Typed throws, cached regexes, ISO8601FormatStyle, Swift 6.4 CI

.github/workflows/ci.yml

@@ -2,16 +2,14 @@
 #
 # Category A (tools-version 6.2 + macOS 26 min): macos-26 + Swift 6.2
 # Category B (tools-version 6.2 + older macOS):  macos-15 + 6.2, macos-26 + 6.2
-# Category C (tools-version 6.3):                macos-15 + 6.3, macos-26 + 6.3
-# Linux:                                          ubuntu + Swift 6.3
+# Category C (tools-version 6.3):                macos-15 + 6.3/6.4, macos-26 + 6.3/6.4
+# Linux:                                          ubuntu + Swift 6.3/6.4
 #   (Package.swift excludes METARFormatting/DecodeMETAR/DecodeTAF on Linux — they format
 #   Measurement values via APIs swift-corelibs-foundation doesn't implement; SwiftMETAR
 #   core + DecodeWindsAloft + tests are unaffected and build/test on Linux normally)
 #
 # This package is Category C. BuildableMacro requires tools-version 6.3, so Swift
 # 6.1 and 6.2 can no longer resolve it.
-#
-# When Swift 6.4 ships: add 6.4 legs alongside 6.3
 
 name: CI
 
@@ -34,10 +32,16 @@ jobs:
         include:
           - os: macos-15
             swift: "6.3"
+          - os: macos-15
+            swift: "6.4"
           - os: macos-26
             swift: "6.3"
+          - os: macos-26
+            swift: "6.4"
           - os: ubuntu-latest
             swift: "6.3"
+          - os: ubuntu-latest
+            swift: "6.4"
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v6

CHANGELOG.md

@@ -1,5 +1,21 @@
 # Change Log
 
+## [Unreleased]
+
+### Changed
+
+- Every throwing API now declares its error type: `throws(Error)` replaces
+  untyped `throws` across the parsers and on public entry points such as
+  `METAR.from(string:on:)`, `TAF.from(string:on:)`, and
+  `CodedRepresentable.init(coded:)`. Callers need no changes — `catch` blocks
+  that matched `SwiftMETAR.Error` keep working, and exhaustive `catch` over the
+  enum's cases is now possible without a fallback clause.
+- Case-set regexes (`Weather.Phenomenon`, `Remark.Coverage`, and the other
+  `RawRepresentable` code sets) are built with RegexBuilder and cached per type
+  instead of being assembled as a pattern string and recompiled on every access.
+- ISO 8601 timestamps in aviationweather.gov XML are parsed with
+  `Date.ISO8601FormatStyle` rather than `ISO8601DateFormatter`.
+
 ## [4.1.0] - 2026-09-14
 
 ### Changed

Package.swift

@@ -8,7 +8,8 @@ let upcomingFeatures: [SwiftSetting] = [
   .enableUpcomingFeature("ImmutableWeakCaptures"),
   .enableUpcomingFeature("MemberImportVisibility"),
   .enableUpcomingFeature("ExistentialAny"),
-  .enableUpcomingFeature("InternalImportsByDefault")
+  .enableUpcomingFeature("InternalImportsByDefault"),
+  .strictMemorySafety()
 ]
 
 // METARFormatting (and DecodeMETAR/DecodeTAF, which depend on it) format `Measurement`

Sources/SwiftMETAR/Common/Altimeter.swift

@@ -28,8 +28,8 @@ public enum Altimeter: CodedRepresentable, Comparable, Sendable {
    */
   public var codedString: String {
     switch self {
-      case .inHg(let value): "A\(String(format: "%04d", value))"
-      case .hPa(let value): "Q\(String(format: "%04d", value))"
+      case .inHg(let value): "A\(unsafe String(format: "%04d", value))"
+      case .hPa(let value): "Q\(unsafe String(format: "%04d", value))"
     }
   }
 
@@ -40,7 +40,7 @@ public enum Altimeter: CodedRepresentable, Comparable, Sendable {
    - Throws: ``Error/invalidAltimeter(_:)`` if `coded` is not a valid altimeter
              setting.
    */
-  public init(coded: String) throws {
+  public init(coded: String) throws(Error) {
     var parts = coded.split(whereSeparator: \.isWhitespace)
     guard let altimeter = try AltimeterParser().parseMETAR(&parts), parts.isEmpty else {
       throw Error.invalidAltimeter(coded)

