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// Copyright (c) 2014-2019 TSUYUSATO Kitsune
// This software is released under the MIT License.
// http://opensource.org/licenses/mit-license.php
// Package heredoc provides creation of here-documents from raw strings.
//
// Golang supports raw-string syntax.
//
// doc := `
// Foo
// Bar
// `
//
// But raw-string cannot recognize indentation. Thus such content is an indented string, equivalent to
//
// "\n\tFoo\n\tBar\n"
//
// I dont't want this!
//
// However this problem is solved by package heredoc.
//
// doc := heredoc.Doc(`
// Foo
// Bar
// `)
//
// Is equivalent to
//
// "Foo\nBar\n"
package heredoc
import (
"fmt"
"strings"
"unicode"
)
const maxInt = int(^uint(0) >> 1)
// Doc returns un-indented string as here-document.
func Doc(raw string) string {
skipFirstLine := false
if len(raw) > 0 && raw[0] == '\n' {
raw = raw[1:]
} else {
skipFirstLine = true
}
lines := strings.Split(raw, "\n")
minIndentSize := getMinIndent(lines, skipFirstLine)
lines = removeIndentation(lines, minIndentSize, skipFirstLine)
return strings.Join(lines, "\n")
}
// getMinIndent calculates the minimum indentation in lines, excluding empty lines.
func getMinIndent(lines []string, skipFirstLine bool) int {
minIndentSize := maxInt
for i, line := range lines {
if i == 0 && skipFirstLine {
continue
}
indentSize := 0
for _, r := range []rune(line) {
if unicode.IsSpace(r) {
indentSize += 1
} else {
break
}
}
if len(line) == indentSize {
if i == len(lines)-1 && indentSize < minIndentSize {
lines[i] = ""
}
} else if indentSize < minIndentSize {
minIndentSize = indentSize
}
}
return minIndentSize
}
// removeIndentation removes n characters from the front of each line in lines.
// Skips first line if skipFirstLine is true, skips empty lines.
func removeIndentation(lines []string, n int, skipFirstLine bool) []string {
for i, line := range lines {
if i == 0 && skipFirstLine {
continue
}
if len(lines[i]) >= n {
lines[i] = line[n:]
}
}
return lines
}
// Docf returns unindented and formatted string as here-document.
// Formatting is done as for fmt.Printf().
func Docf(raw string, args ...interface{}) string {
return fmt.Sprintf(Doc(raw), args...)
}
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