Merge pull request swiftlang#39 from nkcsgexi/isunknown

Add an API for unknown checking.

Author: nkcsgexi

Sources/SwiftSyntax/Syntax.swift

@@ -105,6 +105,11 @@ extension Syntax {
     return raw.kind.isPattern
   }
 
+  /// Whether or not this node represents an unknown node.
+  public var isUnknown: Bool {
+    return raw.kind.isUnknown
+  }
+
   /// The parent of this syntax node, or `nil` if this node is the root.
   public var parent: Syntax? {
     guard let parentData = data.parent else { return nil }

Sources/SwiftSyntax/SyntaxKind.swift.gyb

@@ -45,6 +45,18 @@ public enum SyntaxKind: String, Codable {
 %   end
 % end
 
+  public var isUnknown: Bool {
+    switch self {
+% for name, nodes in grouped_nodes.items():
+%   if name not in ["Syntax", "SyntaxCollection"]:
+    case .unknown${name}: return true
+%   end
+% end
+    case .unknown: return true
+    default: return false
+    }
+  }
+
   public init(from decoder: Decoder) throws {
     let container = try decoder.singleValueContainer()
     let kind = try container.decode(String.self)

Tests/SwiftSyntaxTest/SyntaxFactory.swift

@@ -22,6 +22,7 @@ public class SyntaxFactoryAPITestCase: XCTestCase {
     ("testGenerated", testGenerated),
     ("testTokenSyntax", testTokenSyntax),
     ("testFunctionCallSyntaxBuilder", testFunctionCallSyntaxBuilder),
+    ("testUnknownSyntax", testUnknownSyntax),
   ]
 
   public func testGenerated() {
@@ -115,4 +116,11 @@ public class SyntaxFactoryAPITestCase: XCTestCase {
     XCTAssertEqual("\(callWithTerminator)",
                    "print(\"Hello, world!\", terminator: \" \")")
   }
+
+  public func testUnknownSyntax() {
+    let expr = SyntaxFactory.makeStringLiteralExpr("Hello, world!")
+    XCTAssertFalse(expr.isUnknown)
+    XCTAssertTrue(SyntaxFactory.makeUnknownSyntax(
+      tokens: [SyntaxFactory.makeLeftBraceToken()]).isUnknown)
+  }
 }