Make SyntaxKind internal

`SyntaxKind` was made public in order to provide a visitation check for clients. Since the visitation check has been removed there's no need for `SyntaxKind` to be public.
Additional changes:

* Make `SyntaxKind` have CSyntaxKind as raw type. Avoids having to convert between them.
* Remove protocol `IncrementalParseLookup`. It can't be public since `SyntaxKind` is internal, and it's not much use to external clients anyway.
* Rename `IncrementalEditTransition` -> `IncrementalParseTransition`.

Author: akyrtzi

Sources/SwiftSyntax/IncrementalEditTransition.swift renamed to Sources/SwiftSyntax/IncrementalParseTransition.swift

@@ -1,4 +1,4 @@
-//===------ IncrementalEditTransition.swift - Edit Transition State -------===//
+//===------ IncrementalParseTransition.swift - Parse Transition State -----===//
 //
 // This source file is part of the Swift.org open source project
 //
@@ -10,7 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-/// Accepts the re-used `Syntax` nodes that `IncrementalEditTransition`
+/// Accepts the re-used `Syntax` nodes that `IncrementalParseTransition`
 /// determined they should be re-used for a parse invocation.
 ///
 /// The client can use this information to potentially avoid unnecessary work
@@ -42,10 +42,10 @@ public final class IncrementalParseReusedNodeCollector:
 }
 
 /// Keeps track of a previously parsed syntax tree and the source edits that
-/// occurred since it was created and provides the `IncrementalParseLookup`
-/// implementation to allow the parser to skip regions of the new source that
-/// can be associated with valid `Syntax` nodes from the previous tree.
-public final class IncrementalEditTransition: IncrementalParseLookup {
+/// occurred since it was created and provides a mechanism for the parser to
+/// skip regions of an incrementally updated source that was already parsed
+/// during a previous parse invocation.
+public final class IncrementalParseTransition {
   // The implementation is based on `SyntaxParsingCache` from the swift
   // repository.
 
@@ -65,7 +65,7 @@ public final class IncrementalEditTransition: IncrementalParseLookup {
   public init(previousTree: SourceFileSyntax,
               edits: [SourceEdit],
               reusedNodeDelegate: IncrementalParseReusedNodeDelegate? = nil) {
-    assert(IncrementalEditTransition.isEditArrayValid(edits))
+    assert(IncrementalParseTransition.isEditArrayValid(edits))
     self.previousTree = previousTree
     self.edits = edits
     self.reusedDelegate = reusedNodeDelegate
@@ -88,7 +88,19 @@ public final class IncrementalEditTransition: IncrementalParseLookup {
     return true
   }
 
-  public func lookUp(_ newOffset: Int, kind: SyntaxKind) -> Syntax? {
+  /// Does a lookup to see if the current source `offset` should be associated
+  /// with a known `Syntax` node and its region skipped during parsing.
+  ///
+  /// The implementation is responsible for checking whether an incremental edit
+  /// has invalidated the previous `Syntax` node.
+  ///
+  /// - Parameters:
+  ///   - offset: The byte offset of the source string that is currently parsed.
+  ///   - kind: The `SyntaxKind` that the parser expects at this position.
+  /// - Returns: A `Syntax` node from the previous parse invocation,
+  ///            representing the contents of this region, if it is still valid
+  ///            to re-use. `nil` otherwise.
+  func lookUp(_ newOffset: Int, kind: SyntaxKind) -> _SyntaxBase? {
     guard let prevOffset = translateToPreEditOffset(newOffset) else {
       return nil
     }
@@ -117,7 +129,7 @@ public final class IncrementalEditTransition: IncrementalParseLookup {
       }
       let childEnd = childOffset + child.byteSize
       if childOffset <= prevOffset && prevOffset < childEnd {
-        return lookUpFrom(child.base, nodeOffset: childOffset,
+        return lookUpFrom(child, nodeOffset: childOffset,
                           prevOffset: prevOffset, kind: kind)
       }
       // The next child starts where the previous child ended

Sources/SwiftSyntax/SyntaxKind.swift.gyb

@@ -21,14 +21,12 @@
 //
 //===----------------------------------------------------------------------===//
 
-import Foundation
-
 /// Enumerates the known kinds of Syntax represented in the Syntax tree.
-public enum SyntaxKind: String {
-  case token = "Token"
-  case unknown = "Unknown"
+internal enum SyntaxKind: CSyntaxKind {
+  case token = 0
+  case unknown = 1
 % for node in SYNTAX_NODES:
-  case ${node.swift_syntax_kind} = "${node.syntax_kind}"
+  case ${node.swift_syntax_kind} = ${SYNTAX_NODE_SERIALIZATION_CODES[node.syntax_kind]}
 % end
 
 % for name, nodes in grouped_nodes.items():
@@ -56,11 +54,11 @@ public enum SyntaxKind: String {
     default: return false
     }
   }
+}
 
-  public init(from decoder: Decoder) throws {
-    let container = try decoder.singleValueContainer()
-    let kind = try container.decode(String.self)
-    self = SyntaxKind(rawValue: kind) ?? .unknown
+extension SyntaxKind {
+  static func fromRawValue(_ rawValue: CSyntaxKind) -> SyntaxKind {
+    return SyntaxKind(rawValue: rawValue)!
   }
 }
 
