builtin: tweak a couple of descriptions.

R=golang-dev, adg, dsymonds
CC=golang-dev
https://golang.org/cl/4875050

diff --git a/src/pkg/builtin/builtin.go b/src/pkg/builtin/builtin.go
index 636aae69349b5e128a5d59de62bd6338b4592ab1..f835580de8576382db7e8477efeba0d9ac5723c7 100644 (file)
--- a/src/pkg/builtin/builtin.go
+++ b/src/pkg/builtin/builtin.go
@@ -45,18 +45,20 @@ func copy(dst, src []Type) int
 
 // The len built-in function returns the length of v, according to its type:
 //     Array: the number of elements in v.
-//     Pointer to array: the number of elements in *v.
-//     Slice, or map: the number of elements in v. If v is nil, len(v) is zero.
+//     Pointer to array: the number of elements in *v (even if v is nil).
+//     Slice, or map: the number of elements in v; if v is nil, len(v) is zero.
 //     String: the number of bytes in v.
-//     Channel: the number of elements queued (unread) in the channel buffer.
-//     If v is nil, len(v) is zero.
+//     Channel: the number of elements queued (unread) in the channel buffer;
+//     if v is nil, len(v) is zero.
 func len(v Type) int
 
 // The cap built-in function returns the capacity of v, according to its type:
 //     Array: the number of elements in v (same as len(v)).
 //     Pointer to array: the number of elements in *v (same as len(v)).
-//     Slice: the maximum length the slice can reach when resliced.
-//     Channel: the maximum channel buffer capacity, in units of elements.
+//     Slice: the maximum length the slice can reach when resliced;
+//     if v is nil, cap(v) is zero.
+//     Channel: the channel buffer capacity, in units of elements;
+//     if v is nil, cap(v) is zero.
 func cap(v Type) int
 
 // The make built-in function allocates and initializes an object of type