Reference Swift implementation of Rangeable<Element> — a generic, integer-coordinate, closed-interval set container with first-insert ordered active queries.

Installation

Swift Package Manager

In your Package.swift:

dependencies: [
    .package(url: "https://github.com/ZhgChgLi/SwiftRangeable.git", from: "1.0.0"),
],
targets: [
    .target(name: "YourTarget", dependencies: ["Rangeable"]),
]

Or add the package via Xcode → File → Add Packages → paste the repository URL.

Usage

import Rangeable

enum InlineMarkup: Hashable, RangeableElement {
    case strong
    case italic
    case link(String)
}

var r = Rangeable<InlineMarkup>()
try r.insert(.strong,        start: 2, end: 5)
try r.insert(.strong,        start: 3, end: 7)   // merges with [2, 5] → [2, 7]
try r.insert(.strong,        start: 9, end: 11)  // disjoint
try r.insert(.italic,        start: 3, end: 8)

r.getRange(of: .strong)   // [Interval(lo: 2, hi: 7), Interval(lo: 9, hi: 11)]
r.getRange(of: .italic)   // [Interval(lo: 3, hi: 8)]

r[4].objs    // [.strong, .italic]   first-insert order
r[8].objs    // [.italic]
r[10].objs   // [.strong]

Sweep iteration via transitions

let events = r.transitions(over: 0...15)
for event in events {
    switch event.kind {
    case .open:
        print("\(event.coordinate ?? Int.max): open \(event.element)")
    case .close:
        print("\(event.coordinate ?? Int.max): close \(event.element)")
    }
}

API

Member	Type	Notes
Rangeable<Element>()	initializer	empty
mutating func insert(_:start:end:) throws	mutates self	throws RangeableError.invalidInterval if start > end
subscript(_ i: Int)	Slot<Element>	exposes .objs
getRange(of:)	[Interval]	merged disjoint ranges
transitions(over:)	[TransitionEvent<Element>]	accepts ClosedRange<Int>
count	Int	distinct elements
isEmpty	Bool
iteration	Sequence conformance	for (element, ranges) in r

Semantics

• End is inclusive: [a, b] covers a...b, both ends.
• Same-element merging: equal elements (by Hashable) merge on overlap or integer adjacency. [2, 4] ∪ [5, 7] = [2, 7].
• Idempotent insert: re-inserting a contained interval costs no version bump.
• Out-of-order rejected: try insert(_, start: 5, end: 2) throws.
• Active-set ordering: deterministic — first-insert order of the element.
• Coordinate sentinel: a close event for an interval ending at Int.max carries coordinate == nil (None == +∞ per RFC § 4.7).
• Value semantics + COW: Rangeable is a struct with copy-on-write storage; assignment is O(1).

See RangeableRFC § 4 for normative semantics and § 10 for the 23-case test contract.

Cross-language consistency

This Swift implementation joins the Ruby, Python, JS, Kotlin and Go implementations. All six share a 160-op / 86-probe JSON fixture and produce byte-identical outputs.

See also

• RangeableRFC — normative specification.
• RubyRangeable — Ruby reference (gem install rangeable).
• PythonRangeable — Python reference (pip install rangeable).
• JSRangeable — TypeScript reference (npm i rangeable-js).
• KotlinRangeable — Kotlin/JVM reference (JitPack).
• GoRangeable — Go reference (go get github.com/ZhgChgLi/GoRangeable).

Development

$ swift test

38 tests cover the full RFC § 10 contract, additional coverage for count / isEmpty / iteration / COW semantics, a property test against a brute-force oracle, and the cross-language fixture.

License

MIT © ZhgChgLi

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