strconv: add example for QuotedPrefix

Example can sometimes be more informative than additional prose.

Fixes #46829

Change-Id: Ia5a5b121ad0b891026e77420d5f7f1b2c4a407da
Reviewed-on: https://go-review.googlesource.com/c/go/+/336749
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: qiulaidongfeng <2645477756@qq.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>

diff --git a/src/strconv/example_test.go b/src/strconv/example_test.go
index b02392de6a882030a203b5a87af4275576c44fb8..428fde4e6609c1f831fc9e0cbd382d8746026947 100644 (file)
--- a/src/strconv/example_test.go
+++ b/src/strconv/example_test.go
@@ -369,6 +369,23 @@ func ExampleQuoteToGraphic() {
        // "\" This is a ☺ \\n \""
 }
 
+func ExampleQuotedPrefix() {
+       s, err := strconv.QuotedPrefix("not a quoted string")
+       fmt.Printf("%q, %v\n", s, err)
+       s, err = strconv.QuotedPrefix("\"double-quoted string\" with trailing text")
+       fmt.Printf("%q, %v\n", s, err)
+       s, err = strconv.QuotedPrefix("`or backquoted` with more trailing text")
+       fmt.Printf("%q, %v\n", s, err)
+       s, err = strconv.QuotedPrefix("'\u263a' is also okay")
+       fmt.Printf("%q, %v\n", s, err)
+
+       // Output:
+       // "", invalid syntax
+       // "\"double-quoted string\"", <nil>
+       // "`or backquoted`", <nil>
+       // "'☺'", <nil>
+}
+
 func ExampleUnquote() {
        s, err := strconv.Unquote("You can't unquote a string without quotes")
        fmt.Printf("%q, %v\n", s, err)