Method parseRegex

parser.go:197–227

parseRegex parses a regular expression; the end is defined by encountering an unmatched closing ')' or ']' which is not consumed

()

// parseRegex parses a regular expression; the end is defined by encountering an
// unmatched closing ')' or ']' which is not consumed
func (p *parser) parseRegex() (rx *regexp.Regexp, err error) {
	i := p.i
	if len(p.s) < i+2 {
		return nil, errors.New("expected regular expression, found EOF instead")
	}

	// number of open parens or brackets;
	// when it becomes negative, finished parsing regex
	open := 0

loop:
	for i < len(p.s) {
		switch p.s[i] {
		case '(', '[':
			open++
		case ')', ']':
			open--
			if open < 0 {
				break loop
			}
		}
		i++
	}

	if i >= len(p.s) {
		return nil, errors.New("EOF in regular expression")
	}
	rx, err = regexp.Compile(p.s[p.i:i])
	p.i = i
	return rx, err
}

// skipWhitespace consumes whitespace characters and comments.
// It returns true if there was actually anything to skip.