Basic Gherkin and ReqsML Parsing & Testing

.gitignore

@@ -0,0 +1,25 @@
+
+# Xcode
+
+
+## Mac specific
+*.DS_Store
+
+
+## User settings
+xcuserdata/
+
+
+# Swift Package Manager
+
+Packages/
+Package.pins
+Package.resolved
+*.xcodeproj
+
+
+# Xcode automatically generates this directory with a .xcworkspacedata file and xcuserdata
+# hence it is not needed unless you have added a package configuration file to your project
+
+.swiftpm
+.build/

Package.swift

@@ -0,0 +1,33 @@
+// swift-tools-version: 5.7
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "RequirementsKit",
+    platforms: [.iOS(.v16), .macOS(.v13), .macCatalyst(.v16)],
+    products: [
+        // Products define the executables and libraries a package produces, and make them visible to other packages.
+        .library(
+            name: "RequirementsKit",
+            targets: ["RequirementsKit"]),
+    ],
+    dependencies: [
+        // Dependencies declare other packages that this package depends on.
+        .package(url: "https://github.com/apple/swift-collections", exact: "1.0.4"),
+    ],
+    targets: [
+        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
+        // Targets can depend on other targets in this package, and on products in packages this package depends on.
+        .target(
+            name: "RequirementsKit",
+            dependencies: [
+                .product(name: "OrderedCollections", package: "swift-collections"),
+            ]
+        ),
+        .testTarget(
+            name: "RequirementsKitTests",
+            dependencies: ["RequirementsKit"],
+            resources: [.copy("TestResources")]),
+    ]
+)

README.md

@@ -0,0 +1,3 @@
+# RequirementsKit
+
+A library for parsing and testing functional requirements in Swift

Sources/RequirementsKit/LabelExpression.swift

@@ -0,0 +1,144 @@
+//
+//  LabelExpression.swift
+//  RequirementsKit
+//
+//  Copyright (c) 2022 - 2023 Daniel Hall (https://danielhall.io)
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+public indirect enum LabelExpression {
+    case label(String)
+    case not(String)
+    case orLabel(LabelExpression, String)
+    case andLabel(LabelExpression, String)
+    case orNotLabel(LabelExpression, String)
+    case andNotLabel(LabelExpression, String)
+    case orExpression(LabelExpression, LabelExpression)
+    case andExpression(LabelExpression, LabelExpression)
+    case orNotExpression(LabelExpression, LabelExpression)
+    case andNotExpression(LabelExpression, LabelExpression)
+
+    public func or(_ string: String) -> LabelExpression {
+        return .orLabel(self, string)
+    }
+
+    public func and(_ string: String) -> LabelExpression {
+        return .andLabel(self, string)
+    }
+
+    public func orNot(_ string: String) -> LabelExpression {
+        return .orNotLabel(self, string)
+    }
+
+    public func andNot(_ string: String) -> LabelExpression {
+        return .andNotLabel(self, string)
+    }
+
+    public func or(_ expression: LabelExpression) -> LabelExpression {
+        return .orExpression(self, expression)
+    }
+
+    public func and(_ expression: LabelExpression) -> LabelExpression {
+        return .andExpression(self, expression)
+    }
+
+    public func orNot(_ expression: LabelExpression) -> LabelExpression {
+        return .orNotExpression(self, expression)
+    }
+
+    public func andNot(_ expression: LabelExpression) -> LabelExpression {
+        return .andNotExpression(self, expression)
+    }
+
+    private enum MatchResult {
+        case success
+        case notIncluded
+        case excluded
+        case notIncludedAndExcluded
+        case failure
+    }
+
+    private func matchResult(_ labels: [String]) -> MatchResult {
+        switch self {
+
+        case .label(let string):
+            return labels.contains(string) ? .success : .notIncluded
+
+        case .not(let string):
+            return !labels.contains(string) ? .success : .excluded
+
+        case .andLabel(let expression, let string):
+            switch expression.matchResult(labels) {
+            case .success: return labels.contains(string) ? .success : .notIncluded
+            case .excluded: return labels.contains(string) ? .excluded : .notIncludedAndExcluded
+            case .notIncluded: return .notIncluded
+            case .notIncludedAndExcluded: return .notIncludedAndExcluded
+            case .failure: return .failure
+            }
+
+        case .orLabel(let expression, let string):
+            switch expression.matchResult(labels) {
+            case .success: return .success
+            case .excluded: return labels.contains(string) ? .excluded : .notIncludedAndExcluded
+            case .notIncluded: return labels.contains(string) ? .success : .notIncluded
+            case .notIncludedAndExcluded: return labels.contains(string) ? .excluded : .notIncludedAndExcluded
+            case .failure: return .failure
+            }
+
+        case .orNotLabel(let expression, let string):
+            switch expression.matchResult(labels) {
+            case .success: return .success
+            case .excluded: return !labels.contains(string) ? .success : .excluded
+            case .notIncluded: return .notIncluded
+            case .notIncludedAndExcluded: return !labels.contains(string) ? .notIncluded : .notIncludedAndExcluded
+            case .failure: return .failure
+            }
+
+        case .andNotLabel(let expression, let string):
+            switch expression.matchResult(labels) {
+            case .success: return !labels.contains(string) ? .success : .excluded
+            case .excluded: return .excluded
+            case .notIncluded: return !labels.contains(string) ? .notIncluded : .notIncludedAndExcluded
+            case .notIncludedAndExcluded: return .notIncludedAndExcluded
+            case .failure: return .failure
+            }
+
+        case .orExpression(let first, let second):
+            return first.matchResult(labels) == .success || second.matchResult(labels) == .success ? .success : .failure
+
+        case .andExpression(let first, let second):
+            return first.matchResult(labels) == .success && second.matchResult(labels) == .success ? .success : .failure
+
+        case .orNotExpression(let first, let second):
+            return first.matchResult(labels) == .success || second.matchResult(labels) != .success ? .success : .failure
+
+        case .andNotExpression(let first, let second):
+            return first.matchResult(labels) == .success && second.matchResult(labels) == .success ? .success : .failure
+        }
+    }
+
+    public func matches(_ labels: [String]?) -> Bool {
+        return matchResult(labels ?? []) == .success
+    }
+
+    public func matches(_ label: String) -> Bool {
+        return matches([label])
+    }
+}