Query definitions

README.md

@@ -7,6 +7,11 @@
 
 Swift API for the [tree-sitter](https://tree-sitter.github.io/) incremental parsing system.
 
+- Close to full coverage of the C API
+- Swift/Foundation types where possible
+- Standard query result mapping for injections
+- Query predicate support via `ResolvingQueryCursor`
+
 SwiftTreeSitter is fairly low-level. If you are looking a higher-level system for syntax highlighting and other syntactic operations, you might want to have a look at [Neon](https://github.com/ChimeHQ/Neon).
 
 📖 [Documentation][documentation] is available in DocC format.

Sources/SwiftTreeSitter/QueryDefinitions.swift

@@ -0,0 +1,47 @@
+import Foundation
+
+/// A combined name and range
+///
+/// Useful for generalizing data from query matches.
+public struct NamedRange {
+	public let name: String
+	public let range: NSRange
+
+	public init(name: String, range: NSRange) {
+		self.name = name
+		self.range = range
+	}
+}
+
+public extension QueryMatch {
+	/// Intrepret the match using the "injections.scm" definition
+	///
+	/// - `injection.content` defines the range of the injection
+	/// - a node with `injection.language` specifies the value of the language in the text
+	/// - if that is not prsent, uses `injection.language` metadata
+	///
+	/// If `textProvider` is nil and a node contents is needed, the injection is dropped.
+	func injection(with textProvider: ResolvingQueryCursor.TextProvider?) -> NamedRange? {
+		guard let range = captures(named: "injection.content").first?.range else {
+			return nil
+		}
+
+		let languageCapture = captures(named: "injection.language").first
+
+		let nodeLanguage: String?
+
+		if let node = languageCapture?.node {
+			nodeLanguage = textProvider?(node.range, node.pointRange)
+		} else {
+			nodeLanguage = nil
+		}
+
+		let setLanguage = metadata["injection.language"]
+
+		guard let language = nodeLanguage ?? setLanguage else {
+			return nil
+		}
+
+		return NamedRange(name: language, range: range)
+	}
+}