tokenizeDottedString.kt

/**
 * Transform the given dotted string [str] to a sequence of string.
 * Example: `"key.value"` -> `["key", "value"]`
 *
 * - All values are trimmed of whitespaces. `" a. b .c "` -> `["a", "b", "c"]`
 * - An empty point `"."`, multiple points `".."` produces nothing. -> `[]`
 * - Leading point(s) `".key"`, `"..key"` or trailing point(s) `"key."`, `"key.."` are omitted -> `["key"]`
 * - Multipoint between elements  `"key..value"` are like single point -> `["key", "value"]`
 *
 * @param str The dotted string to parse
 * @return A sequence of trimmed strings separated by dots.
 */
@Suppress("NOTHING_TO_INLINE")
internal inline fun tokenizeDottedString(str: CharSequence): Sequence<String> = sequence {
    if(str.isEmpty()) return@sequence

    var index = 0

    // dismiss empty accessor
    while(index < str.length && (str[index] == '.' || str[index].isWhitespace())) index += 1
    if(index == str.length) return@sequence

    var wordStart: Int = -1
    var wordEnd = 0

    while (index < str.length) {
        if(str[index] == '.') {
            if(wordStart != -1) yield(str.substring(wordStart, wordEnd))
            wordStart = -1
        } else if(!str[index].isWhitespace()) {
            if(wordStart == -1) wordStart = index
            wordEnd = index + 1
        }
        index++
    }
    if(wordStart != -1) yield(str.substring(wordStart, wordEnd))
}