proc `$`(rune: Rune): string {.inline, ...raises: [CatchableError], tags: [],
                               forbids: [].}

proc `$`(runes: seq[Rune]): string {....raises: [CatchableError], tags: [],
                                     forbids: [].}

proc add(s: var string; rune: Rune) {....raises: [CatchableError], tags: [],
                                      forbids: [].}

proc containsControlCharacter(s: openArray[char]): bool {....raises: [], tags: [],
    forbids: [].}

proc find(s: openArray[char]; needle: char; start = 0; last = -1): int {.
    ...raises: [], tags: [], forbids: [].}

proc find(s: openArray[char]; needle: string; start = 0; last = -1): int {.
    ...raises: [], tags: [], forbids: [].}

proc runeAt(s: openArray[char]; i: int): Rune {....raises: [CatchableError],
    tags: [], forbids: [].}

proc size(rune: Rune): int {....raises: [CatchableError], tags: [], forbids: [].}

proc toUTF8(rune: Rune): string {.inline, ...raises: [CatchableError], tags: [],
                                  forbids: [].}

proc truncateUtf8(s: openArray[char]; maxBytes: int): string {.
    ...raises: [CatchableError], tags: [], forbids: [].}

proc unsafeAdd(s: var string; rune: Rune) {....raises: [], tags: [], forbids: [].}

proc validateUtf8(s: openArray[char]): int {....raises: [], tags: [], forbids: [].}

proc validRuneAt(s: openArray[char]; i: int): Option[Rune] {....raises: [],
    tags: [], forbids: [].}

template `==`(a, b: Rune): bool

template isHighSurrogate(rune: Rune): bool

template isLowSurrogate(rune: Rune): bool

template isSurrogate(rune: Rune): bool

template isValid(rune: Rune): bool

template unsafeSize(rune: Rune): int