feat(strikethrough): Allow single ~ strikethrough

.github/workflows/unittests.yml

@@ -20,12 +20,11 @@ permissions:
 jobs:
   build-and-test:
     name: Build and Test
-    runs-on: macOS-latest
-    if: github.event.pull_request.draft == false
+    runs-on: macos-15
 
     env:
       WORKSPACE: CDMarkdownKit.xcworkspace
-      DESTINATION: platform=iOS Simulator,name=iPhone 14,OS=16.2
+      DESTINATION: platform=iOS Simulator,name=iPhone 16,OS=18.0
       SCHEME: "CDMarkdownKit iOS"
 
     steps:

CDMarkdownKit.xcodeproj/project.pbxproj

@@ -9,6 +9,7 @@
 /* Begin PBXBuildFile section */
 		1F02B85A2A90D60D0023148B /* TestSyntax.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1F02B8592A90D60D0023148B /* TestSyntax.swift */; };
 		1F02B85C2A90D6210023148B /* TestHelpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1F02B85B2A90D6210023148B /* TestHelpers.swift */; };
+		1F549C1B2D3EF78C00E9AA9E /* TestStrikethrough.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1F549C1A2D3EF78C00E9AA9E /* TestStrikethrough.swift */; };
 		1F66CB672A8EB04C00FC7BA7 /* TestItalic.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1F66CB662A8EB04C00FC7BA7 /* TestItalic.swift */; };
 		1F66CB682A8EB04C00FC7BA7 /* CDMarkdownKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = B2B365B71F3245800078B962 /* CDMarkdownKit.framework */; };
 		1F66CB7A2A8FBC1000FC7BA7 /* TestBold.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1F66CB792A8FBC1000FC7BA7 /* TestBold.swift */; };
@@ -178,6 +179,7 @@
 /* Begin PBXFileReference section */
 		1F02B8592A90D60D0023148B /* TestSyntax.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TestSyntax.swift; sourceTree = "<group>"; };
 		1F02B85B2A90D6210023148B /* TestHelpers.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TestHelpers.swift; sourceTree = "<group>"; };
+		1F549C1A2D3EF78C00E9AA9E /* TestStrikethrough.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TestStrikethrough.swift; sourceTree = "<group>"; };
 		1F66CB642A8EB04C00FC7BA7 /* CDMarkdownKitTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = CDMarkdownKitTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		1F66CB662A8EB04C00FC7BA7 /* TestItalic.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TestItalic.swift; sourceTree = "<group>"; };
 		1F66CB792A8FBC1000FC7BA7 /* TestBold.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TestBold.swift; sourceTree = "<group>"; };
@@ -288,6 +290,7 @@
 				1F8538482ADFE12E0011FE81 /* TestEscape.swift */,
 				1F9A797C2A98B4AF00E153E3 /* TestHeader.swift */,
 				1F02B8592A90D60D0023148B /* TestSyntax.swift */,
+				1F549C1A2D3EF78C00E9AA9E /* TestStrikethrough.swift */,
 			);
 			path = CDMarkdownKitTests;
 			sourceTree = "<group>";
@@ -715,6 +718,7 @@
 				1F66CB7A2A8FBC1000FC7BA7 /* TestBold.swift in Sources */,
 				1F02B85C2A90D6210023148B /* TestHelpers.swift in Sources */,
 				1F66CB7C2A8FBC8F00FC7BA7 /* TestCode.swift in Sources */,
+				1F549C1B2D3EF78C00E9AA9E /* TestStrikethrough.swift in Sources */,
 				1F02B85A2A90D60D0023148B /* TestSyntax.swift in Sources */,
 				1F66CB672A8EB04C00FC7BA7 /* TestItalic.swift in Sources */,
 			);

CDMarkdownKitTests/TestHelpers.swift

@@ -42,6 +42,12 @@ class TestHelpers {
         return isHelper(testString: testString, at: location, trait: .traitMonoSpace)
     }
 
+    static func isStrikethrough(testString: NSAttributedString, at location: Int) -> Bool {
+        let attributes = testString.attributes(at: location, effectiveRange: nil)
+
+        return attributes.contains { $0.key == .strikethroughStyle && NSUnderlineStyle(rawValue: $0.value as! Int) == .single }
+    }
+
     private static func anyHelper(testString: NSAttributedString, trait: UIFontDescriptor.SymbolicTraits) -> Bool {
         var found = false
 

CDMarkdownKitTests/TestStrikethrough.swift

@@ -0,0 +1,46 @@
+//
+// Copyright (c) 2025 Marcel Müller <marcel-mueller@gmx.de>
+//
+// Author Marcel Müller <marcel-mueller@gmx.de>
+//
+// GNU GPL version 3 or any later version
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+import XCTest
+import CDMarkdownKit
+
+final class TestStrikethrough: XCTestCase {
+
+    func testStrikethrough() throws {
+        let parser = CDMarkdownParser()
+
+        var parsed = parser.parse("~~Test~~")
+        XCTAssertEqual(parsed.string, "Test")
+        XCTAssertTrue(TestHelpers.isStrikethrough(testString: parsed, at: 0))
+
+        parsed = parser.parse("~Test~")
+        XCTAssertEqual(parsed.string, "Test")
+        XCTAssertTrue(TestHelpers.isStrikethrough(testString: parsed, at: 0))
+    }
+
+    func testNonStrikethrough() throws {
+        let parser = CDMarkdownParser()
+
+        let parsed = parser.parse("~~Test~")
+        XCTAssertEqual(parsed.string, "Test~")
+        XCTAssertFalse(TestHelpers.isStrikethrough(testString: parsed, at: 0))
+    }
+}

Source/CDMarkdownStrikethrough.swift

@@ -33,7 +33,7 @@
 
 open class CDMarkdownStrikethrough: CDMarkdownCommonElement {
 
-    fileprivate static let regex = ["()(~~)(.*?)(\\2)"]
+    fileprivate static let regex = ["()(~{1,2})(.*?)(\\2)"]
 
     open var font: CDFont?
     open var color: CDColor?