td>
<td>✓</td>
<td>✓</td>
<td>❌</td>
<td>✓</td>
</tr>
<tr>
<td>
Expand All @@ -201,7 +201,7 @@ def inits: Iterator[Array[T]]
</td>
<td>✓</td>
<td>✓</td>
<td>❌</td>
<td>✓</td>
</tr>
<tr>
<td>
Expand Down Expand Up @@ -348,7 +348,7 @@ def partitionMap[A1: ClassTag, A2: ClassTag](
</td>
<td>✓</td>
<td>✓</td>
<td>❌</td>
<td>✓</td>
</tr>
<tr>
<td>
Expand Down Expand Up @@ -383,7 +383,7 @@ def filter(p: T => Boolean): Array[T]
</td>
<td>✓</td>
<td>✓</td>
<td>❌</td>
<td>✓</td>
</tr>
<tr>
<td>
Expand All @@ -394,7 +394,7 @@ def filterNot(p: T => Boolean): Array[T]
</td>
<td>✓</td>
<td>✓</td>
<td>❌</td>
<td>✓</td>
</tr>
<tr>
<td>
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196 changes: 158 additions & 38 deletions narr/js/src/main/scala/narr/native/Extensions.scala
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Expand Up @@ -289,6 +289,47 @@ object Extensions {
/** The initial part of the NArray without its last element. */
inline def init: NArray[T] = slice(0, a.length - 1)


/** Iterates over the tails of this array.
*
* The first value will be this array and the final one will be an empty
* array, with the intervening values the results of successive applications
* of `tail`.
*
* @return an iterator over all the tails of this array
*/
def tails: scala.collection.Iterator[NArray[T]] = new Iterator[NArray[T]] {
var i = 0
override def hasNext: Boolean = i < a.length + 1
override def next(): NArray[T] = {
val out = if (hasNext) {
a.slice(i)
} else throw new NoSuchElementException("next on empty iterator")
i = i + 1
out
}
}

/** Iterates over the inits of this array.
*
* The first value will be this array and the final one will be an empty
* array, with the intervening values the results of successive applications
* of `init`.
*
* @return an iterator over all the inits of this array
*/
def inits: scala.collection.Iterator[NArray[T]] = new Iterator[NArray[T]] {
var i = a.length
override def hasNext: Boolean = i > -1
override def next(): NArray[T] = {
val out = if (hasNext) {
a.slice(0, i)
} else throw new NoSuchElementException("next on empty iterator")
i = i - 1
out
}
}

/** An NArray containing the first `n` elements of this NArray. */
inline def take(n: Int): NArray[T] = slice(0, n)

Expand Down Expand Up @@ -341,7 +382,6 @@ object Extensions {
}
}


/** Returns a new array with the elements in reversed order. */
def reverse: NArray[T] = {
val len = a.length
Expand Down Expand Up @@ -378,6 +418,35 @@ object Extensions {
}
}

/** Selects all elements of this array which satisfy a predicate.
*
* @param p
* the predicate used to test elements.
* @return
* a new array consisting of all elements of this array that satisfy the
* given predicate `p`.
*/
def filter(p: T => Boolean)(using ClassTag[T]): NArray[T] = {
val b = NArrayBuilder[T]()
var i = 0; while (i < a.length) {
val x = a(i)
if (p(x)) b.addOne(x)
i = i + 1
}
b.result
}

/** Selects all elements of this array which do not satisfy a predicate.
*
* @param pred
* the predicate used to test elements.
* @return
* a new array consisting of all elements of this array that do not
* satisfy the given predicate `pred`.
*/
def filterNot(p: T => Boolean)(using ClassTag[T]): NArray[T] = filter(x => !p(x))


def grouped(groupSize: Int): Iterator[NArray[T]] = new scala.collection.AbstractIterator[NArray[T]] {
private[this] var i = 0

Expand Down Expand Up @@ -418,7 +487,7 @@ object Extensions {
def splitAt(n: Int): (NArray[T], NArray[T]) = (take(n), drop(n))

/** A pair of, first, all elements that satisfy predicate `p` and, second, all elements that do not. */
def partition(p: T => Boolean)(using ClassTag[T], ClassTag[NArray[T]]): (NArray[T], NArray[T]) = {
def partition(p: T => Boolean)(using ClassTag[T]): (NArray[T], NArray[T]) = {
val nab1 = NArrayBuilder[T]()
val nab2 = NArrayBuilder[T]()

