update

utils/index_group_parser.go

@@ -0,0 +1,38 @@
+package utils
+
+import (
+	"regexp"
+	"strings"
+)
+
+type IndexGroups map[string]string
+
+// ParseIndexGroups
+// The specification is a space-separated list of index entries. Normally, each entry is just a single character,
+// but you may also specify multiple characters.  For instance, the entry "The" will link to all files and
+// folders starting with "The".
+//
+// You may also create an entry using a group of index characters in parentheses. For instance, the entry
+// "A-E(ABCDE)" will display as "A-E" and link to all files and folders starting with either
+// A, B, C, D or E.  This may be useful for grouping less-frequently used characters (such and X, Y and Z), or
+// for grouping accented characters (such as A, \u00C0 and \u00C1)
+//
+// Files and folders that are not covered by an index entry will be placed under the index entry "#".
+
+var indexGroupsRx = regexp.MustCompile(`(.+)\((.+)\)`)
+
+func ParseIndexGroups(spec string) IndexGroups {
+	parsed := make(IndexGroups)
+	split := strings.Split(spec, " ")
+	for _, g := range split {
+		sub := indexGroupsRx.FindStringSubmatch(g)
+		if len(sub) > 0 {
+			for _, c := range sub[2] {
+				parsed[string(c)] = sub[1]
+			}
+		} else {
+			parsed[g] = g
+		}
+	}
+	return parsed
+}