camelcase.go

package main

func camelCase(s string) string {
	s = strings.TrimSpace(s)
	buffer := make([]rune, 0, len(s))

	var prev rune
	for _, curr := range s {
		if !isDelimiter(curr) {
			if isDelimiter(prev) || (prev == 0) {
				buffer = append(buffer, toUpper(curr))
			} else {
				buffer = append(buffer, toLower(curr))
			}
		}
		prev = curr
	}

	return string(buffer)
}

func isDelimiter(ch rune) bool {
	return ch == '-' || ch == '_' || isSpace(ch)
}

func toUpper(ch rune) rune {
	if ch >= 'a' && ch <= 'z' {
		return ch - 32
	}
	return ch
}

func toLower(ch rune) rune {
	if ch >= 'A' && ch <= 'Z' {
		return ch + 32
	}
	return ch
}

func isSpace(ch rune) bool {
	return ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r'
}