Expand All @@ -430,6 +499,48 @@ object Extensions {
(nab1.result, nab2.result)
}


/** Applies a function `f` to each element of the array and returns a pair of
* arrays: the first one made of those values returned by `f` that were
* wrapped in [[scala.util.Left]], and the second one made of those wrapped
* in [[scala.util.Right]].
*
* Example:
* {{{
* val xs = js.Array(1, "one", 2, "two", 3, "three").partitionMap {
* case i: Int => Left(i)
* case s: String => Right(s)
* }
* // xs == (js.Array(1, 2, 3),
* // js.Array("one", "two", "three"))
* }}}
*
* @tparam A1
* the element type of the first resulting collection
* @tparam A2
* the element type of the second resulting collection
* @param f
* the 'split function' mapping the elements of this array to an [[scala.util.Either]]
* @return
* a pair of arrays: the first one made of those values returned by `f`
* that were wrapped in [[scala.util.Left]], and the second one made of
* those wrapped in [[scala.util.Right]].
*/
def partitionMap[A1, A2](f: T => Either[A1, A2])(using ClassTag[A1], ClassTag[A2]): (NArray[A1], NArray[A2]) = {
val b1 = NArrayBuilder[A1]()
val b2 = NArrayBuilder[A2]()

var i = 0; while (i < a.length) {
f(a(i)) match {
case Left(x) => b1.addOne(x)
case Right(x) => b2.addOne(x)
}
i = i + 1
}
(b1.result, b2.result)
}


/** Sorts this array according to a comparison function.
*
* The sort is stable. That is, elements that are equal (as determined by
Expand Down Expand Up @@ -1105,32 +1216,35 @@ object Extensions {
(a1, a2, a3)
}

/** Transposes a two dimensional array.
*
* @tparam B Type of row elements.
* @param asArray A function that converts elements of this array to rows - arrays of type `B`.
* @return An array obtained by replacing elements of this arrays with rows the represent.
*/
def transpose[B](using asArray: T => NArray[B]): NArray[NArray[B]] = {
val aClass = a.getClass.getComponentType
val bb = NArrayBuilder.builderFor[NArray[B]]()
if (a.length == 0) bb.result
else {
def mkRowBuilder() = NArrayBuilder.builderFor[B]()

val bs = asArray(a(0)).map((x: B) => mkRowBuilder())

for (xs <- a) {
var i = 0
for (x <- asArray(xs)) {
bs(i) += x
i += 1
}
}
for (b <- bs) bb += b.result
bb.result
}
}
// /** Transposes a two dimensional array.
// *
// * @tparam B Type of row elements.
// * @param asArray A function that converts elements of this array to rows - arrays of type `B`.
// * @return An array obtained by replacing elements of this arrays with rows the represent.
// */
// def transpose[B](using ctb: ClassTag[B], ctnb: ClassTag[NArray[B]], asArray: T => NArray[B]): NArray[NArray[B]] = {
// val bb = NArrayBuilder[NArray[B]]()
// if (a.length == 0) bb.result
// else {
// val bs = asArray(a(0)).map((x: B) => NArrayBuilder[B]())
//
// var ia = 0; while (ia < a.length) {
// val xs = asArray(a(ia))
// var i = 0
// var ix = 0; while (ix < xs.length) {
// bs(i).addOne(xs(ix))
// ix = ix + 1
// i += 1
// }
// ia = ia + 1
// }
// var ib = 0; while (ib < bs.length) {
// bb.addAll( bs(ib).result )
// ib = ib + 1
// }
// bb.result
// }
// }

/** Apply `f` to each element for side effects.
* Note: [U] parameter needed to help scalac's type inference.
Expand Down Expand Up @@ -1355,7 +1469,7 @@ object Extensions {
}

/** Tests whether this array starts with the given array. */
inline def startsWith[B >: T](that: NArray[B]): Boolean = startsWith(that, 0)
inline def startsWith[B >: T](that: NArray[B]): Boolean = startsWith[B](that, 0)

/** Tests whether this array contains the given array at a given index.
*
Expand All @@ -1365,12 +1479,12 @@ object Extensions {
* index `offset`, otherwise `false`.
*/
def startsWith[B >: T](that: NArray[B], offset: Int): Boolean = {
val safeOffset = offset.max(0)
val thatl = that.length
if (thatl > a.length - safeOffset) thatl == 0
val safeOffset = Math.max(offset, 0)
val thatLength = that.length
if (thatLength > a.length - safeOffset) thatLength == 0
else {
var i = 0
while (i < thatl) {
while (i < thatLength) {
if (a(i + safeOffset) != that(i)) return false
i += 1
}
Expand Down Expand Up @@ -1512,12 +1626,11 @@ object Extensions {
}

/** Iterates over combinations. */
def combinations(n: Int): scala.collection.Iterator[NArray[T]] = ???
//def combinations(n: Int): scala.collection.Iterator[NArray[T]] = ???

/** Iterates over distinct permutations. */
def permutations: scala.collection.Iterator[NArray[T]] = ???
//def permutations: scala.collection.Iterator[NArray[T]] = ???

// we have another overload here, so we need to duplicate this method
/** Tests whether this array contains the given sequence at a given index.
*
* @param that
Expand All @@ -1528,9 +1641,16 @@ object Extensions {
* `true` if the sequence `that` is contained in this array at index
* `offset`, otherwise `false`.
*/
//def startsWith[B >: T](that: IterableOnce[B], offset: Int = 0): Boolean = ???
// def startsWith[B >: T](that: IterableOnce[B], offset: Int = 0): Boolean = {
// val itr = that.iterator
// var out = true
// var i = offset; while (itr.hasNext && i < a.length && out) {
// out = itr.next == a(i)
// i = i + 1
// }
// out
// }

// we have another overload here, so we need to duplicate this method
/** Tests whether this array ends with the given sequence.
*
* @param that
Expand Down
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