@@ -83,25 +81,3 @@ internal func makeSyntax(_ data: SyntaxData) -> _SyntaxBase {
 % end
   }
 }
-
-
-extension SyntaxKind {
-  static func fromRawValue(_ rawValue: CSyntaxKind) -> SyntaxKind {
-    // Explicitly spell out all SyntaxKinds to keep the serialized value stable
-    // even if its members get reordered or members get removed
-    switch rawValue {
-    case 0:
-      return .token
-    case 1:
-      return .unknown
-% for name, nodes in grouped_nodes.items():
-%   for node in nodes:
-    case ${SYNTAX_NODE_SERIALIZATION_CODES[node.syntax_kind]}:
-      return .${node.swift_syntax_kind}
-%   end
-% end
-    default:
-      return .unknown
-    }
-  }
-}

Sources/SwiftSyntax/SyntaxParser.swift

@@ -49,26 +49,8 @@ public enum ParserError: Error, CustomStringConvertible {
   }
 }
 
-/// Provides a mechanism for the parser to skip regions of an incrementally
-/// updated source that were already parsed during a previous parse invocation.
-public protocol IncrementalParseLookup {
-  /// Does a lookup to see if the current source `offset` should be associated
-  /// with a known `Syntax` node and its region skipped during parsing.
-  ///
-  /// The implementation is responsible for checking whether an incremental edit
-  /// has invalidated the previous `Syntax` node.
-  ///
-  /// - Parameters:
-  ///   - offset: The byte offset of the source string that is currently parsed.
-  ///   - kind: The `SyntaxKind` that the parser expects at this position.
-  /// - Returns: A `Syntax` node from the previous parse invocation,
-  ///            representing the contents of this region, if it is still valid
-  ///            to re-use. `nil` otherwise.
-  func lookUp(_ offset: Int, kind: SyntaxKind) -> Syntax?
-}
-
 /// Namespace for functions to parse swift source and retrieve a syntax tree.
-public struct SyntaxParser {
+public enum SyntaxParser {
 
   /// True if the parser library is compatible with the SwiftSyntax client;
   /// false otherwise.
@@ -78,13 +60,13 @@ public struct SyntaxParser {
   ///
   /// - Parameters:
   ///   - source: The source string to parse.
-  ///   - parseLookup: Optional mechanism for incremental re-parsing.
+  ///   - parseTransition: Optional mechanism for incremental re-parsing.
   /// - Returns: A top-level Syntax node representing the contents of the tree,
   ///            if the parse was successful.
   /// - Throws: `ParserError`
   public static func parse(
     source: String,
-    parseLookup: IncrementalParseLookup? = nil
+    parseTransition: IncrementalParseTransition? = nil
   ) throws -> SourceFileSyntax {
     guard nodeHashVerifyResult else {
       throw ParserError.parserCompatibilityCheckFailed
@@ -95,7 +77,7 @@ public struct SyntaxParser {
     var utf8Source = source
     utf8Source.makeNativeUTF8IfNeeded()
 
-    let rawSyntax = parseRaw(utf8Source, parseLookup: parseLookup)
+    let rawSyntax = parseRaw(utf8Source, parseTransition)
 
     guard let file = makeSyntax(.forRoot(rawSyntax)) as? SourceFileSyntax else {
       throw ParserError.invalidSyntaxData
@@ -122,7 +104,7 @@ public struct SyntaxParser {
 
   private static func parseRaw(
     _ source: String,
-    parseLookup: IncrementalParseLookup?
+    _ parseTransition: IncrementalParseTransition?
   ) -> RawSyntax {
     assert(source.isNativeUTF8)
     let c_parser = swiftparse_parser_create()
@@ -139,12 +121,11 @@ public struct SyntaxParser {
     }
     swiftparse_parser_set_node_handler(c_parser, nodeHandler);
 
-    if let parseLookup = parseLookup {
+    if let parseTransition = parseTransition {
       let nodeLookup = {
             (offset: Int, kind: CSyntaxKind) -> CParseLookupResult in
         guard let foundNode =
-            parseLookup.lookUp(offset,
-                               kind: SyntaxKind.fromRawValue(kind)) else {
+            parseTransition.lookUp(offset, kind: .fromRawValue(kind)) else {
           return CParseLookupResult(length: 0, node: nil)
         }
         let lengthToSkip = foundNode.byteSize

Sources/lit-test-helper/main.swift

@@ -272,12 +272,12 @@ func performParseIncremental(args: CommandLineArguments) throws {
   let preEditTree = try SyntaxParser.parse(preEditURL)
   let edits = try parseIncrementalEditArguments(args: args)
   let regionCollector = IncrementalParseReusedNodeCollector()
-  let editTransition = IncrementalEditTransition(previousTree: preEditTree,
+  let editTransition = IncrementalParseTransition(previousTree: preEditTree,
     edits: edits, reusedNodeDelegate: regionCollector)
 
   let postEditText = try String(contentsOf: postEditURL)
   let postEditTree =
-    try SyntaxParser.parse(source: postEditText, parseLookup: editTransition)
+    try SyntaxParser.parse(source: postEditText, parseTransition: editTransition)
 
   let postTreeDump = postEditTree.description
 

Tests/SwiftSyntaxTest/IncrementalParsingTests.swift

@@ -14,8 +14,8 @@ public class IncrementalParsingTestCase: XCTestCase {
 
     var tree = try! SyntaxParser.parse(source: original)
     let sourceEdit = SourceEdit(range: ByteSourceRange(offset: step.1.0, length: step.1.1), replacementLength: step.1.2.utf8.count)
-    let lookup = IncrementalEditTransition(previousTree: tree, edits: [sourceEdit])
-    tree = try! SyntaxParser.parse(source: step.0, parseLookup: lookup)
+    let lookup = IncrementalParseTransition(previousTree: tree, edits: [sourceEdit])
+    tree = try! SyntaxParser.parse(source: step.0, parseTransition: lookup)
     XCTAssertEqual("\(tree)", step.0)
   }
 }