Merge pull request #2813 from AppAppWorks/improve-identifier-backticking

[CodeGeneration] Improve identifier backticking

Author: ahoppen

CodeGeneration/Sources/SyntaxSupport/Child.swift

@@ -14,7 +14,7 @@ import SwiftSyntax
 
 /// The kind of token a node can contain. Either a token of a specific kind or a
 /// keyword with the given text.
-public enum TokenChoice: Equatable {
+public enum TokenChoice: Equatable, IdentifierConvertible {
   case keyword(Keyword)
   case token(Token)
 
@@ -25,12 +25,13 @@ public enum TokenChoice: Equatable {
     }
   }
 
-  public var varOrCaseName: TokenSyntax {
+  /// The name of this token choice as an identifier.
+  public var identifier: TokenSyntax {
     switch self {
     case .keyword(let keyword):
-      return keyword.spec.varOrCaseName
+      return keyword.spec.identifier
     case .token(let token):
-      return token.spec.varOrCaseName
+      return token.spec.identifier
     }
   }
 }
@@ -79,7 +80,7 @@ public enum ChildKind {
 
 /// A child of a node, that may be declared optional or a token with a
 /// restricted subset of acceptable kinds or texts.
-public class Child {
+public class Child: IdentifierConvertible {
   /// The name of the child.
   ///
   /// The first character of the name is always uppercase.
@@ -145,8 +146,8 @@ public class Child {
     }
   }
 
-  /// A name of this child that's suitable to be used for variable or enum case names.
-  public var varOrCaseName: TokenSyntax {
+  /// A name of this child as an identifier.
+  public var identifier: TokenSyntax {
     return .identifier(lowercaseFirstWord(name: name))
   }
 

CodeGeneration/Sources/SyntaxSupport/GrammarGenerator.swift

@@ -28,7 +28,7 @@ struct GrammarGenerator {
       if let tokenText = tokenSpec.text {
         return "`\(tokenText)`"
       } else {
-        return "`<\(tokenSpec.varOrCaseName)>`"
+        return "`<\(tokenSpec.identifier)>`"
       }
     }
   }
@@ -62,7 +62,7 @@ struct GrammarGenerator {
     return
       children
       .filter { !$0.isUnexpectedNodes }
-      .map { " - `\($0.varOrCaseName)`: \(generator.grammar(for: $0))" }
+      .map { " - `\($0.identifier)`: \(generator.grammar(for: $0))" }
       .joined(separator: "\n")
   }
 

CodeGeneration/Sources/SyntaxSupport/IdentifierConvertible.swift

@@ -0,0 +1,58 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SwiftSyntax
+
+/// Instances of a conforming type should provide an identifier to be used in code generation.
+public protocol IdentifierConvertible {
+  /// The name of the instance as an identifer.
+  var identifier: TokenSyntax {
+    get
+  }
+}
+
+public extension IdentifierConvertible {
+  /// ``identifier`` escaped as a base name suitable for call sites.
+  var baseCallName: TokenSyntax {
+    identifier.declNameOrVarCallName
+  }
+
+  /// ``identifier`` escaped as an enum case name suitable for call sites.
+  var enumCaseCallName: TokenSyntax {
+    memberCallName
+  }
+
+  /// ``identifier`` escaped as a member name suitable for call sites.
+  var memberCallName: TokenSyntax {
+    identifier.nonVarCallNameOrLabelDeclName
+  }
+
+  /// ``identifier`` escaped as an enum case name suitable for declaration sites.
+  var enumCaseDeclName: TokenSyntax {
+    identifier.declNameOrVarCallName
+  }
+
+  /// ``identifier`` escaped as a function name suitable for declaration sites.
+  var funcDeclName: TokenSyntax {
+    identifier.declNameOrVarCallName
+  }
+
+  /// ``identifier`` escaped as an argument label name suitable for declaration sites.
+  var labelDeclName: TokenSyntax {
+    identifier.nonVarCallNameOrLabelDeclName
+  }
+
+  /// ``identifier`` escaped as a variable name suitable for declaration sites.
+  var varDeclName: TokenSyntax {
+    identifier.declNameOrVarCallName
+  }
+}

CodeGeneration/Sources/SyntaxSupport/KeywordSpec.swift

@@ -12,7 +12,7 @@
 
 import SwiftSyntax
 
-public struct KeywordSpec {
+public struct KeywordSpec: IdentifierConvertible {
   /// The name of the keyword.
   public let name: String
 
@@ -29,13 +29,9 @@ public struct KeywordSpec {
   /// API generated should be marked as SPI
   public var isExperimental: Bool { experimentalFeature != nil }
 
-  /// The name of this keyword that's suitable to be used for variable or enum case names.
-  public var varOrCaseName: TokenSyntax {
-    if name == "init" {
-      return "`init`"
-    } else {
-      return TokenSyntax.identifier(name)
-    }
+  /// The name of this keyword as an identifier.
+  public var identifier: TokenSyntax {
+    TokenSyntax.identifier(name)
   }
 
   /// The attributes that should be printed on any API for the generated keyword.