Sources/SwiftMETAR/Common/CodedRepresentable.swift

@@ -22,7 +22,7 @@ public protocol CodedRepresentable: Codable {
    - Parameter coded: The coded string, e.g. `"03015KT"`.
    - Throws: An ``Error`` if `coded` is not a valid representation.
    */
-  init(coded: String) throws
+  init(coded: String) throws(Error)
 }
 
 extension CodedRepresentable {

Sources/SwiftMETAR/Common/Condition.swift

@@ -108,7 +108,7 @@ public enum Condition: CodedRepresentable, Equatable, Sendable {
    - Throws: ``Error/invalidConditions(_:)`` if `coded` is not a valid
              representation of a single sky condition.
    */
-  public init(coded: String) throws {
+  public init(coded: String) throws(Error) {
     if coded == "CAVOK" {
       self = .cavok
       return
@@ -123,7 +123,7 @@ public enum Condition: CodedRepresentable, Equatable, Sendable {
   }
 
   private static func heightGroup(_ feet: UInt) -> String {
-    String(format: "%03d", feet / 100)
+    unsafe String(format: "%03d", feet / 100)
   }
 
   private static func suffix(_ type: CeilingType?) -> String {

Sources/SwiftMETAR/Common/Parsers/CommonParsers.swift

@@ -1,4 +1,4 @@
-func parseLocationID(_ parts: inout [String.SubSequence]) throws -> String {
+func parseLocationID(_ parts: inout [String.SubSequence]) throws(Error) -> String {
   guard !parts.isEmpty else { throw Error.badFormat }
   return String(parts.removeFirst())
 }

Sources/SwiftMETAR/Common/Parsers/ConditionsParser.swift

@@ -5,12 +5,11 @@ final class ConditionsParser: WarmableParser, @unchecked Sendable {
   private static let coverageRef = Reference<Coverage>()
   private static let heightRef = Reference<UInt>()
   private static let ceilingTypeRef = Reference<Condition.CeilingType?>()
-  // swiftlint:disable force_try
   private static let rx = LockedRegex(
     Regex {
       Anchor.startOfSubject
       Capture(as: coverageRef) {
-        try! Coverage.rx
+        Coverage.rx
       } transform: {
         .init(rawValue: String($0))!
       }
@@ -20,16 +19,15 @@ final class ConditionsParser: WarmableParser, @unchecked Sendable {
         .init($0)! * 100
       }
       Capture(as: ceilingTypeRef) {
-        Optionally(try! Condition.CeilingType.rx)
+        Optionally(Condition.CeilingType.rx)
       } transform: {
         .init(rawValue: String($0))
       }
       Anchor.endOfSubject
     }
   )
-  // swiftlint:enable force_try
 
-  func parse(_ parts: inout [String.SubSequence]) throws -> [Condition] {
+  func parse(_ parts: inout [String.SubSequence]) throws(Error) -> [Condition] {
     if parts.isEmpty { return [] }
 
     var conditions = [Condition]()

Sources/SwiftMETAR/Common/Parsers/DateParser.swift

@@ -36,7 +36,7 @@ final class DayHourMinuteParser: WarmableParser, @unchecked Sendable {
     _ = try? anchoredRx.wholeMatch(in: "")
   }
 
-  func parse(_ parts: inout [String.SubSequence], referenceDate: Date? = nil) throws
+  func parse(_ parts: inout [String.SubSequence], referenceDate: Date? = nil) throws(Error)
     -> DateComponents
   {
     guard !parts.isEmpty else { throw Error.badFormat }
@@ -48,12 +48,13 @@ final class DayHourMinuteParser: WarmableParser, @unchecked Sendable {
     return try parse(match: match, referenceDate: referenceDate, originalString: dateStr)
   }
 
-  func matchesNext(_ parts: [String.SubSequence]) throws -> Bool {
+  func matchesNext(_ parts: [String.SubSequence]) throws(Error) -> Bool {
     guard let str = parts.first else { return false }
     return try anchoredRx.matches(String(str))
   }
 
-  func parse<T>(match: Regex<T>.Match, referenceDate: Date? = nil, originalString: String) throws
+  func parse<T>(match: Regex<T>.Match, referenceDate: Date? = nil, originalString: String)
+    throws(Error)
     -> DateComponents
   {
     var (day, hour, minute) = match[dateRef]
@@ -109,7 +110,7 @@ class DayHourParser {
     referenceDate: Date? = nil,
     afterDate afterDateComponents: DateComponents? = nil,
     originalString string: String
-  ) throws -> DateComponents {
+  ) throws(Error) -> DateComponents {
     var (day, hour) = match[dateRef]
     var addDay = false
     if hour == 24 {
@@ -198,7 +199,7 @@ class HourMinutePeriodParser {
     match: Regex<T>.Match,
     referenceDate: Date? = nil,
     originalString: String
-  ) throws -> DateComponentsInterval {
+  ) throws(Error) -> DateComponentsInterval {
     let startTime = try minuteOfDay(
       hour: match[startHourRef],
       minute: match[startMinuteRef],
@@ -227,7 +228,8 @@ class HourMinutePeriodParser {
 
