added util module

util/util.go

@@ -0,0 +1,50 @@
+package util
+
+import "regexp"
+
+// RegexpSplit split slices s into substrings separated by the expression and
+// returns a slice of the substrings between those expression matches.
+// If capturing parentheses are used in expression, then the text of all groups
+// in the expression are also returned as part of the resulting slice.
+//
+// This function acts consistent with Python's re.split function.
+func RegexpSplit(re *regexp.Regexp, s string, n int) []string {
+	if n == 0 {
+		return nil
+	}
+
+	if len(re.String()) > 0 && len(s) == 0 {
+		return []string{""}
+	}
+
+	var matches [][]int
+	if len(re.SubexpNames()) > 1 {
+		matches = re.FindAllStringSubmatchIndex(s, n)
+	} else {
+		matches = re.FindAllStringIndex(s, n)
+	}
+	strings := make([]string, 0, len(matches))
+
+	beg := 0
+	end := 0
+	for _, match := range matches {
+		if n > 0 && len(strings) >= n-1 {
+			break
+		}
+
+		end = match[0]
+		if match[1] != 0 {
+			strings = append(strings, s[beg:end])
+		}
+		beg = match[1]
+		if len(re.SubexpNames()) > 1 {
+			strings = append(strings, s[match[0]:match[1]])
+		}
+	}
+
+	if end != len(s) {
+		strings = append(strings, s[beg:])
+	}
+
+	return strings
+}