clifmt/internal/transform/markdown/underline.go

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1022 B
Go
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package markdown
import (
"fmt"
"regexp"
"strings"
)
var underlineRe = regexp.MustCompile(`(?m)_([^_]+)_`)
// underline returns the terminal-formatted underline text @t
func underline(t string) string {
return fmt.Sprintf("\x1b[4m%s\x1b[24m", strings.Replace(t, "\x1b[0m", "\x1b[0m\x1b[4m", -1))
}
// underlineTransform the @input text using markdown-like syntax :
// - "normal _underline_ normal"
func underlineTransform(input string) (string, error) {
output := ""
cursor := int(0)
// 1. Replace for each match
for _, match := range underlineRe.FindAllStringSubmatchIndex(input, -1) {
// (1) add gap between input start OR previous match
output += input[cursor:match[0]]
cursor = match[1]
// (2) extract features
text := ""
if match[3]-match[2] > 0 {
text = input[match[2]:match[3]]
}
// (3) replace text with bold text
output += underline(text)
}
// 2. Add end of input
if cursor < len(input)-1 {
output += input[cursor:]
}
// 3. print final output
return output, nil
}