strings: Add ContainsAny and ContainsRune to correspond to IndexAny etc.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5430046

1 files changed, 13 insertions, 3 deletions

diff --git a/src/pkg/strings/strings.go b/src/pkg/strings/strings.go
index b4d920714a..53fdeadf97 100644
--- a/src/pkg/strings/strings.go
+++ b/src/pkg/strings/strings.go
@@ -64,7 +64,17 @@ func Count(s, sep string) int {
 
 // Contains returns true if substr is within s.
 func Contains(s, substr string) bool {
-	return Index(s, substr) != -1
+	return Index(s, substr) >= 0
+}
+
+// ContainsAny returns true if any Unicode code points in chars are within s.
+func ContainsAny(s, chars string) bool {
+	return IndexAny(s, chars) >= 0
+}
+
+// ContainsRune returns true if the Unicode code point r is within s.
+func ContainsRune(s string, r rune) bool {
+	return IndexRune(s, r) >= 0
 }
 
 // Index returns the index of the first instance of sep in s, or -1 if sep is not present in s.
@@ -269,7 +279,7 @@ func FieldsFunc(s string, f func(rune) bool) []string {
 			fieldStart = i
 		}
 	}
-	if fieldStart != -1 { // Last field might end at EOF.
+	if fieldStart >= 0 { // Last field might end at EOF.
 		a[na] = s[fieldStart:]
 	}
 	return a
@@ -512,7 +522,7 @@ func lastIndexFunc(s string, f func(rune) bool, truth bool) int {
 }
 
 func makeCutsetFunc(cutset string) func(rune) bool {
-	return func(r rune) bool { return IndexRune(cutset, r) != -1 }
+	return func(r rune) bool { return IndexRune(cutset, r) >= 0 }
 }
 
 // Trim returns a slice of the string s with all leading and