aboutsummaryrefslogtreecommitdiff
path: root/tests/pending/pos/tcpoly_seq.scala
diff options
context:
space:
mode:
Diffstat (limited to 'tests/pending/pos/tcpoly_seq.scala')
-rw-r--r--tests/pending/pos/tcpoly_seq.scala175
1 files changed, 0 insertions, 175 deletions
diff --git a/tests/pending/pos/tcpoly_seq.scala b/tests/pending/pos/tcpoly_seq.scala
deleted file mode 100644
index e8711d1c4..000000000
--- a/tests/pending/pos/tcpoly_seq.scala
+++ /dev/null
@@ -1,175 +0,0 @@
-package examples.tcpoly.collection;
-
-trait HOSeq {
- // an internal interface that encapsulates the accumulation of elements (of type elT) to produce
- // a structure of type coll[elT] -- different kinds of collections should provide different implicit
- // values implementing this interface, in order to provide more performant ways of building that structure
- trait Accumulator[+coll[x], elT] {
- def += (el: elT): Unit
- def result: coll[elT]
- }
-
-
- // Iterable abstracts over the type of its structure as well as its elements (see PolyP's Bifunctor)
- // m[x] is intentionally unbounded: fold can then be defined nicely
- // variance: if we write m[+x] instead of +m[+x], x is an invariant position because its enclosing type
- // is an invariant position -- should probably rule that out?
- trait Iterable[+m[+x], +t] {
- //def unit[a](orig: a): m[a]
- def iterator: Iterator[t]
-
- // construct an empty accumulator that will produce the same structure as this iterable, with elements of type t
- def accumulator[t]: Accumulator[m, t]
-
- def filter(p: t => Boolean): m[t] = {
- val buf = accumulator[t]
- val elems = iterator
- while (elems.hasNext) { val x = elems.next; if (p(x)) buf += x }
- buf.result
- }
-
- def map[s](f: t => s): m[s] = {
- val buf = accumulator[s]
- val elems = iterator
- while (elems.hasNext) buf += f(elems.next)
- buf.result
- }
-
- // flatMap is a more specialized map, it only works if the mapped function produces Iterable values,
- // which are then added to the result one by one
- // the compiler should be able to find the right accumulator (implicit buf) to build the result
- // to get concat, resColl = SingletonIterable, f = unit for SingletonIterable
- def flatMap[resColl[+x] <: Iterable[resColl, x], s](f: t => resColl[s])(implicit buf: Accumulator[resColl, s]): resColl[s] = {
- // TODO: would a viewbound for resColl[x] be better?
- // -- 2nd-order type params are not yet in scope in view bound
- val elems = iterator
- while (elems.hasNext) {
- val elemss: Iterator[s] = f(elems.next).iterator
- while (elemss.hasNext) buf += elemss.next
- }
- buf.result
- }
- }
-
- final class ListBuffer[A] {
- private var start: List[A] = Nil
- private var last: ::[A] = _
- private var exported: Boolean = false
-
- /** Appends a single element to this buffer.
- *
- * @param x the element to append.
- */
- def += (x: A): Unit = {
- if (exported) copy
- if (start.isEmpty) {
- last = new HOSeq.this.:: (x, Nil)
- start = last
- } else {
- val last1 = last
- last = new HOSeq.this.:: (x, null) // hack: ::'s tail will actually be last
- //last1.tl = last
- }
- }
-
- /** Converts this buffer to a list
- */
- def toList: List[A] = {
- exported = !start.isEmpty
- start
- }
-
- /** Clears the buffer contents.
- */
- def clear: Unit = {
- start = Nil
- exported = false
- }
-
- /** Copy contents of this buffer */
- private def copy: Unit = {
- var cursor = start
- val limit = last.tail
- clear
- while (cursor ne limit) {
- this += cursor.head
- cursor = cursor.tail
- }
- }
- }
-
- implicit def listAccumulator[elT]: Accumulator[List, elT] = new Accumulator[List, elT] {
- private[this] val buff = new ListBuffer[elT]
- def += (el: elT): Unit = buff += el
- def result: List[elT] = buff.toList
- }
-
- trait List[+t] extends Iterable[List, t] {
- def head: t
- def tail: List[t]
- def isEmpty: Boolean
- def iterator: Iterator[t] = new Iterator[t] {
- var these = List.this
- def hasNext: Boolean = !these.isEmpty
- def next: t =
- if (!hasNext)
- throw new NoSuchElementException("next on empty Iterator")
- else {
- val result = these.head; these = these.tail; result
- }
- }
- // construct an empty accumulator that will produce the same structure as this iterable, with elements of type t
- def accumulator[t]: Accumulator[List, t] = listAccumulator[t]
- }
-
- // TODO: the var tl approach does not seem to work because subtyping isn't fully working yet
- final case class ::[+b](hd: b, private val tl: List[b]) extends List[b] {
- def head = hd
- def tail = if (tl==null) this else tl // hack
- override def isEmpty: Boolean = false
- }
-
- case object Nil extends List[Nothing] {
- def isEmpty = true
- def head: Nothing =
- throw new NoSuchElementException("head of empty list")
- def tail: List[Nothing] =
- throw new NoSuchElementException("tail of empty list")
- }
-}
-
-
-
-// misc signatures collected from mailing list / library code:
- /*override def flatMap[B](f: A => Iterable[B]): Set[B]
- final override def flatMap[b](f: Any => Iterable[b]): Array[b]
- def flatMap[b](f: a => Parser[b]) = new Parser[b]
- override def flatMap[b](f: a => Iterable[b]): List[b]
-
-
- MapResult[K] <: Seq[K]
- FilterResult <: Seq[T]
- Concat <: Seq[T]
- Subseq <: Seq[T]
-
-
- def map[K](f: T=>K): MapResult[K]
- def filter(f: T=>Boolean): FilterResult
- def subseq(from: Int, to: Int): Subseq
- def flatMap[S <: Seq[K], K](f: T => S): S#Concat // legal?
- def concat(others: Seq[T]): Concat
- */
-
-/*trait Iterator[t] {
- // @post hasAdvanced implies hasNext
- // model def hasAdvanced: Boolean
-
- def hasNext: Boolean // pure
-
- // @pre hasAdvanced
- def current: t // pure
-
- // @pre hasNext
- // @post hasAdvanced
- def advance: Unit
-}*/