Add support for TextMarshalers

pretty/public.go

@@ -35,6 +35,7 @@ type Config struct {
 	// Field and value options
 	IncludeUnexported bool // Include unexported fields in output
 	PrintStringers    bool // Call String on a fmt.Stringer
+	NoTextMarshalers  bool // Don't automatically call MarshalText
 	SkipZeroFields    bool // Skip struct fields that have a zero value.
 
 	// Output transforms

pretty/reflect.go

@@ -15,6 +15,7 @@
 package pretty
 
 import (
+	"encoding"
 	"fmt"
 	"reflect"
 	"sort"
@@ -31,10 +32,15 @@ func isZeroVal(val reflect.Value) bool {
 func (c *Config) val2node(val reflect.Value) node {
 	// TODO(kevlar): pointer tracking?
 
-	if c.PrintStringers && val.CanInterface() {
-		stringer, ok := val.Interface().(fmt.Stringer)
-		if ok {
-			return stringVal(stringer.String())
+	if val.CanInterface() {
+		v := val.Interface()
+		if s, ok := v.(fmt.Stringer); ok && c.PrintStringers {
+			return stringVal(s.String())
+		}
+		if t, ok := v.(encoding.TextMarshaler); ok && !c.NoTextMarshalers {
+			if raw, err := t.MarshalText(); err == nil { // if NOT an error
+				return stringVal(string(raw))
+			}
 		}
 	}
 

pretty/reflect_test.go

@@ -15,6 +15,7 @@
 package pretty
 
 import (
+	"net"
 	"reflect"
 	"testing"
 	"time"
@@ -78,6 +79,11 @@ func TestVal2nodeDefault(t *testing.T) {
 			3,
 			rawVal("3"),
 		},
+		{
+			"TextMarshaler",
+			net.ParseIP("dead:beef::1"),
+			stringVal("dead:beef::1"),
+		},
 	}
 
 	for _, test := range tests {
@@ -120,7 +126,17 @@ func TestVal2node(t *testing.T) {
 			struct{ Date time.Time }{time.Unix(1234567890, 0).UTC()},
 			DefaultConfig,
 			keyvals{
-				{"Date", keyvals{}}, // empty struct, it has unexported fields
+				{"Date", stringVal("2009-02-13T23:31:30Z")},
+			},
+		},
+		{
+			"time w/o TextMarshalers",
+			struct{ Date time.Time }{time.Unix(1234567890, 0).UTC()},
+			&Config{
+				NoTextMarshalers: true,
+			},
+			keyvals{
+				{"Date", keyvals{}},
 			},
 		},
 		{