   /// Converts an `HHMM` time to minutes past midnight, treating `2400` as the end
   /// of the day the way ``DayHourMinuteParser`` does.
-  private func minuteOfDay(hour: UInt8, minute: UInt8, originalString: String) throws -> Int {
+  private func minuteOfDay(hour: UInt8, minute: UInt8, originalString: String) throws(Error) -> Int
+  {
     guard hour <= 24, minute <= 59, hour < 24 || minute == 0 else {
       throw Error.invalidDate(originalString)
     }
@@ -276,7 +278,7 @@ class HourMinuteParser {
   }
 
   func parse<T>(match: Regex<T>.Match, referenceDate: Date? = nil, originalString string: String)
-    throws -> DateComponents
+    throws(Error) -> DateComponents
   {
     let (hour, minute) = match[dateRef]
 

Sources/SwiftMETAR/Common/Parsers/VisibilityParser.swift

@@ -41,7 +41,7 @@ final class VisibilityParser: WarmableParser, @unchecked Sendable {
     _ = try? fractionRx.wholeMatch(in: "")
   }
 
-  func parse(_ parts: inout [String.SubSequence]) throws -> Visibility? {
+  func parse(_ parts: inout [String.SubSequence]) throws(Error) -> Visibility? {
     guard !parts.isEmpty else { return nil }
 
     if parts.count >= 2 {
@@ -59,7 +59,7 @@ final class VisibilityParser: WarmableParser, @unchecked Sendable {
     return nil
   }
 
-  private func parse(_ vizStr: String) throws -> Visibility? {
+  private func parse(_ vizStr: String) throws(Error) -> Visibility? {
     if vizStr == "CAVOK" {
       return .greaterThan(.meters(9999))
     }
@@ -94,15 +94,13 @@ final class VisibilityParser: WarmableParser, @unchecked Sendable {
   class OpenRangeParser {
     private static let boundRef = Reference<OpenRange>()
 
-    // swiftlint:disable force_try
     static let rx = Regex {
       Capture(as: boundRef) {
-        try! OpenRange.rx
+        OpenRange.rx
       } transform: {
         .init(rawValue: String($0))!
       }
     }
-    // swiftlint:enable force_try
 
     func parse<T>(_ match: Regex<T>.Match) -> OpenRange {
       match[Self.boundRef]
@@ -124,7 +122,6 @@ final class VisibilityParser: WarmableParser, @unchecked Sendable {
     private static let valueRef = Reference<UInt16>()
     private static let unitRef = Reference<VisibilityDistanceUnit>()
 
-    // swiftlint:disable force_try
     static let rx = Regex {
       OpenRangeParser.rx
       Capture(as: valueRef) {
@@ -133,12 +130,11 @@ final class VisibilityParser: WarmableParser, @unchecked Sendable {
         .init($0)!
       }
       Capture(as: unitRef) {
-        try! Optionally(VisibilityDistanceUnit.rx)
+        Optionally(VisibilityDistanceUnit.rx)
       } transform: {
         .from(raw: String($0))!
       }
     }
-    // swiftlint:enable force_try
 
     private let openRangeParser = OpenRangeParser()
 

Sources/SwiftMETAR/Common/Parsers/WeatherParser.swift

@@ -6,22 +6,21 @@ final class WeatherParser: WarmableParser, @unchecked Sendable {
   private static let descriptorRef = Reference<Weather.Descriptor?>()
   private static let phenomenaRef = Reference<Substring>()
 
-  // swiftlint:disable force_try
   private static let weatherRx = LockedRegex(
     Regex {
       Anchor.startOfSubject
       Capture(as: intensityRef) {
-        try! Weather.Intensity.rx
+        Weather.Intensity.rx
       } transform: {
         .init(rawValue: String($0))!
       }
       Capture(as: descriptorRef) {
-        Optionally { try! Weather.Descriptor.rx }
+        Optionally { Weather.Descriptor.rx }
       } transform: {
         .init(rawValue: String($0))
       }
       Capture(as: phenomenaRef) {
-        OneOrMore { try! Weather.Phenomenon.rx }
+        OneOrMore { Weather.Phenomenon.rx }
       }
       Anchor.endOfSubject
     }
@@ -33,9 +32,8 @@ final class WeatherParser: WarmableParser, @unchecked Sendable {
       Anchor.endOfSubject
     }
   )
-  // swiftlint:enable force_try
 
