Merge pull request #1155 from DougGregor/simplify-syntax-macros-api

Author: DougGregor

Package.swift

@@ -150,7 +150,7 @@ let package = Package(
     ),
     .executableTarget(
       name: "swift-parser-cli",
-      dependencies: ["SwiftDiagnostics", "SwiftSyntax", "SwiftParser", "SwiftParserDiagnostics", "SwiftOperators", "_SwiftSyntaxMacros",
+      dependencies: ["SwiftDiagnostics", "SwiftSyntax", "SwiftParser", "SwiftParserDiagnostics", "SwiftOperators",
                      .product(name: "ArgumentParser", package: "swift-argument-parser")]
     ),
     .testTarget(name: "IDEUtilsTest", dependencies: ["_SwiftSyntaxTestSupport", "SwiftParser", "SwiftSyntax", "IDEUtils"]),

Sources/_SwiftSyntaxMacros/CMakeLists.txt

@@ -10,8 +10,6 @@ add_swift_host_library(_SwiftSyntaxMacros
   ExpressionMacro.swift
   Macro.swift
   MacroExpansionContext.swift
-  MacroSystem+Builtin.swift
-  MacroSystem+Examples.swift
   MacroSystem.swift
   Syntax+MacroEvaluation.swift
 )

Sources/_SwiftSyntaxMacros/MacroSystem+Builtin.swift

@@ -14,7 +14,7 @@ import SwiftDiagnostics
 import SwiftSyntax
 
 /// Describes the kinds of errors that can occur within a macro system.
-public enum MacroSystemError: Error {
+enum MacroSystemError: Error {
   /// Indicates that a macro with the given name has already been defined.
   case alreadyDefined(new: Macro.Type, existing: Macro.Type)
 
@@ -36,16 +36,16 @@ public enum MacroSystemError: Error {
 }
 
 /// A system of known macros that can be expanded syntactically
-public struct MacroSystem {
+struct MacroSystem {
   var macros: [String: Macro.Type] = [:]
 
   /// Create an empty macro system.
-  public init() {}
+  init() {}
 
   /// Add a macro to the system.
   ///
   /// Throws an error if there is already a macro with this name.
-  public mutating func add(_ macro: Macro.Type, name: String) throws {
+  mutating func add(_ macro: Macro.Type, name: String) throws {
     if let knownMacro = macros[name] {
       throw MacroSystemError.alreadyDefined(new: macro, existing: knownMacro)
     }
@@ -54,7 +54,7 @@ public struct MacroSystem {
   }
 
   /// Look for a macro with the given name.
-  public func lookup(_ macroName: String) -> Macro.Type? {
+  func lookup(_ macroName: String) -> Macro.Type? {
     return macros[macroName]
   }
 }
@@ -101,20 +101,28 @@ class MacroApplication: SyntaxRewriter {
   }
 }
 
-extension MacroSystem {
-  /// Expand all macros encountered within the given syntax tree.
-  ///
-  /// - Parameter node: The syntax node in which macros will be evaluated.
-  /// - Parameter context: The context in which macros are evaluated.
-  /// - Returns: the syntax tree with all macros evaluated.
-  public func evaluateMacros<Node: SyntaxProtocol>(
-    node: Node,
+extension SyntaxProtocol {
+  /// Expand all uses of the given set of macros within this syntax
+  /// node.
+  public func expand(
+    macros: [String: Macro.Type],
     in context: inout MacroExpansionContext
   ) -> Syntax {
+    // Build the macro system.
+    var system = MacroSystem()
+    for (macroName, macroType) in macros {
+      try! system.add(macroType, name: macroName)
+    }
+
     let applier = MacroApplication(
-      macroSystem: self,
+      macroSystem: system,
       context: context
     )
-    return applier.visit(Syntax(node))
+
+    defer {
+      context = applier.context
+    }
+
+    return applier.visit(Syntax(self))
   }
 }

Sources/_SwiftSyntaxMacros/MacroSystem+Examples.swift

@@ -95,7 +95,7 @@ extension Syntax {
   /// Determine the name of the macro that is evaluated by this syntax node,
   /// if indeed it is a macro evaluation. For example, "#stringify(x)" has the
   /// name "stringify".
-  public var evaluatedMacroName: String? {
+  var evaluatedMacroName: String? {
     switch self.as(SyntaxEnum.self) {
     case .macroExpansionDecl(let expansion):
       return expansion.macro.text
@@ -114,7 +114,7 @@ extension Syntax {
   /// This operation only makes sense when `evaluatedMacroName` produces a
   /// non-nil value, indicating that this syntax node is a macro evaluation of
   /// some kind.
-  public func evaluateMacro(
+  func evaluateMacro(
     with macroSystem: MacroSystem,
     context: inout MacroExpansionContext
   ) -> Syntax {

Sources/_SwiftSyntaxMacros/MacroSystem.swift

@@ -12,7 +12,6 @@
 
 import SwiftDiagnostics
 import SwiftSyntax
-@_spi(Testing) import _SwiftSyntaxMacros
 import SwiftParser
 import SwiftParserDiagnostics
 import SwiftOperators
@@ -82,7 +81,6 @@ class SwiftParserCli: ParsableCommand {
     subcommands: [
       PrintDiags.self,
       PrintTree.self,
-      ExpandMacros.self,
       Reduce.self,
       VerifyRoundTrip.self,
     ]
@@ -219,51 +217,6 @@ class PrintTree: ParsableCommand {
   }
 }
 
-class ExpandMacros: ParsableCommand {
-  static var configuration = CommandConfiguration(
-    commandName: "expand-macros",
-    abstract: "Expand example macros and print the result source code"
-  )
-
-  required init() {}
-
-  @Argument(help: "The source file that should be parsed; if omitted, use stdin")
-  var sourceFile: String
-
-  @Flag(name: .long, help: "Perform sequence folding with the standard operators")
-  var foldSequences: Bool = false
-
-  func run() throws {
-    let source = try getContentsOfSourceFile(at: sourceFile)
-
-    source.withUnsafeBufferPointer { sourceBuffer in
-      let tree = Parser.parse(source: sourceBuffer)
-
-      let resultTree: Syntax
-      if foldSequences {
-        resultTree = foldAllSequences(tree).0
-      } else {
-        resultTree = Syntax(tree)
-      }
-
-      var context = MacroExpansionContext(
-        moduleName: "MyModule",
-        fileName: self.sourceFile.withoutPath()
-      )
-      var diags = ParseDiagnosticsGenerator.diagnostics(for: tree)
-      let transformedTree = MacroSystem.exampleSystem.evaluateMacros(
-        node: resultTree,
-        in: &context
-      )
-
-      diags.append(contentsOf: context.diagnostics)
-
-      print(transformedTree)
-      print(DiagnosticsFormatter.annotatedSource(tree: tree, diags: diags))
-    }
-  }
-}
-
 class Reduce: ParsableCommand {
   static var configuration = CommandConfiguration(
     commandName: "reduce",