Method parseEscape

parser.go:21–57

parseEscape parses a backslash escape.

()

// parseEscape parses a backslash escape.
func (p *parser) parseEscape() (result string, err error) {
	if len(p.s) < p.i+2 || p.s[p.i] != '\\' {
		return "", errors.New("invalid escape sequence")
	}

	start := p.i + 1
	c := p.s[start]
	switch {
	case c == '\r' || c == '\n' || c == '\f':
		return "", errors.New("escaped line ending outside string")
	case hexDigit(c):
		// unicode escape (hex)
		var i int
		for i = start; i < p.i+6 && i < len(p.s) && hexDigit(p.s[i]); i++ {
			// empty
		}
		v, _ := strconv.ParseUint(p.s[start:i], 16, 21)
		if len(p.s) > i {
			switch p.s[i] {
			case '\r':
				i++
				if len(p.s) > i && p.s[i] == '\n' {
					i++
				}
			case ' ', '\t', '\n', '\f':
				i++
			}
		}
		p.i = i
		return string(rune(v)), nil
	}

	// Return the literal character after the backslash.
	result = p.s[start : start+1]
	p.i += 2
	return result, nil
}

func hexDigit(c byte) bool {
	return '0' <= c && c <= '9' || 'a' <= c && c <= 'f' || 'A' <= c && c <= 'F'