Complete #14 and #15 url{en,de}code filters

README.md

@@ -32,7 +32,7 @@ In brief, these aren't implemented:
 
 - The `cycle` and `tablerow` tags
 - `{% when a or b %}`
-- The `sort_natural`, `url_decode`, and `url_encode` filters
+- The `sort_natural` filter
 - Loop ranges `{% for a in 1...10 %}`
 - Error modes
 - Whitespace control

filters/standard_filters.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"html"
 	"math"
+	"net/url"
 	"reflect"
 	"regexp"
 	"strings"
@@ -190,6 +191,8 @@ func AddStandardFilters(fd FilterDictionary) { // nolint: gocyclo
 	fd.AddFilter("upcase", func(s, suffix string) string {
 		return strings.ToUpper(s)
 	})
+	fd.AddFilter("url_encode", url.QueryEscape)
+	fd.AddFilter("url_decode", url.QueryUnescape)
 
 	// debugging extensions
 	// inspect is from Jekyll

filters/standard_filters_test.go

@@ -96,6 +96,10 @@ var filterTests = []struct {
 	{`"          So much room for activities!          " | lstrip`, "So much room for activities!          "},
 	{`"          So much room for activities!          " | rstrip`, "          So much room for activities!"},
 
+	{`"%27Stop%21%27+said+Fred" | url_decode`, "'Stop!' said Fred"},
+	{`"john@liquid.com" | url_encode`, "john%40liquid.com"},
+	{`"Tetsuro Takara" | url_encode`, "Tetsuro+Takara"},
+
 	// number filters
 	{`-17 | abs`, 17},
 	{`4 | abs`, 4},