Support url.URL.

mapper.go

@@ -3,6 +3,7 @@ package kong
 import (
 	"fmt"
 	"math/bits"
+	"net/url"
 	"os"
 	"reflect"
 	"strconv"
@@ -162,10 +163,11 @@ func (r *Registry) RegisterDefaults() *Registry {
 			return nil
 		})).
 		RegisterKind(reflect.Bool, boolMapper{}).
-		RegisterType(reflect.TypeOf(time.Time{}), timeDecoder()).
-		RegisterType(reflect.TypeOf(time.Duration(0)), durationDecoder()).
 		RegisterKind(reflect.Slice, sliceDecoder(r)).
 		RegisterKind(reflect.Map, mapDecoder(r)).
+		RegisterType(reflect.TypeOf(time.Time{}), timeDecoder()).
+		RegisterType(reflect.TypeOf(time.Duration(0)), durationDecoder()).
+		RegisterType(reflect.TypeOf(&url.URL{}), urlMapper()).
 		RegisterName("path", pathMapper(r)).
 		RegisterName("existingfile", existingFileMapper(r)).
 		RegisterName("existingdir", existingDirMapper(r))
@@ -360,6 +362,17 @@ func existingDirMapper(r *Registry) MapperFunc {
 	}
 }
 
+func urlMapper() MapperFunc {
+	return func(ctx *DecodeContext, target reflect.Value) error {
+		url, err := url.Parse(ctx.Scan.PopValue("url"))
+		if err != nil {
+			return err
+		}
+		target.Set(reflect.ValueOf(url))
+		return nil
+	}
+}
+
 // SplitEscaped splits a string on a separator.
 //
 // It differs from strings.Split() in that the separator can exist in a field by escaping it with a \. eg.

mapper_test.go

@@ -1,6 +1,7 @@
 package kong
 
 import (
+	"net/url"
 	"reflect"
 	"testing"
 	"time"
@@ -95,3 +96,15 @@ func TestMapWithNamedTypes(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, map[string]string{"FIRST": "5s", "SECOND": "10s"}, cli.TypedKey)
 }
+
+func TestURLMapper(t *testing.T) {
+	var cli struct {
+		URL *url.URL `arg:""`
+	}
+	p := mustNew(t, &cli)
+	_, err := p.Parse([]string{"http://w3.org"})
+	require.NoError(t, err)
+	require.Equal(t, "http://w3.org", cli.URL.String())
+	_, err = p.Parse([]string{":foo"})
+	require.Error(t, err)
+}