enumerate Trivia position leading/trailing

Author: rintaro

Sources/SwiftSyntax/RawSyntax.swift

@@ -170,7 +170,7 @@ extension RawSyntax {
   var tokenLeadingRawTriviaPieces: [RawTriviaPiece] {
     switch rawData.payload {
     case .parsedToken(let dat):
-      return self.arena.parseTrivia(source: dat.leadingTriviaText, isTrailing: false)
+      return self.arena.parseTrivia(source: dat.leadingTriviaText, position: .leading)
     case .materializedToken(let dat):
       return Array(dat.leadingTrivia)
     case .layout(_):
@@ -181,7 +181,7 @@ extension RawSyntax {
   var tokenTrailingRawTriviaPieces: [RawTriviaPiece] {
     switch rawData.payload {
     case .parsedToken(let dat):
-      return self.arena.parseTrivia(source: dat.trailingTriviaText, isTrailing: false)
+      return self.arena.parseTrivia(source: dat.trailingTriviaText, position: .trailing)
     case .materializedToken(let dat):
       return Array(dat.trailingTrivia)
     case .layout(_):

Sources/SwiftSyntax/SyntaxArena.swift

@@ -13,7 +13,7 @@
 public class SyntaxArena {
 
   @_spi(RawSyntax)
-  public typealias ParseTriviaFunction = (_ source: SyntaxText, _ isTrailing: Bool) -> [RawTriviaPiece]
+  public typealias ParseTriviaFunction = (_ source: SyntaxText, _ position: TriviaPosition) -> [RawTriviaPiece]
 
   /// Bump-pointer allocator for all "intern" methods.
   private var allocator: BumpPtrAllocator
@@ -158,8 +158,8 @@ public class SyntaxArena {
   }
 
   @_spi(RawSyntax)
-  public func parseTrivia(source: SyntaxText, isTrailing: Bool) -> [RawTriviaPiece] {
-    return parseTriviaFunction(source, isTrailing)
+  public func parseTrivia(source: SyntaxText, position: TriviaPosition) -> [RawTriviaPiece] {
+    return self.parseTriviaFunction(source, position)
   }
 }
 
@@ -201,6 +201,6 @@ extension SyntaxArena {
   public static let `default` = SyntaxArena()
 }
 
-private func _defaultParseTriviaFunction(_ source: SyntaxText, _ isTrailnig: Bool) -> [RawTriviaPiece] {
+private func _defaultParseTriviaFunction(_ source: SyntaxText, _ position: TriviaPosition) -> [RawTriviaPiece] {
   preconditionFailure("Trivia parsing not supported")
 }

Sources/SwiftSyntax/Trivia.swift.gyb

@@ -17,6 +17,11 @@
 //
 //===----------------------------------------------------------------------===//
 
+public enum TriviaPosition {
+  case leading
+  case trailing
+}
+
 /// A contiguous stretch of a single kind of trivia. The constituent part of
 /// a `Trivia` collection.
 ///

Sources/SwiftSyntax/gyb_generated/Trivia.swift

@@ -12,6 +12,11 @@
 //
 //===----------------------------------------------------------------------===//
 
+public enum TriviaPosition {
+  case leading
+  case trailing
+}
+
 /// A contiguous stretch of a single kind of trivia. The constituent part of
 /// a `Trivia` collection.
 ///

Tests/SwiftSyntaxTest/RawSyntaxTests.swift

@@ -82,7 +82,7 @@ final class RawSyntaxTests: XCTestCase {
 
   func testParsedToken() throws {
     // Dummy trivia parsing function.
-    func dummyParseToken(source: SyntaxText, isTrailing: Bool) -> [RawTriviaPiece] {
+    func dummyParseToken(source: SyntaxText, position: TriviaPosition) -> [RawTriviaPiece] {
       // Emit a single `unexpectedText` trivia of the whole trivia text.
       return [.unexpectedText(source)]
     }