2.1.0

No library changes — SPM consumers are unaffected.

The test suite (37 suites, 179 tests) is migrated from XCTest to Swift Testing: @Test functions with #expect/#require, value-type suites, per-test seeded RNGs, and parallel execution by default. Availability-gated suites (Zip) carry @available per test function, specific-error expectations use #expect(throws: SomeError.case), and the Sudoku validity helper threads sourceLocation so failures point at the calling test.

Validated on Swift 6.0.2 (macOS + Linux), the current Xcode toolchain, and the latest Swift Linux image.

2.0.0

A major release: critical correctness fixes, a rework of the library's concurrency
story, removal of APIs that didn't make sense, and a batch of new generators. If you are
coming from 1.x, build against 1.3.0 first — it deprecates everything 2.0 removes, with
messages naming the replacements.

Concurrency: RandomGenerator no longer requires Sendable

Generators are ordinary values, confined to the isolation domain where they are built
and run:

• The protocol requires neither Sendable nor Element: Sendable. Conformers may hold
  non-Sendable state and produce non-Sendable values.
• Transform closures (map, flatMap, filter, retry, tryMap, ...) are plain
  closures — they can capture anything the surrounding context can.
• Leaf generators (IntGenerator, FloatGenerator, BoolGenerator, Always,
  Character, UnicodeScalar, the seeded RNGs, and all ready-made generators) declare
  Sendable explicitly, and closure-free combinators (Array, Collect, Concat,
  Dictionary, Element, Frequency, OneOf, OrNil, Print, Shuffled, Tuple,
  Zip, ...) propagate it conditionally — so leaf-only compositions remain shareable.
• RemoveDuplicates drops its lock and @unchecked Sendable; the compiler now enforces
  its single-domain confinement.
• AttemptBounded.FallbackStrategy is no longer Sendable (it carries a closure).

Migration: pipelines containing closures are no longer Sendable. Move one into a
Task and region isolation checks the transfer; to use a pipeline from several tasks,
build one per task.

Fixed

• AnyRandomGenerator never advanced the caller's RNG — erased generators (including
  the character presets) replayed the same value forever under a seeded RNG. Seeded
  sequences involving erased generators change with this fix.
• Zip(...).map { a, b, c in } compiles again on Swift 6.3 via a pack-argument overload.
• compactMap/retryMap could crash on a force-unwrap when the attempt budget was
  exhausted; they now produce Optional (nil on exhaustion). retryThrowing produces
  Result (the last failure on exhaustion), runs its transform once per candidate, and
  no longer backstops with fatalError.
• uiColor(alpha:)/swiftUIColor(alpha:) silently ignored their alpha parameter; the
  parameter is removed and the generator's init(alpha:) visibly governs.
• UnicodeScalar/Character generation over ranges spanning the surrogate gap
  (U+D800–DFFF) no longer biases toward the lower bound or traps; the gap is skipped
  uniformly.
• Frequency no longer materializes a sum-of-all-weights array on every run (cumulative
  bounds + one draw), and fails fast with clear preconditions on empty or all-zero
  distributions.
• AttemptBounded counts the initial run toward maxAttempts (previously
  maxAttempts: 3 ran the upstream up to 4 times); maxAttempts must be ≥ 1.
• IntGenerator(in: 0..<0) traps with a clear message instead of a confusing
  ClosedRange precondition.
• The package declared iOS 13 but could not compile for iOS at all (Zip's parameter
  packs require the iOS 17 runtime). Platforms are now honestly declared —
  iOS 13 / macOS 10.15 / tvOS 13 / watchOS 6 — with only Zip and its operators gated
  behind @available(macOS 14, iOS 17, tvOS 17, watchOS 10).
• IPAddressGenerator imports Foundation explicitly.

Added

• RandomGenerators.Bernoulli / .bool(probability:) — biased coin.
• orNil(probability:) — produce nil with a given probability.
• RandomGenerators.Normal (Box–Muller) and RandomGenerators.Exponential
  distributions, with .normal(mean:standardDeviation:) / .exponential(rate:) sugar.
• RandomGenerators.oneOf(...) — uniform pick across 2–4 generators of different
  concrete types sharing an element type.
• RandomGenerators.string(of:count:) and characterGen.string(count:).
• Seeded RNGs: Xoshiro256 (xoshiro256++), SplitMix64, PCG (independent streams via
  sequence:).
• Dice(sides:) with d4/d6/d8/d10/d12/d20/d100 presets.
• Dot-syntax statics: .int(in:), .float(in:), .bool.
• RandomGenerators.sudoku(difficulty:) convenience.
• DocC catalogs for both modules and the swift-docc-plugin.
• A runnable example target exercising the whole API.

