sort: document two undocumented functions

They looked out of place in godoc.
Includes documenting sort stability.

Fixes #3356

R=golang-dev, gri, trolleriprofessorn
CC=golang-dev
https://golang.org/cl/5855044

diff --git a/src/pkg/sort/sort.go b/src/pkg/sort/sort.go
index 31da3c83d0d6162e70bfc353dac7dc985f94e93d..60f2d9ab40a1610a10c33671db3c6ce6205881a3 100644 (file)
--- a/src/pkg/sort/sort.go
+++ b/src/pkg/sort/sort.go
@@ -183,6 +183,8 @@ func quickSort(data Interface, a, b, maxDepth int) {
        }
 }
 
+// Sort sorts data.
+// The algorithm used is not guaranteed to be a stable sort.
 func Sort(data Interface) {
        // Switch to heapsort if depth of 2*ceil(lg(n)) is reached.
        n := data.Len()
@@ -194,6 +196,7 @@ func Sort(data Interface) {
        quickSort(data, 0, n, maxDepth)
 }
 
+// IsSorted reports whether data is sorted.
 func IsSorted(data Interface) bool {
        n := data.Len()
        for i := n - 1; i > 0; i-- {