Add new functions to the iterable package:

- Filter
- Find
- Partition

R=rsc
APPROVED=rsc
DELTA=117  (92 added, 17 deleted, 8 changed)
OCL=27135
CL=27240

1 files changed, 50 insertions, 9 deletions

diff --git a/src/lib/container/iterable_test.go b/src/lib/container/iterable_test.go
index 9c7d29110..702ebe861 100644
--- a/src/lib/container/iterable_test.go
+++ b/src/lib/container/iterable_test.go
@@ -43,6 +43,17 @@ func addOne(n interface {}) interface {} {
 	return n.(int) + 1
 }
 
+// A stream of the natural numbers: 0, 1, 2, 3, ...
+type integerStream struct {}
+func (i integerStream) Iter() <-chan interface {} {
+  ch := make(chan interface {});
+  go func() {
+    for i := 0; ; i++ {
+      ch <- i
+    }
+  }();
+  return ch
+}
 
 func TestAll(t *testing.T) {
 	if !All(oneToFive, isPositive) {
@@ -53,7 +64,6 @@ func TestAll(t *testing.T) {
 	}
 }
 
-
 func TestAny(t *testing.T) {
 	if Any(oneToFive, isNegative) {
 		t.Error("Any(oneToFive, isNegative) == true")
@@ -63,16 +73,47 @@ func TestAny(t *testing.T) {
 	}
 }
 
-
-func TestMap(t *testing.T) {
-	res := Data(Map(Map(oneToFive, doubler), addOne));
-	if len(res) != len(oneToFive) {
-		t.Fatal("len(res) = %v, want %v", len(res), len(oneToFive))
+func assertArraysAreEqual(t *testing.T, res []interface {}, expected []int) {
+	if len(res) != len(expected) {
+		t.Errorf("len(res) = %v, want %v", len(res), len(expected));
+		goto missing
 	}
-	expected := []int{ 3, 5, 7, 9, 11 };
 	for i := range res {
-		if res[i].(int) != expected[i] {
-			t.Errorf("res[%v] = %v, want %v", i, res[i], expected[i])
+		if v := res[i].(int); v != expected[i] {
+			t.Errorf("res[%v] = %v, want %v", i, v, expected[i]);
+			goto missing
 		}
 	}
+	return;
+missing:
+	t.Errorf("res = %v\nwant  %v", res, expected);
+}
+
+func TestFilter(t *testing.T) {
+	ints := integerStream{};
+	moreInts := Filter(ints, isAbove3).Iter();
+	res := make([]interface {}, 3);
+	for i := 0; i < 3; i++ {
+		res[i] = <-moreInts;
+	}
+	assertArraysAreEqual(t, res, []int{ 4, 5, 6 })
+}
+
+func TestFind(t *testing.T) {
+	ints := integerStream{};
+	first := Find(ints, isAbove3);
+	if first.(int) != 4 {
+		t.Errorf("Find(ints, isAbove3) = %v, want 4", first)
+	}
+}
+
+func TestMap(t *testing.T) {
+	res := Data(Map(Map(oneToFive, doubler), addOne));
+	assertArraysAreEqual(t, res, []int{ 3, 5, 7, 9, 11 })
+}
+
+func TestPartition(t *testing.T) {
+	ti, fi := Partition(oneToFive, isEven);
+	assertArraysAreEqual(t, Data(ti), []int{ 2, 4 });
+	assertArraysAreEqual(t, Data(fi), []int{ 1, 3, 5 })
 }