More filters

README.md

@@ -32,8 +32,7 @@ This is currently 5-30x faster than Jekyll, depending on the use of `{% highligh
 - [ ] Customization
   - [x] Templates
     - [ ] Jekyll filters
-      - [ ] array filters: `group_by_exp` `sample` `pop` `shift`
-      - [ ] string filters: `cgi_escape` `uri_escape` `scssify` `smartify` `slugify` `normalize_whitespace`
+      - [ ] `group_by_exp` `pop` `shift` `cgi_escape` `uri_escape` `scssify` `smartify`
       - [x] everything else
     - [ ] Jekyll tags
       - [x] `include`

filters/filters.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"encoding/xml"
 	"fmt"
+	"math/rand"
 	"reflect"
 	"regexp"
 	"strings"
@@ -31,6 +32,13 @@ func AddJekyllFilters(engine liquid.Engine, config config.Config) {
 		return out
 	})
 	engine.DefineFilter("group_by", groupByFilter)
+	engine.DefineFilter("group_by_exp", unimplementedFilter("group_by_exp"))
+	engine.DefineFilter("sample", func(array []interface{}) interface{} {
+		if len(array) == 0 {
+			return nil
+		}
+		return array[rand.Intn(len(array))]
+	})
 	// sort overrides the Liquid filter with one that takes parameters
 	engine.DefineFilter("sort", sortFilter)
 	engine.DefineFilter("where", whereFilter) // TODO test case
@@ -40,6 +48,8 @@ func AddJekyllFilters(engine liquid.Engine, config config.Config) {
 	engine.DefineFilter("push", func(array []interface{}, item interface{}) interface{} {
 		return append(array, generics.MustConvertItem(item, array))
 	})
+	engine.DefineFilter("pop", unimplementedFilter("pop"))
+	engine.DefineFilter("shift", unimplementedFilter("shift"))
 	engine.DefineFilter("unshift", func(array []interface{}, item interface{}) interface{} {
 		return append([]interface{}{generics.MustConvertItem(item, array)}, array...)
 	})
@@ -71,10 +81,25 @@ func AddJekyllFilters(engine liquid.Engine, config config.Config) {
 	})
 	engine.DefineFilter("jsonify", json.Marshal)
 	engine.DefineFilter("markdownify", blackfriday.MarkdownCommon)
-	// engine.DefineFilter("normalize_whitespace", func(s string) string {
-	// 	wsPattern := regexp.MustCompile(`(?s:[\s\n]+)`)
-	// 	return wsPattern.ReplaceAllString(s, " ")
-	// })
+	engine.DefineFilter("normalize_whitespace", func(s string) string {
+		// s = strings.Replace(s, "n", "N", -1)
+		wsPattern := regexp.MustCompile(`(?s:[\s\n]+)`)
+		return wsPattern.ReplaceAllString(s, " ")
+	})
+	engine.DefineFilter("slugify", func(s, mode string) string {
+		if mode == "" {
+			mode = "default"
+		}
+		p := map[string]string{
+			"raw":     `\s+`,
+			"default": `[^[:alnum:]]+`,
+			"pretty":  `[^[:alnum:]\._~!$&'()+,;=@]+`,
+		}[mode]
+		if p != "" {
+			s = regexp.MustCompile(p).ReplaceAllString(s, "-")
+		}
+		return strings.ToLower(s)
+	})
 	engine.DefineFilter("to_integer", func(n int) int { return n })
 	engine.DefineFilter("number_of_words", func(s string) int {
 		wordPattern := regexp.MustCompile(`\w+`) // TODO what's the Jekyll spec for a word?
@@ -94,6 +119,10 @@ func AddJekyllFilters(engine liquid.Engine, config config.Config) {
 	// 	}
 	// 	return strings.Join(parts, "?")
 	// })
+	engine.DefineFilter("cgi_escape", unimplementedFilter("cgi_escape"))
+	engine.DefineFilter("uri_escape", unimplementedFilter("uri_escape"))
+	engine.DefineFilter("scssify", unimplementedFilter("scssify"))
+	engine.DefineFilter("smartify", unimplementedFilter("smartify"))
 	engine.DefineFilter("xml_escape", func(s string) string {
 		// TODO can't handle maps
 		// eval https://github.com/clbanning/mxj
@@ -106,6 +135,17 @@ func AddJekyllFilters(engine liquid.Engine, config config.Config) {
 	})
 }
 
