Add support for marshaling durations.

decode.go

diff --git a/decode.go b/decode.go
index ab2b8f7..9480191 100644
--- a/decode.go
+++ b/decode.go
@@ -3,6 +3,7 @@
 import (
 	"reflect"
 	"strconv"
+	"time"
 )
 
 const (
@@ -279,6 +280,8 @@
 	return good
 }
 
+var durationType = reflect.TypeOf(time.Duration(0))
+
 func (d *decoder) scalar(n *node, out reflect.Value) (good bool) {
 	var tag string
 	var resolved interface{}
@@ -321,6 +324,14 @@
 				out.SetInt(int64(resolved))
 				good = true
 			}
+		case string:
+			if out.Type() == durationType {
+				d, err := time.ParseDuration(resolved)
+				if err == nil {
+					out.SetInt(int64(d))
+					good = true
+				}
+			}
 		}
 	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
 		switch resolved := resolved.(type) {

decode_test.go

diff --git a/decode_test.go b/decode_test.go
index 5702909..ab3a7fb 100644
--- a/decode_test.go
+++ b/decode_test.go
@@ -1,10 +1,11 @@
 package yaml_test
 
 import (
-	. "launchpad.net/gocheck"
+	. "gopkg.in/check.v1"
 	"gopkg.in/yaml.v1"
 	"math"
 	"reflect"
+	"time"
 )
 
 var unmarshalIntTest = 123
@@ -364,6 +365,12 @@
 		"a: 50cent_of_dollar",
 		map[string]interface{}{"a": "50cent_of_dollar"},
 	},
+
+	// Duration
+	{
+		"a: 3s",
+		map[string]time.Duration{"a": 3 * time.Second},
+	},
 }
 
 type inlineB struct {

encode.go

diff --git a/encode.go b/encode.go
index c700443..1d928b0 100644
--- a/encode.go
+++ b/encode.go
@@ -4,6 +4,7 @@
 	"reflect"
 	"sort"
 	"strconv"
+	"time"
 )
 
 type encoder struct {
@@ -85,7 +86,11 @@
 	case reflect.String:
 		e.stringv(tag, in)
 	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-		e.intv(tag, in)
+		if in.Type() == durationType {
+			e.stringv(tag, reflect.ValueOf(in.Interface().(time.Duration).String()))
+		} else {
+			e.intv(tag, in)
+		}
 	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
 		e.uintv(tag, in)
 	case reflect.Float32, reflect.Float64:

encode_test.go

diff --git a/encode_test.go b/encode_test.go
index 0ab65b9..c7461d5 100644
--- a/encode_test.go
+++ b/encode_test.go
@@ -2,11 +2,12 @@
 
 import (
 	"fmt"
-	. "launchpad.net/gocheck"
 	"gopkg.in/yaml.v1"
+	. "gopkg.in/check.v1"
 	"math"
 	"strconv"
 	"strings"
+	"time"
 )
 
 var marshalIntTest = 123
@@ -212,6 +213,12 @@
 		}{1, inlineB{2, inlineC{3}}},
 		"a: 1\nb: 2\nc: 3\n",
 	},
+
+	// Duration
+	{
+		map[string]time.Duration{"a": 3 * time.Second},
+		"a: 3s\n",
+	},
 }
 
 func (s *S) TestMarshal(c *C) {

suite_test.go

diff --git a/suite_test.go b/suite_test.go
index 111d756..c5cf1ed 100644
--- a/suite_test.go
+++ b/suite_test.go
@@ -1,7 +1,7 @@
 package yaml_test
 
 import (
-	. "launchpad.net/gocheck"
+	. "gopkg.in/check.v1"
 	"testing"
 )