Cross-platform example

Package.swift

@@ -15,7 +15,7 @@ let package = Package(
 		.library(name: "Neon", targets: ["Neon"]),
 	],
 	dependencies: [
-		.package(url: "https://github.com/ChimeHQ/SwiftTreeSitter", revision: "1ee3af86c3973c900a30e15507d117c58ed5acb2"),
+		.package(url: "https://github.com/ChimeHQ/SwiftTreeSitter", revision: "b01904a3737649c1d8520106bbb285724fe5b0bb"),
 		.package(url: "https://github.com/ChimeHQ/Rearrange", from: "1.8.1"),
 	],
 	targets: [

Projects/NeonExample.xcodeproj/project.pbxproj

@@ -330,8 +330,8 @@
 			isa = XCRemoteSwiftPackageReference;
 			repositoryURL = "https://github.com/mattmassicotte/nsui.git";
 			requirement = {
-				branch = main;
-				kind = branch;
+				kind = revision;
+				revision = d000e76f5587a1b7843717872b2f4a2318b0efbf;
 			};
 		};
 /* End XCRemoteSwiftPackageReference section */

Projects/NeonExample.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -5,8 +5,7 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/mattmassicotte/nsui.git",
       "state" : {
-        "branch" : "main",
-        "revision" : "783dce536c266956b3471ae77fb3b8a755184858"
+        "revision" : "d000e76f5587a1b7843717872b2f4a2318b0efbf"
       }
     },
     {
@@ -23,7 +22,7 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/ChimeHQ/SwiftTreeSitter",
       "state" : {
-        "revision" : "1ee3af86c3973c900a30e15507d117c58ed5acb2"
+        "revision" : "b01904a3737649c1d8520106bbb285724fe5b0bb"
       }
     },
     {

Projects/NeonExample/TextViewController.swift

@@ -22,18 +22,14 @@ final class TextViewController: NSUIViewController {
 			self.textView = NSUITextView()
 		}
 
-		// enable non-continguous layout for TextKit 1
-		if #available(macOS 12.0, iOS 16.0, *), textView.textLayoutManager == nil {
-#if canImport(AppKit) && !targetEnvironment(macCatalyst)
-			textView.layoutManager?.allowsNonContiguousLayout = true
-#else
-			textView.layoutManager.allowsNonContiguousLayout = true
-#endif
-		}
-
 		self.highlighter = try! Self.makeHighlighter(for: textView)
 
 		super.init(nibName: nil, bundle: nil)
+
+		// enable non-continguous layout for TextKit 1
+		if #available(macOS 12.0, iOS 16.0, *), textView.textLayoutManager == nil {
+			textView.nsuiLayoutManager?.allowsNonContiguousLayout = true
+		}
 	}
 
 	@available(*, unavailable)
@@ -44,13 +40,9 @@ final class TextViewController: NSUIViewController {
 	private static func makeHighlighter(for textView: NSUITextView) throws -> TextViewHighlighter {
 		let regularFont = NSUIFont.monospacedSystemFont(ofSize: 16, weight: .regular)
 		let boldFont = NSUIFont.monospacedSystemFont(ofSize: 16, weight: .bold)
-		let italicDescriptor = regularFont.fontDescriptor.withSymbolicTraits(.traitItalic)
+		let italicDescriptor = regularFont.fontDescriptor.nsuiWithSymbolicTraits(.traitItalic) ?? regularFont.fontDescriptor
 
-#if canImport(AppKit) && !targetEnvironment(macCatalyst)
-		let italicFont = NSUIFont(descriptor: italicDescriptor, size: 16) ?? regularFont
-#elseif canImport(UIKit)
-		let italicFont = NSUIFont(descriptor: italicDescriptor ?? regularFont.fontDescriptor, size: 16)
-#endif
+		let italicFont = NSUIFont(nsuiDescriptor: italicDescriptor, size: 16) ?? regularFont
 
 		// Set the default styles. This is applied by stock `NSTextStorage`s during
 		// so-called "attribute fixing" when you type, and we emulate that as
@@ -124,13 +116,13 @@ final class TextViewController: NSUIViewController {
 		textView.isRichText = false  // Discards any attributes when pasting.
 
