squash merge from dev branch

vendor/gopkg.in/alecthomas/kingpin.v2/examples_test.go

@@ -0,0 +1,46 @@
+package kingpin
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+)
+
+type HTTPHeaderValue http.Header
+
+func (h *HTTPHeaderValue) Set(value string) error {
+	parts := strings.SplitN(value, ":", 2)
+	if len(parts) != 2 {
+		return fmt.Errorf("expected HEADER:VALUE got '%s'", value)
+	}
+	(*http.Header)(h).Add(parts[0], parts[1])
+	return nil
+}
+
+func (h *HTTPHeaderValue) Get() interface{} {
+	return (http.Header)(*h)
+}
+
+func (h *HTTPHeaderValue) String() string {
+	return ""
+}
+
+func HTTPHeader(s Settings) (target *http.Header) {
+	target = new(http.Header)
+	s.SetValue((*HTTPHeaderValue)(target))
+	return
+}
+
+// This example ilustrates how to define custom parsers. HTTPHeader
+// cumulatively parses each encountered --header flag into a http.Header struct.
+func ExampleValue() {
+	var (
+		curl    = New("curl", "transfer a URL")
+		headers = HTTPHeader(curl.Flag("headers", "Add HTTP headers to the request.").Short('H').PlaceHolder("HEADER:VALUE"))
+	)
+
+	curl.Parse([]string{"-H Content-Type:application/octet-stream"})
+	for key, value := range *headers {
+		fmt.Printf("%s = %s\n", key, value)
+	}
+}