+func unimplementedFilter(name string) func(value interface{}) interface{} {
+	warned := false
+	return func(value interface{}) interface{} {
+		if !warned {
+			fmt.Println("warning: unimplemented filter:", name)
+			warned = true
+		}
+		return value
+	}
+}
+
 func arrayToSentenceStringFilter(array []string, conjunction interface{}) string {
 	conj, ok := conjunction.(string)
 	if !ok {

filters/filters_test.go

@@ -2,6 +2,7 @@ package filters
 
 import (
 	"fmt"
+	"math/rand"
 	"strings"
 	"testing"
 	"time"
@@ -22,7 +23,10 @@ var filterTests = []struct{ in, expected string }{
 	// arrays
 	// TODO group_by group_by_exp sample pop shift
 	// pop and shift are challenging because they require lvalues
-	{`{{ ar | array_to_sentence_string }}`, "first, second, and third"},
+	{`{{ array | array_to_sentence_string }}`, "first, second, and third"},
+	{`{{ array | sample }}`, "third"},
+
+	{`{{ site.members | group_by: "graduation_year" | map: "name" | sort | join }}`, "2013, 2014, 2015"},
 
 	// TODO what is the default for nil first?
 	{`{{ animals | sort | join: ", " }}`, "Sally Snake, giraffe, octopus, zebra"},
@@ -34,7 +38,6 @@ var filterTests = []struct{ in, expected string }{
 	{`{{ site.members | where_exp: "item", "item.graduation_year == 2014" | map: "name" }}`, "Alan"},
 	{`{{ site.members | where_exp: "item", "item.graduation_year < 2014" | map: "name" }}`, "Alonzo"},
 	{`{{ site.members | where_exp: "item", "item.name contains 'Al'" | map: "name" | join }}`, "Alonzo, Alan"},
-	{`{{ site.members | group_by: "graduation_year" | map: "name" | sort | join }}`, "2013, 2014, 2015"},
 
 	{`{{ page.tags | push: 'Spokane' | join }}`, "Seattle, Tacoma, Spokane"},
 	// {`{{ page.tags | pop }}`, "Seattle"},
@@ -49,18 +52,25 @@ var filterTests = []struct{ in, expected string }{
 	{`{{ obj | jsonify }}`, `{"a":[1,2,3,4]}`},
 	{`{{ site.pages | map: "name" | join }}`, "a, b, c, d"},
 	{`{{ site.pages | filter: "weight" | map: "name" | join }}`, "a, c, d"},
-	// {"{{ \"a \n b\" | normalize_whitespace }}", "a b"},
+	{"{{ ws | normalize_whitespace }}", "a b c"},
 	{`{{ "123" | to_integer | type }}`, "int"},
 	{`{{ false | to_integer }}`, "0"},
 	{`{{ true | to_integer }}`, "1"},
 	{`{{ "here are some words" | number_of_words}}`, "4"},
+
+	{`{{ "The _config.yml file" | slugify }}`, "the-config-yml-file"},
+	{`{{ "The _config.yml file" | slugify: 'none' }}`, "the _config.yml file"},
+	{`{{ "The _config.yml file" | slugify: 'raw' }}`, "the-_config.yml-file"},
+	{`{{ "The _config.yml file" | slugify: 'default' }}`, "the-config-yml-file"},
+	{`{{ "The _config.yml file" | slugify: 'pretty' }}`, "the-_config.yml-file"},
+
 	{`{{ "1 < 2 & 3" | xml_escape }}`, "1 &lt; 2 &amp; 3"},
 	// {`{{ "http://foo.com/?q=foo, \bar?" | uri_escape }}`, "http://foo.com/?q=foo,%20%5Cbar?"},
 }
 
 var filterTestScope = map[string]interface{}{
 	"animals": []string{"zebra", "octopus", "giraffe", "Sally Snake"},
-	"ar":      []string{"first", "second", "third"},
+	"array":   []string{"first", "second", "third"},
 	"obj": map[string]interface{}{
 		"a": []int{1, 2, 3, 4},
 	},
@@ -82,6 +92,7 @@ var filterTestScope = map[string]interface{}{
 		},
 	},
 	"time": timeMustParse("2008-11-07T13:07:54Z"),
+	"ws":   "a  b\n\t c",
 }
 
 func timeMustParse(s string) time.Time {
@@ -93,6 +104,7 @@ func timeMustParse(s string) time.Time {
 }
 
 func TestFilters(t *testing.T) {
+	rand.Seed(1)
 	for i, test := range filterTests {
 		t.Run(fmt.Sprintf("%02d", i+1), func(t *testing.T) {
 			requireTemplateRender(t, test.in, filterTestScope, test.expected)