Changed (breaking)

• BoolRandomGenerator is renamed BoolGenerator (deprecated typealias retained).
• compactMap/retryMap produce Output?; retryThrowing produces
  Result<Output, Error>.
• Frequency is constructed via RandomGenerators.frequency(_:); the receiver-ignoring
  instance method is removed.
• UnicodeScalar and Character are standalone generators constructed from a range;
  the combinator forms (whose upstream was ignored) are removed.

Removed

• ZipArrayGenerator, zipAll(), zipGenerators(...) — exact duplicates of Collect;
  use [generators].collect().
• gen.always(_:), gen.colorGenerator(alpha:) — receiver-ignoring factories; construct
  Always(_:) / ColorGenerator(alpha:) directly.
• CreditCardGenerator.Generated — use Element.

1.3.0

The final planned release of the 1.x line. It backports the features and critical fixes
from the upcoming 2.0 and deprecates every API that 2.0 removes, so migrating is mostly
a matter of following compiler warnings.

Fixed

• AnyRandomGenerator never advanced the caller's RNG. Erased generators — including
  the built-in number, uppercaseLetter, lowercaseLetter and character(in:)
  presets — replayed the same value forever under a seeded RNG. Seeded sequences that
  involve erased generators will change with this fix; the first draw is unaffected.
• Zip(...).map { a, b, c in } failed to compile on Swift 6.3 (pack-expansion tuples are
  no longer destructured into multi-parameter closures). A map overload on Zip that
  receives the values as separate arguments restores the spelling, and CI now also builds
  with the current Xcode toolchain and the latest Swift Linux image.
• IPAddressGenerator imports Foundation explicitly (required under
  MemberImportVisibility).
• Shuffled no longer requires Element.Element: Equatable; shuffling never compares
  elements.

Added

• RandomGenerators.Bernoulli / .bool(probability:) — biased coin.
• orNil(probability:) — produce nil with a given probability.
• RandomGenerators.Normal (Box–Muller) and RandomGenerators.Exponential distribution
  generators, with .normal(mean:standardDeviation:) / .exponential(rate:) sugar.
• RandomGenerators.oneOf(...) — uniform pick across 2–4 generators of different
  concrete types sharing an element type.
• RandomGenerators.string(of:count:) and characterGen.string(count:) — build strings
  directly from a character generator.
• Seeded RNGs: Xoshiro256 (xoshiro256++), SplitMix64, and PCG (with independent
  streams via sequence:). LCRNG documents its statistical weakness and points
  simulations at these.
• RandomGenerators.frequency(_:) static factory (the 2.0 spelling).
• BoolGenerator typealias (the 2.0 name for BoolRandomGenerator).

Deprecated (removed in 2.0)

• ZipArrayGenerator, zipAll(), zipGenerators(...) → use [generators].collect().
• gen.always(_:) → construct Always(_:) directly (the receiver was ignored).
• gen.colorGenerator(alpha:) → construct ColorGenerator(alpha:) directly.
• gen.frequency(_:) → RandomGenerators.frequency(_:) (the receiver was never part of
  the distribution).
• gen.character(in:) / gen.unicodeScalar(in:) → RandomGenerators.character(in:)
  (the upstream generator was ignored).
• uiColor(alpha:using:) / swiftUIColor(alpha:using:) → uiColor(using:) /
  swiftUIColor(using:) (the alpha parameter was silently ignored; set alpha at
  initialization).
• CreditCardGenerator.Generated → Element.

1.2.0

What's Changed

• Add Several improvements by @ibrahimkteish in #13

Full Changelog: 1.1.0...1.2.0

1.1.0

What's Changed

• Make RandomGenerator Sendable by @ibrahimkteish in #11
• v1.1.0 by @ibrahimkteish in #12

Full Changelog: 1.0.0...1.1.0

1.0.0

Full Changelog: 1.0.0...1.0.0