 		self.view = scrollView
+#else
+		self.view = textView
+#endif
 
 		// this has to be done after the textview has been embedded in the scrollView if
 		// it wasn't that way on creation
 		highlighter.observeEnclosingScrollView()
-#else
-		self.view = textView
-#endif
 
 		regularTest()
 	}

Sources/Neon/PlatformTextSystem.swift

@@ -5,12 +5,10 @@ import RangeState
 #if os(macOS) && !targetEnvironment(macCatalyst)
 import AppKit
 
-public typealias TextStorageEditActions = NSTextStorageEditActions
 public typealias TextView = NSTextView
 #elseif os(iOS) || os(visionOS)
 import UIKit
 
-public typealias TextStorageEditActions = NSTextStorage.EditActions
 public typealias TextView = UITextView
 #endif
 

Sources/Neon/TextStorageDelegateBuffer.swift

@@ -0,0 +1,53 @@
+import Foundation
+
+#if os(macOS) && !targetEnvironment(macCatalyst)
+import AppKit
+
+typealias TextStorageEditActions = NSTextStorageEditActions
+#elseif os(iOS) || os(visionOS)
+import UIKit
+
+typealias TextStorageEditActions = NSTextStorage.EditActions
+#endif
+
+import RangeState
+
+#if os(macOS) || os(iOS) || os(visionOS)
+final class TextStorageDelegate: NSObject {
+	typealias ChangeHandler = (NSRange, Int) -> Void
+
+	public var storage: NSTextStorage? {
+		didSet {
+			oldValue?.delegate = nil
+			storage?.delegate = self
+		}
+	}
+	public var willChangeContent: ChangeHandler = { _, _ in }
+	public var didChangeContent: ChangeHandler = { _, _ in }
+}
+
+extension TextStorageDelegate: NSTextStorageDelegate {
+	public func textStorage(
+		_ textStorage: NSTextStorage,
+		willProcessEditing editedMask: TextStorageEditActions,
+		range editedRange: NSRange,
+		changeInLength delta: Int
+	) {
+		guard editedMask.contains(.editedCharacters) else { return }
+
+		willChangeContent(editedRange, delta)
+	}
+
+	public func textStorage(
+		_ textStorage: NSTextStorage,
+		didProcessEditing editedMask: TextStorageEditActions,
+		range editedRange: NSRange,
+		changeInLength delta: Int
+	) {
+		// it's important to filter these, as attribute changes can be caused by styling. This will result in an infinite loop.
+		guard editedMask.contains(.editedCharacters) else { return }
+
+		didChangeContent(editedRange, delta)
+	}
+}
+#endif

Sources/Neon/TextViewHighlighter.swift

@@ -38,7 +38,7 @@ extension TextView {
 /// for a TextView. The created instance will become the delegate of the
 /// view's `NSTextStorage`.
 @MainActor
-public final class TextViewHighlighter: NSObject {
+public final class TextViewHighlighter {
 	private typealias Styler = TextSystemStyler<TextViewSystemInterface>
 
 	public struct Configuration {
@@ -67,9 +67,11 @@ public final class TextViewHighlighter: NSObject {
 	private let interface: TextViewSystemInterface
 	private let client: TreeSitterClient
 	private let buffer = RangeInvalidationBuffer()
+	private let storageDelegate = TextStorageDelegate()
 
 #if os(iOS) || os(visionOS)
 	private var frameObservation: NSKeyValueObservation?
+	private var lastVisibleRange = NSRange.zero
 #endif
 
 	public init(
@@ -100,20 +102,51 @@ public final class TextViewHighlighter: NSObject {
 			tokenProvider: tokenProvider
 		)
 
-		super.init()
-
 		buffer.invalidationHandler = { [styler] in
 			styler.invalidate($0)
+
 			styler.validate()
 		}
 
-		try textView.getTextStorage().delegate = self
+		storageDelegate.willChangeContent = { [buffer, client] range, _ in
+			// a change happening, start buffering invalidations
+			buffer.beginBuffering()
+
+			client.willChangeContent(in: range)
+		}
+
+		storageDelegate.didChangeContent = { [buffer, client, styler] range, delta in
+			let adjustedRange = NSRange(location: range.location, length: range.length - delta)
+
+			client.didChangeContent(in: adjustedRange, delta: delta)
+			styler.didChangeContent(in: adjustedRange, delta: delta)
+
+			// At this point in mutation processing, it is unsafe to apply style changes. Ideally, we'd have a hook so we can know when it is ok. But, no such system exists for stock TextKit 1/2. So, instead we just let the runloop turn. This is *probably* safe, if the text does not change again, but can also result in flicker.
+			DispatchQueue.main.async {
+				buffer.endBuffering()
+			}
+
+		}
+
+		try textView.getTextStorage().delegate = storageDelegate
 
