Add SQL function string.slug

sql/funcs.go

@@ -166,6 +166,7 @@ var funcs = map[string]map[int]interface{}{
 	"string.reverse":    {1: nil},
 	"string.search":     {2: nil},
 	"string.slice":      {3: nil},
+	"string.slug":       {1: nil, 2: nil},
 	"string.split":      {2: nil},
 	"string.startsWith": {2: nil},
 	"string.substr":     {3: nil},

util/fncs/fnc.go

@@ -198,6 +198,8 @@ func Run(ctx context.Context, name string, args ...interface{}) (interface{}, er
 		return stringSearch(ctx, args...)
 	case "string.slice":
 		return stringSlice(ctx, args...)
+	case "string.slug":
+		return stringSlug(ctx, args...)
 	case "string.split":
 		return stringSplit(ctx, args...)
 	case "string.startsWith":

util/fncs/string.go

@@ -20,6 +20,7 @@ import (
 	"strings"
 
 	"github.com/abcum/surreal/util/ints"
+	"github.com/abcum/surreal/util/slug"
 	"github.com/abcum/surreal/util/text"
 )
 
@@ -138,6 +139,19 @@ func stringSlice(ctx context.Context, args ...interface{}) (interface{}, error)
 	return s, nil
 }
 
+func stringSlug(ctx context.Context, args ...interface{}) (interface{}, error) {
+	switch len(args) {
+	case 1:
+		s, _ := ensureString(args[0])
+		return slug.Make(s), nil
+	case 2:
+		s, _ := ensureString(args[0])
+		l, _ := ensureString(args[1])
+		return slug.MakeLang(s, l), nil
+	}
+	return nil, nil
+}
+
 func stringSplit(ctx context.Context, args ...interface{}) (interface{}, error) {
 	s, _ := ensureString(args[0])
 	p, _ := ensureString(args[1])

util/slug/lang.go

@@ -0,0 +1,76 @@
+// Copyright © 2016 Abcum Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package slug
+
+func init() {
+	// Merge language subs with the default one
+	for _, sub := range []*map[rune]string{&en, &de, &fr, &es, &nl, &pl, &gr} {
+		for key, value := range defaults {
+			(*sub)[key] = value
+		}
+	}
+}
+
+var defaults = map[rune]string{
+	'"':  "",
+	'\'': "",
+	'’':  "",
+	'‒':  "-", // figure dash
+	'–':  "-", // en dash
+	'—':  "-", // em dash
+	'―':  "-", // horizontal bar
+}
+
+var en = map[rune]string{
+	'&': "and",
+	'@': "at",
+}
+
+var de = map[rune]string{
+	'&': "und",
+	'@': "an",
+}
+
+var fr = map[rune]string{
+	'&': "et",
+	'@': "a",
+}
+
+var es = map[rune]string{
+	'&': "y",
+	'@': "en",
+}
+
+var nl = map[rune]string{
+	'&': "en",
+	'@': "at",
+}
+
+var pl = map[rune]string{
+	'&': "i",
+	'@': "na",
+}
+
+var gr = map[rune]string{
+	'&': "kai",
+	'η': "i",
+	'ή': "i",
+	'Η': "i",
+	'ι': "i",
+	'ί': "i",
+	'Ι': "i",
+	'χ': "x",
+	'Χ': "x",
+}

util/slug/slug.go

@@ -0,0 +1,84 @@
+// Copyright © 2016 Abcum Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package slug
+
+import (
+	"bytes"
+	"regexp"
+	"strings"
+
+	"github.com/rainycape/unidecode"
+)
+
+var (
+	regexpUnicode = regexp.MustCompile("[^a-z0-9-_]")
+	regexpHyphens = regexp.MustCompile("-+")
+)
+
+func Make(s string) (slug string) {
+	return MakeLang(s, "en")
+}
+
+func MakeLang(s string, l string) (slug string) {
+
+	slug = strings.TrimSpace(s)
+
+	switch l {
+	case "de":
+		slug = substitute(slug, de)
+	case "en":
+		slug = substitute(slug, en)
+	case "pl":
+		slug = substitute(slug, pl)
+	case "es":
+		slug = substitute(slug, es)
+	case "gr":
+		slug = substitute(slug, gr)
+	case "nl":
+		slug = substitute(slug, nl)
+	default:
+		slug = substitute(slug, en)
+	}
+
+	// Process all non ASCII symbols
+	slug = unidecode.Unidecode(slug)
+
+	// Format the text as lower case
+	slug = strings.ToLower(slug)
+
+	// Process remaining symbols
+	slug = regexpUnicode.ReplaceAllString(slug, "-")
+
+	// Process duplicated hyphens
+	slug = regexpHyphens.ReplaceAllString(slug, "-")
+
+	// Trim leading hyphens
+	slug = strings.Trim(slug, "-")
+
+	return slug
+
+}
+
+func substitute(s string, sub map[rune]string) string {
+	var buf bytes.Buffer
+	for _, c := range s {
+		if d, ok := sub[c]; ok {
+			buf.WriteString(d)
+		} else {
+			buf.WriteRune(c)
+		}
+	}
+	return buf.String()
+}