CharSequence.indicesOf.kt

fun CharSequence.indicesOf(pattern: String): Sequence<Int> = sequence {
    var startIndex = 0
    while (true) {
        startIndex = indexOf(pattern, startIndex)
        if (startIndex < 0) break
        yield(startIndex)
        startIndex += pattern.length
    }
}

fun CharSequence.matches(pattern: String): Sequence<IntRange> =
        indicesOf(pattern).map { it until it + pattern.length }