2 files changed, 30 insertions, 1 deletions
diff --git a/src/lib/container/array/array.go b/src/lib/container/array/array.go
index 768e46d3a..e29736fb6 100644
--- a/src/lib/container/array/array.go
+++ b/src/lib/container/array/array.go
@@ -140,6 +140,13 @@ func (p *Array) Slice(i, j int) *Array {
 }
 
 
+func (p *Array) Do(f func(elem Element)) {
+	for i := 0; i < len(p.a); i++ {
+		f(p.a[i])	// not too safe if f changes the Array
+	}
+}
+
+
 // Convenience wrappers
 
 func (p *Array) Push(x Element) {
diff --git a/src/lib/container/array/array_test.go b/src/lib/container/array/array_test.go
index df9fee673..43ac702ab 100644
--- a/src/lib/container/array/array_test.go
+++ b/src/lib/container/array/array_test.go
@@ -139,7 +139,6 @@ func TestInsertArray(t *testing.T) {
 	verify_pattern(t, a, 8, 1000, 2);
 }
 
-
 func TestSorting(t *testing.T) {
 	const n = 100;
 	a := array.NewIntArray(n);
@@ -148,3 +147,26 @@ func TestSorting(t *testing.T) {
 	}
 	if sort.IsSorted(a) { t.Error("not sorted") }
 }
+
+
+func TestDo(t *testing.T) {
+	const n = 25;
+	const salt = 17;
+	a := array.NewIntArray(n);
+	for i := 0; i < n; i++ {
+		a.Set(i, salt * i);
+	}
+	count := 0;
+	a.Do(
+		func(e array.Element) {
+			i := e.(int);
+			if i != count*salt {
+				t.Error("value at", count, "should be", count*salt, "not", i)
+			}
+			count++;
+		}
+	);
+	if count != n {
+		t.Error("should visit", n, "values; did visit", count)
+	}
+}