Added strings.FieldsFunc, a generalization of strings.Fields in style of the strings...

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/824051

diff --git a/src/pkg/strings/strings.go b/src/pkg/strings/strings.go
index 0a9f64ca0ca7198284fe2096577a36fbaa496179..90417f811d060c25163ef1a93377c8a9afafd2ba 100644 (file)
--- a/src/pkg/strings/strings.go
+++ b/src/pkg/strings/strings.go
@@ -172,12 +172,19 @@ func SplitAfter(s, sep string, n int) []string {
 // Fields splits the string s around each instance of one or more consecutive white space
 // characters, returning an array of substrings of s or an empty list if s contains only white space.
 func Fields(s string) []string {
+       return FieldsFunc(s, unicode.IsSpace)
+}
+
+// FieldsFunc splits the string s at each run of Unicode code points c satifying f(c)
+// and returns an array of slices of s. If no code points in s satisfy f(c), an empty slice
+// is returned.
+func FieldsFunc(s string, f func(int) bool) []string {
        // First count the fields.
        n := 0
        inField := false
        for _, rune := range s {
                wasInField := inField
-               inField = !unicode.IsSpace(rune)
+               inField = !f(rune)
                if inField && !wasInField {
                        n++
                }
@@ -188,7 +195,7 @@ func Fields(s string) []string {
        na := 0
        fieldStart := -1 // Set to -1 when looking for start of field.
        for i, rune := range s {
-               if unicode.IsSpace(rune) {
+               if f(rune) {
                        if fieldStart >= 0 {
                                a[na] = s[fieldStart:i]
                                na++

diff --git a/src/pkg/strings/strings_test.go b/src/pkg/strings/strings_test.go
index 6c2bd727d765fb3f1b9800e1347baaeab65915cc..3c9dc5847a70ac4b8c78fbadd8a8a22227fbde6b 100644 (file)
--- a/src/pkg/strings/strings_test.go
+++ b/src/pkg/strings/strings_test.go
@@ -222,6 +222,22 @@ func TestFields(t *testing.T) {
        }
 }
 
+func TestFieldsFunc(t *testing.T) {
+       pred := func(c int) bool { return c == 'X' }
+       var fieldsFuncTests = []FieldsTest{
+               FieldsTest{"", []string{}},
+               FieldsTest{"XX", []string{}},
+               FieldsTest{"XXhiXXX", []string{"hi"}},
+               FieldsTest{"aXXbXXXcX", []string{"a", "b", "c"}},
+       }
+       for _, tt := range fieldsFuncTests {
+               a := FieldsFunc(tt.s, pred)
+               if !eq(a, tt.a) {
+                       t.Errorf("FieldsFunc(%q) = %v, want %v", tt.s, a, tt.a)
+               }
+       }
+}
+
 
 // Test case for any function which accepts and returns a single string.
 type StringTest struct {