blob: f58dc47d5631c6f4bc192013085b98d98719e960 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
|
package dedent
import (
"regexp"
"strings"
)
var whitespaceOnly = regexp.MustCompile("(?m)^[ \t]+$")
var leadingWhitespace = regexp.MustCompile("(?m)(^[ \t]*)")
// Dedent removes any common leading whitespace from every line in s.
//
// This can be used to make multiline strings to line up with the left edge of
// the display, while still presenting them in the source code in indented
// form.
func Dedent(s string) string {
s = whitespaceOnly.ReplaceAllString(s, "")
margin := findMargin(s)
if len(margin) == 0 {
return s
}
return regexp.MustCompile("(?m)^"+margin).ReplaceAllString(s, "")
}
// Look for the longest leading string of spaces and tabs common to all lines.
func findMargin(s string) string {
var margin string
indents := leadingWhitespace.FindAllString(s, -1)
numIndents := len(indents)
for i, indent := range indents {
// Don't use last row if it is empty
if i == numIndents-1 && indent == "" {
break
}
if margin == "" {
margin = indent
} else if strings.HasPrefix(indent, margin) {
// Current line more deeply indented than previous winner:
// no change (previous winner is still on top).
continue
} else if strings.HasPrefix(margin, indent) {
// Current line consistent with and no deeper than previous winner:
// it's the new winner.
margin = indent
} else {
// Current line and previous winner have no common whitespace:
// there is no margin.
margin = ""
break
}
}
return margin
}
|
