Module ropes

This module contains support for a rope data type. Ropes can represent very long strings efficiently; especially concatenation is done in O(1) instead of O(n). They are essentially concatenation trees that are only flattened when converting to a native Nim string. The empty string is represented by nil. Ropes are immutable and subtrees can be shared without copying. Leaves can be cached for better memory efficiency at the cost of runtime efficiency.

Types

Rope = ref RopeObj

empty rope is represented by nil

Procs

proc len(a: Rope): int {.gcsafe, extern: "nro$1", raises: [], tags: [].}

the rope's length

proc rope(s: string): Rope {.gcsafe, extern: "nro$1Str", raises: [], tags: [].}

Converts a string to a rope.

proc rope(i: BiggestInt): Rope {.gcsafe, extern: "nro$1BiggestInt", raises: [], tags: [].}

Converts an int to a rope.

proc rope(f: BiggestFloat): Rope {.gcsafe, extern: "nro$1BiggestFloat", raises: [],
                               tags: [].}

Converts a float to a rope.

proc enableCache() {.gcsafe, extern: "nro$1", raises: [], tags: [].}

Enables the caching of leaves. This reduces the memory footprint at the cost of runtime efficiency.

proc disableCache() {.gcsafe, extern: "nro$1", raises: [], tags: [].}

the cache is discarded and disabled. The GC will reuse its used memory.

proc `&`(a, b: Rope): Rope {.gcsafe, extern: "nroConcRopeRope", raises: [], tags: [].}

the concatenation operator for ropes.

proc `&`(a: Rope; b: string): Rope {.gcsafe, extern: "nroConcRopeStr", raises: [], tags: [].}

the concatenation operator for ropes.

proc `&`(a: string; b: Rope): Rope {.gcsafe, extern: "nroConcStrRope", raises: [], tags: [].}

the concatenation operator for ropes.

proc `&`(a: openArray[Rope]): Rope {.gcsafe, extern: "nroConcOpenArray", raises: [],
                                 tags: [].}

the concatenation operator for an openarray of ropes.

proc add(a: var Rope; b: Rope) {.gcsafe, extern: "nro$1Rope", raises: [], tags: [].}

adds b to the rope a.

proc add(a: var Rope; b: string) {.gcsafe, extern: "nro$1Str", raises: [], tags: [].}

adds b to the rope a.

proc `[]`(r: Rope; i: int): char {.gcsafe, extern: "nroCharAt", raises: [], tags: [].}

returns the character at position i in the rope r. This is quite expensive! Worst-case: O(n). If i >= r.len, \0 is returned.

proc write(f: File; r: Rope) {.gcsafe, extern: "nro$1", raises: [IOError],
                          tags: [WriteIOEffect].}

writes a rope to a file.

proc `$`(r: Rope): string {.gcsafe, extern: "nroToString", raises: [], tags: [].}

converts a rope back to a string.

proc `%`(frmt: string; args: openArray[Rope]): Rope {.gcsafe, extern: "nroFormat",
    raises: [ValueError], tags: [].}

% substitution operator for ropes. Does not support the $identifier nor ${identifier} notations.

proc addf(c: var Rope; frmt: string; args: openArray[Rope]) {.gcsafe, extern: "nro$1",
    raises: [ValueError], tags: [].}

shortcut for add(c, frmt % args).

proc equalsFile(r: Rope; f: File): bool {.gcsafe, extern: "nro$1File", raises: [IOError],
                                    tags: [ReadIOEffect].}

returns true if the contents of the file f equal r.

proc equalsFile(r: Rope; filename: string): bool {.gcsafe, extern: "nro$1Str",
    raises: [IOError], tags: [ReadIOEffect].}

returns true if the contents of the file f equal r. If f does not exist, false is returned.

Iterators

iterator leaves(r: Rope): string {.raises: [], tags: [].}

iterates over any leaf string in the rope r.

iterator items(r: Rope): char {.raises: [], tags: [].}

iterates over any character in the rope r.