-  func parse(_ parts: inout [String.SubSequence]) throws -> [Weather]? {
+  func parse(_ parts: inout [String.SubSequence]) throws(Error) -> [Weather]? {
     var weather = [Weather]()
 
     while true {
@@ -62,17 +60,16 @@ final class WeatherParser: WarmableParser, @unchecked Sendable {
         let intensity = match[Self.intensityRef]
         let descriptor = match[Self.descriptorRef]
 
-        let phenomenaStr = match[Self.phenomenaRef]
-        let phenomenaStrs = String(phenomenaStr).partition(by: 2)
-        let phenomena = try phenomenaStrs.map { code -> Weather.Phenomenon in
+        var phenomena = Set<Weather.Phenomenon>()
+        for code in String(match[Self.phenomenaRef]).partition(by: 2) {
           guard let phenomenon = Weather.Phenomenon(rawValue: code) else {
             throw Error.invalidWeather(weatherStr)
           }
-          return phenomenon
+          phenomena.insert(phenomenon)
         }
 
         weather.append(
-          Weather(intensity: intensity, descriptor: descriptor, phenomena: Set(phenomena))
+          Weather(intensity: intensity, descriptor: descriptor, phenomena: phenomena)
         )
       } else {
         return weather

Sources/SwiftMETAR/Common/Parsers/WindParser.swift

@@ -70,7 +70,7 @@ enum WindParser {
     }
   )
 
-  static func parse(_ parts: inout [String.SubSequence]) throws -> Wind? {
+  static func parse(_ parts: inout [String.SubSequence]) throws(Error) -> Wind? {
     guard !parts.isEmpty else { return nil }
     let dirAndSpeed = String(parts[0])
 
@@ -122,7 +122,7 @@ enum WindParser {
     }
   }
 
-  static func parse<T>(match: Regex<T>.Match, originalString: String) throws -> Wind {
+  static func parse<T>(match: Regex<T>.Match, originalString: String) throws(Error) -> Wind {
     let speedValue = match[speedRef]
     let speed: Wind.Speed =
       switch match[unitRef] {
@@ -155,7 +155,7 @@ enum WindParser {
   private static func parseDirectionRange(
     _ parts: inout [String.SubSequence],
     rangeSeq: String.SubSequence
-  ) throws -> (UInt16, UInt16)? {
+  ) throws(Error) -> (UInt16, UInt16)? {
     let rangeStr = String(rangeSeq)
 
     guard let variableMatch = try variableRx.wholeMatch(in: rangeStr),

Sources/SwiftMETAR/Common/Parsers/WindshearParser.swift

@@ -18,7 +18,7 @@ final class WindshearParser: WarmableParser, @unchecked Sendable {
     }
   )
 
-  func parse(_ parts: inout [String.SubSequence]) throws -> Windshear? {
+  func parse(_ parts: inout [String.SubSequence]) throws(Error) -> Windshear? {
     guard !parts.isEmpty else { return nil }
     let windshearStr = String(parts[0])
     guard let result = try Self.rx.wholeMatch(in: windshearStr) else { return nil }

Sources/SwiftMETAR/Common/Visibility.swift

@@ -65,7 +65,7 @@ public enum Visibility: CodedRepresentable, Equatable, Sendable {
    - Throws: ``Error/invalidVisibility(_:)`` if `coded` is not a valid
              visibility group.
    */
-  public init(coded: String) throws {
+  public init(coded: String) throws(Error) {
     var parts = coded.split(whereSeparator: \.isWhitespace)
     if let visibility = try VisibilityParser().parse(&parts), parts.isEmpty {
       self = visibility
@@ -172,7 +172,7 @@ public enum Visibility: CodedRepresentable, Equatable, Sendable {
      - Throws: ``Error/invalidVisibility(_:)`` if `coded` is not a valid,
                unqualified distance.
      */
-    public init(coded: String) throws {
+    public init(coded: String) throws(Error) {
       guard case let .equal(value) = try Visibility(coded: coded) else {
         throw Error.invalidVisibility(coded)
       }

Sources/SwiftMETAR/Common/Weather.swift

@@ -205,7 +205,7 @@ extension Weather: CodedRepresentable {
    - Throws: ``Error/invalidWeather(_:)`` if `coded` is not a single valid
              weather group.
    */
-  public init(coded: String) throws {
+  public init(coded: String) throws(Error) {
     var parts = coded.split(whereSeparator: \.isWhitespace)
     guard let weather = try WeatherParser().parse(&parts),
       weather.count == 1, parts.isEmpty