 		observeEnclosingScrollView()
 
 		invalidate(.all)
 	}
 
+	/// Perform manual invalidation on the underlying highlighter
+	public func invalidate(_ target: RangeTarget) {
+		buffer.invalidate(target)
+	}
+
+	/// Inform the client that calls to languageConfiguration may change.
+	public func languageConfigurationChanged(for name: String) {
+		client.languageConfigurationChanged(for: name)
+	}
+}
+
+extension TextViewHighlighter {
 	public func observeEnclosingScrollView() {
 #if os(macOS) && !targetEnvironment(macCatalyst)
 		guard let scrollView = textView.enclosingScrollView else {
@@ -135,9 +168,17 @@ public final class TextViewHighlighter: NSObject {
 			object: scrollView.contentView
 		)
 #elseif os(iOS) || os(visionOS)
-		self.frameObservation = textView.observe(\.contentOffset) { [styler] view, _ in
+		self.frameObservation = textView.observe(\.contentOffset) { [weak self] view, _ in
 			MainActor.backport.assumeIsolated {
-				styler.visibleContentDidChange()
+				guard let self = self else { return }
+
+				self.lastVisibleRange = self.textView.visibleTextRange
+
+				DispatchQueue.main.async {
+					guard self.textView.visibleTextRange == self.lastVisibleRange else { return }
+
+					self.styler.visibleContentDidChange()
+				}
 			}
 		}
 #endif
@@ -146,48 +187,6 @@ public final class TextViewHighlighter: NSObject {
 	@objc private func visibleContentChanged(_ notification: NSNotification) {
 		styler.visibleContentDidChange()
 	}
-
-	/// Perform manual invalidation on the underlying highlighter
-	public func invalidate(_ target: RangeTarget) {
-		buffer.invalidate(target)
-	}
-
-	public func languageConfigurationChanged(for name: String) {
-		client.languageConfigurationChanged(for: name)
-	}
-}
-
-extension TextViewHighlighter: NSTextStorageDelegate {
-	public nonisolated func textStorage(_ textStorage: NSTextStorage, willProcessEditing editedMask: TextStorageEditActions, range editedRange: NSRange, changeInLength delta: Int) {
-		MainActor.backport.assumeIsolated {
-			guard editedMask.contains(.editedCharacters) else { return }
-
-			// a change happening, start buffering invalidations
-			buffer.beginBuffering()
-
-			client.willChangeContent(in: editedRange)
-		}
-	}
-
-	public nonisolated func textStorage(_ textStorage: NSTextStorage, didProcessEditing editedMask: TextStorageEditActions, range editedRange: NSRange, changeInLength delta: Int) {
-		MainActor.backport.assumeIsolated {
-			// Avoid potential infinite loop in synchronous highlighting. If attributes
-			// are stored in `textStorage`, that applies `.editedAttributes` only.
-			// We don't need to re-apply highlighting in that case.
-			// (With asynchronous highlighting, it's not blocking, but also never stops.)
-			guard editedMask.contains(.editedCharacters) else { return }
-
-			let adjustedRange = NSRange(location: editedRange.location, length: editedRange.length - delta)
-
-			client.didChangeContent(in: adjustedRange, delta: delta)
-			styler.didChangeContent(in: adjustedRange, delta: delta)
-
-			// At this point in mutation processing, it is unsafe to apply style changes. Ideally, we'd have a hook so we can know when it is ok. But, no such system exists for stock TextKit 1/2. So, instead we just let the runloop turn. This is *probably* safe, if the text does not change again, but can also result in flicker.
-			DispatchQueue.main.async {
-				self.buffer.endBuffering()
-			}
-		}
-	}
 }
 
 #endif

Sources/RangeState/RangeTarget.swift

@@ -81,3 +81,17 @@ extension RangeTarget {
 		}
 	}
 }
+
+extension RangeTarget: CustomDebugStringConvertible {
+	public var debugDescription: String {
+		switch self {
+		case .all:
+			"all"
+		case let .range(range):
+			range.debugDescription
+		case let .set(set):
+			set.nsRangeView.debugDescription
+		}
+	}
+}
+