More expansions in template repositories (#10021)

* Super expansion
* Explain which features are in 1.11 vs 1.12
* Move imports

Signed-off-by: jolheiser <john.olheiser@gmail.com>

vendor/github.com/huandu/xstrings/manipulate.go

@@ -0,0 +1,217 @@
+// Copyright 2015 Huan Du. All rights reserved.
+// Licensed under the MIT license that can be found in the LICENSE file.
+
+package xstrings
+
+import (
+	"bytes"
+	"strings"
+	"unicode/utf8"
+)
+
+// Reverse a utf8 encoded string.
+func Reverse(str string) string {
+	var size int
+
+	tail := len(str)
+	buf := make([]byte, tail)
+	s := buf
+
+	for len(str) > 0 {
+		_, size = utf8.DecodeRuneInString(str)
+		tail -= size
+		s = append(s[:tail], []byte(str[:size])...)
+		str = str[size:]
+	}
+
+	return string(buf)
+}
+
+// Slice a string by rune.
+//
+// Start must satisfy 0 <= start <= rune length.
+//
+// End can be positive, zero or negative.
+// If end >= 0, start and end must satisfy start <= end <= rune length.
+// If end < 0, it means slice to the end of string.
+//
+// Otherwise, Slice will panic as out of range.
+func Slice(str string, start, end int) string {
+	var size, startPos, endPos int
+
+	origin := str
+
+	if start < 0 || end > len(str) || (end >= 0 && start > end) {
+		panic("out of range")
+	}
+
+	if end >= 0 {
+		end -= start
+	}
+
+	for start > 0 && len(str) > 0 {
+		_, size = utf8.DecodeRuneInString(str)
+		start--
+		startPos += size
+		str = str[size:]
+	}
+
+	if end < 0 {
+		return origin[startPos:]
+	}
+
+	endPos = startPos
+
+	for end > 0 && len(str) > 0 {
+		_, size = utf8.DecodeRuneInString(str)
+		end--
+		endPos += size
+		str = str[size:]
+	}
+
+	if len(str) == 0 && (start > 0 || end > 0) {
+		panic("out of range")
+	}
+
+	return origin[startPos:endPos]
+}
+
+// Partition splits a string by sep into three parts.
+// The return value is a slice of strings with head, match and tail.
+//
+// If str contains sep, for example "hello" and "l", Partition returns
+//     "he", "l", "lo"
+//
+// If str doesn't contain sep, for example "hello" and "x", Partition returns
+//     "hello", "", ""
+func Partition(str, sep string) (head, match, tail string) {
+	index := strings.Index(str, sep)
+
+	if index == -1 {
+		head = str
+		return
+	}
+
+	head = str[:index]
+	match = str[index : index+len(sep)]
+	tail = str[index+len(sep):]
+	return
+}
+
+// LastPartition splits a string by last instance of sep into three parts.
+// The return value is a slice of strings with head, match and tail.
+//
+// If str contains sep, for example "hello" and "l", LastPartition returns
+//     "hel", "l", "o"
+//
+// If str doesn't contain sep, for example "hello" and "x", LastPartition returns
+//     "", "", "hello"
+func LastPartition(str, sep string) (head, match, tail string) {
+	index := strings.LastIndex(str, sep)
+
+	if index == -1 {
+		tail = str
+		return
+	}
+
+	head = str[:index]
+	match = str[index : index+len(sep)]
+	tail = str[index+len(sep):]
+	return
+}
+
+// Insert src into dst at given rune index.
+// Index is counted by runes instead of bytes.
+//
+// If index is out of range of dst, panic with out of range.
+func Insert(dst, src string, index int) string {
+	return Slice(dst, 0, index) + src + Slice(dst, index, -1)
+}
+
+// Scrub scrubs invalid utf8 bytes with repl string.
+// Adjacent invalid bytes are replaced only once.
+func Scrub(str, repl string) string {
+	var buf *bytes.Buffer
+	var r rune
+	var size, pos int
+	var hasError bool
+
+	origin := str
+
+	for len(str) > 0 {
+		r, size = utf8.DecodeRuneInString(str)
+
+		if r == utf8.RuneError {
+			if !hasError {
+				if buf == nil {
+					buf = &bytes.Buffer{}
+				}
+
+				buf.WriteString(origin[:pos])
+				hasError = true
+			}
+		} else if hasError {
+			hasError = false
+			buf.WriteString(repl)
+
+			origin = origin[pos:]
+			pos = 0
+		}
+
+		pos += size
+		str = str[size:]
+	}
+
+	if buf != nil {
+		buf.WriteString(origin)
+		return buf.String()
+	}
+
+	// No invalid byte.
+	return origin
+}
+
+// WordSplit splits a string into words. Returns a slice of words.
+// If there is no word in a string, return nil.
+//
+// Word is defined as a locale dependent string containing alphabetic characters,
+// which may also contain but not start with `'` and `-` characters.
+func WordSplit(str string) []string {
+	var word string
+	var words []string
+	var r rune
+	var size, pos int
+
+	inWord := false
+
+	for len(str) > 0 {
+		r, size = utf8.DecodeRuneInString(str)
+
+		switch {
+		case isAlphabet(r):
+			if !inWord {
+				inWord = true
+				word = str
+				pos = 0
+			}
+
+		case inWord && (r == '\'' || r == '-'):
+			// Still in word.
+
+		default:
+			if inWord {
+				inWord = false
+				words = append(words, word[:pos])
+			}
+		}
+
+		pos += size
+		str = str[size:]
+	}
+
+	if inWord {
+		words = append(words, word[:pos])
+	}
+
+	return words
+}