Add dateFormat template function

This is the implementation of the proposal at #235 and
http://discuss.gohugo.io/t/parsing-dates-in-templates/603/3

diff --git a/docs/content/templates/functions.md b/docs/content/templates/functions.md
index 89c866951ab92dc5137037855069747e06d3cf46..d84d8ad393422b3e997a1628b12429466da39982 100644 (file)
--- a/docs/content/templates/functions.md
+++ b/docs/content/templates/functions.md
@@ -391,6 +391,11 @@ Replace all occurences of the search string with the replacement string.
 
 e.g. `{{ replace "Batman and Robin" "Robin" "Catwoman" }}` → "Batman and Catwoman"
 
+### dateFormat
+Converts the textual representation of the datetime into the other form or returns it of Go `time.Time` type value. These are formatted with the layout string.
+
+e.g. `{{ dateFormat "Monday, Jan 2, 2006" "2015-01-21" }}` →"Wednesday, Jan 21, 2015"
+
 ### highlight
 Take a string of code and a language, uses Pygments to return the syntax highlighted code in HTML. Used in the [highlight shortcode](/extras/highlighting).
 

diff --git a/tpl/template.go b/tpl/template.go
index 97b2e5bbb3633b398ae6fda668e2c868f3cf1af8..98380bbcbee29a4c2266b79de070bbc8788324f4 100644 (file)
--- a/tpl/template.go
+++ b/tpl/template.go
@@ -905,6 +905,17 @@ func Replace(a, b, c interface{}) (string, error) {
        return strings.Replace(aStr, bStr, cStr, -1), nil
 }
 
+// DateFormat converts the textual representation of the datetime string into
+// the other form or returns it of the time.Time value. These are formatted
+// with the layout string
+func DateFormat(layout string, v interface{}) (string, error) {
+       t, err := cast.ToTimeE(v)
+       if err != nil {
+               return "", err
+       }
+       return t.Format(layout), nil
+}
+
 func SafeHtml(text string) template.HTML {
        return template.HTML(text)
 }
@@ -1281,6 +1292,7 @@ func init() {
                "chomp":       Chomp,
                "replace":     Replace,
                "trim":        Trim,
+               "dateFormat":  DateFormat,
        }
 
 }

diff --git a/tpl/template_test.go b/tpl/template_test.go
index 96bca3c02307b8c3fc9f434cb059f579ee72a6c1..4477d0d26a29507c0a8536eb7eb3c2939bf29035 100644 (file)
--- a/tpl/template_test.go
+++ b/tpl/template_test.go
@@ -10,6 +10,7 @@ import (
        "reflect"
        "runtime"
        "testing"
+       "time"
 )
 
 type tstNoStringer struct {
@@ -988,6 +989,35 @@ func TestTrim(t *testing.T) {
        assert.NotNil(t, e, "tstNoStringer isn't trimmable")
 }
 
+func TestDateFormat(t *testing.T) {
+       for i, this := range []struct {
+               layout string
+               value interface{}
+               expect interface{}
+       }{
+               {"Monday, Jan 2, 2006", "2015-01-21", "Wednesday, Jan 21, 2015"},
+               {"Monday, Jan 2, 2006", time.Date(2015, time.January, 21, 0, 0, 0, 0, time.UTC), "Wednesday, Jan 21, 2015"},
+               {"This isn't a date layout string", "2015-01-21", "This isn't a date layout string"},
+               {"Monday, Jan 2, 2006", 1421733600, false},
+               {"Monday, Jan 2, 2006", 1421733600.123, false},
+       } {
+               result, err := DateFormat(this.layout, this.value)
+               if b, ok := this.expect.(bool); ok && !b {
+                       if err == nil {
+                               t.Errorf("[%d] DateFormat didn't return an expected error", i)
+                       }
+               } else {
+                       if err != nil {
+                               t.Errorf("[%d] DateFormat failed: %s", i, err)
+                               continue
+                       }
+                       if result != this.expect {
+                               t.Errorf("[%d] DateFormat got %v but expected %v", i, result, this.expect)
+                       }
+               }
+       }
+}
+
 func TestSafeHtml(t *testing.T) {
        for i, this := range []struct {
                str                 string