static highlighting

README.md

@@ -174,6 +174,27 @@ let highlights = try client.highlights(in: NSRange(0..<24), provider: provider,
 print("highlights:", highlights)
 ```
 
+TreeSitterClient can also perform static highlighting. This can be handy for applying style to a string.
+
+```swift
+let languageConfig = try LanguageConfiguration(
+    tree_sitter_swift(),
+    name: "Swift"
+)
+
+let attrProvider: TokenAttributeProvider = { token in
+    return [.foregroundColor: NSColor.red]
+}
+
+// produce an AttributedString
+let highlightedSource = try await TreeSitterClient.highlight(
+    string: source,
+    attributeProvider: attrProvider,
+    rootLanguageConfig: languageConfig,
+    languageProvider: { _ in nil }
+)
+```
+
 ## Contributing and Collaboration
 
 I would love to hear from you! Issues or pull requests work great. A [Discord server][discord] is also available for live help, but I have a strong bias towards answering in the form of documentation.

Sources/Neon/PlatformTextSystem.swift

@@ -6,10 +6,12 @@ import RangeState
 import AppKit
 
 public typealias TextView = NSTextView
+typealias PlatformColor = NSColor
 #elseif os(iOS) || os(visionOS)
 import UIKit
 
 public typealias TextView = UITextView
+typealias PlatformColor = UIColor
 #endif
 
 #if os(macOS) || os(iOS) || os(visionOS)

Sources/Neon/TreeSitterClient+Neon.swift

@@ -66,3 +66,45 @@ extension TextViewSystemInterface {
 	}
 }
 #endif
+
+@available(macOS 12, *)
+extension TreeSitterClient {
+	/// Highlight an input string.
+	public static func highlight(
+		string: String,
+		attributeProvider: TokenAttributeProvider,
+		rootLanguageConfig: LanguageConfiguration,
+		languageProvider: @escaping LanguageLayer.LanguageProvider
+	) async throws -> AttributedString {
+		let content = LanguageLayer.Content(string: string)
+		let length = string.utf16.count
+
+		let client = try TreeSitterClient(
+			rootLanguageConfig: rootLanguageConfig,
+			configuration: Configuration(
+				languageProvider: languageProvider,
+				contentProvider: { _ in content },
+				lengthProvider: { length },
+				invalidationHandler: { _ in },
+				locationTransformer: { _ in nil }
+			)
+		)
+
+		client.didChangeContent(in: NSRange(0..<0), delta: length)
+
+		let ranges = try await client.highlights(in: NSRange(0..<length), provider: content.textProvider)
+
+		var attributedString = AttributedString(stringLiteral: string)
+
+		for range in ranges {
+			let token = Token(name: range.name, range: range.range)
+			let attrs = attributeProvider(token)
+			guard let strRange = Range<AttributedString.Index>(token.range, in: attributedString) else { continue }
+
+			attributedString[strRange].foregroundColor = attrs[.foregroundColor] as? PlatformColor
+		}
+
+		return attributedString
+	}
+}
+

Tests/NeonTests/TextViewSystemInterfaceTests.swift

@@ -4,8 +4,6 @@ import XCTest
 #if os(macOS)
 import AppKit
 
-typealias PlatformColor = NSColor
-
 extension NSTextView {
 	var text: String {
 		get { return string }
@@ -31,7 +29,6 @@ extension NSTextView {
 #elseif os(iOS)
 import UIKit
 
-typealias PlatformColor = UIColor
 #endif
 
 //final class TextViewSystemInterfaceTests: XCTestCase {