Golang Simple Eval string

example.go

EvalStr("[a]Hello is not empty![/a] Print: {a} {b} [c]Hidden c[/c] [c][a] c and a [/a][/c] [b][a] b and a [/a][/b]",map[string]string{"a":"Hello","b":"World","c":""})

// out: Hello is not empty! Print: Hello World  b and a

GolangSimpleEval.go

func EvalStr(str string, input map[string]string) string {
	for key := range input {
		re := regexp.MustCompile(`(?mU)\[` + key + `\](.*)\[/` + key + `\]`)
		for _, match := range re.FindAllString(str, -1) {
			if len(input[key]) > 0 {
				inner := strings.Replace(match, `[`+key+`]`, "", -1)
				inner = strings.Replace(inner, `[/`+key+`]`, "", -1)
				str = strings.Replace(str, match, inner, -1)
			} else {
				str = strings.Replace(str, match, "", 1)
			}
		}
		str = strings.Replace(str, "{"+key+"}", input[key], -1)
	}

	// Replace not defined
	re := regexp.MustCompile(`(?m)\[(.*?)\](.*)\[/(.*?)\]`)
	for _, match := range re.FindAllString(str, -1) {
		str = strings.Replace(str, match, "", 1)
	}
	re = regexp.MustCompile(`(?mU)\{(.*?)\}`)
	for _, match := range re.FindAllString(str, -1) {
		str = strings.Replace(str, match, "", 1)
	}

	return str
}

[key] condition [/key]

{key} print value