CodeGeneration/Sources/SyntaxSupport/Node.swift

@@ -21,7 +21,7 @@ import SwiftSyntax
 ///    but fixed types.
 ///  - Collection nodes contains an arbitrary number of children but all those
 ///    children are of the same type.
-public class Node {
+public class Node: IdentifierConvertible {
   fileprivate enum Data {
     case layout(children: [Child], traits: [String])
     case collection(choices: [SyntaxNodeKind])
@@ -61,10 +61,9 @@ public class Node {
   /// API generated should be SPI.
   public var isExperimental: Bool { experimentalFeature != nil }
 
-  /// A name for this node that is suitable to be used as a variables or enum
-  /// case's name.
-  public var varOrCaseName: TokenSyntax {
-    return kind.varOrCaseName
+  /// A name for this node as an identifier.
+  public var identifier: TokenSyntax {
+    return kind.identifier
   }
 
   /// If this is a layout node, return a view of the node that provides access
@@ -229,7 +228,7 @@ public class Node {
     let list =
       childIn
       .map {
-        if let childName = $0.child?.varOrCaseName {
+        if let childName = $0.child?.identifier {
           // This will repeat the syntax type before and after the dot, which is
           // a little unfortunate, but it's the only way I found to get docc to
           // generate a fully-qualified type + member.

CodeGeneration/Sources/SyntaxSupport/String+Extensions.swift

@@ -23,15 +23,6 @@ extension StringProtocol {
     }
     return prefix(1).uppercased() + dropFirst()
   }
-  public var backtickedIfNeeded: String {
-    if Keyword.allCases.map(\.spec).contains(where: {
-      $0.name == self && ($0.isLexerClassified || $0.name == "Type" || $0.name == "Protocol")
-    }) {
-      return "`\(self)`"
-    } else {
-      return String(self)
-    }
-  }
 }
 
 extension String {

CodeGeneration/Sources/SyntaxSupport/SyntaxNodeKind.swift

@@ -17,7 +17,7 @@ import SwiftSyntaxBuilder
 ///
 /// Using the cases of this enum, children of syntax nodes can refer the syntax
 /// node that defines their layout.
-public enum SyntaxNodeKind: String, CaseIterable {
+public enum SyntaxNodeKind: String, CaseIterable, IdentifierConvertible {
   // Please keep this list sorted alphabetically
 
   case _canImportExpr
@@ -337,9 +337,8 @@ public enum SyntaxNodeKind: String, CaseIterable {
     }
   }
 
-  /// A name for this node that is suitable to be used as a variables or enum
-  /// case's name.
-  public var varOrCaseName: TokenSyntax {
+  /// A name for this node as an identifier.
+  public var identifier: TokenSyntax {
     return .identifier(rawValue)
   }
 

CodeGeneration/Sources/SyntaxSupport/TokenSpec.swift

@@ -13,16 +13,16 @@
 import SwiftSyntax
 
 /// Represents the specification for a Token in the TokenSyntax file.
-public struct TokenSpec {
+public struct TokenSpec: IdentifierConvertible {
   public enum Kind {
     case punctuation
     /// The `keyword` TokenKind that contains the actual keyword as an associated value
     case keyword
     case other
   }
 
-  /// The name of the token, suitable for use in variable or enum case names.
-  public let varOrCaseName: TokenSyntax
+  /// The name of the token as an identifier.
+  public let identifier: TokenSyntax
 
   /// The experimental feature the token is part of, or `nil` if this isn't
   /// for an experimental feature.
@@ -66,7 +66,7 @@ public struct TokenSpec {
     text: String? = nil,
     kind: Kind
   ) {
-    self.varOrCaseName = .identifier(name)
+    self.identifier = .identifier(name)
     self.experimentalFeature = experimentalFeature
     self.nameForDiagnostics = nameForDiagnostics
     self.text = text

CodeGeneration/Sources/SyntaxSupport/Utils.swift

@@ -69,14 +69,29 @@ extension Collection {
   }
 }
 
+private extension Keyword {
+  static let backticksNeeded: Set<String> = Set(
+    Keyword.allCases.map(\.spec).filter {
+      $0.isLexerClassified || $0.name == "Type" || $0.name == "Protocol"
+    }.map(\.name)
+  )
+}
+
 extension TokenSyntax {
-  public var backtickedIfNeeded: TokenSyntax {
-    if Keyword.allCases.map(\.spec).contains(where: {
-      $0.name == self.description && ($0.isLexerClassified || $0.name == "Type" || $0.name == "Protocol")
-    }) {
+  public var declNameOrVarCallName: Self {
+    if Keyword.backticksNeeded.contains(self.description) {
       return "`\(self)`"
     } else {
       return self
     }
   }
+
+  public var nonVarCallNameOrLabelDeclName: Self {
+    switch self.tokenKind {
+    case .keyword(.`init`), .identifier("init"):
+      return "`init`"
+    default:
+      return self
+    }
+  }
 }

CodeGeneration/Sources/Utils/SyntaxBuildableChild.swift

@@ -72,12 +72,12 @@ extension Child {
       return buildableType.defaultValue
     }
     if token.text != nil {
-      return ExprSyntax(".\(token.varOrCaseName)Token()")
+      return ExprSyntax(".\(token.identifier)Token()")
     }
     if case .token(let choices, _, _) = kind,
       case .keyword(let keyword) = choices.only
     {
-      return ExprSyntax(".\(token.varOrCaseName)(.\(keyword.spec.varOrCaseName))")
+      return ExprSyntax(".\(token.memberCallName)(.\(keyword.spec.memberCallName))")
     }
     return nil
   }