Update the AddBlocker implementation and clean up a few things

mayoff · Feb 1, 2023 · 3f134cc · 3f134cc
1 parent d1e7fbe
commit 3f134cc
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Showing 3 changed files with 65 additions and 74 deletions.
diff --git a/MacroExamples/main.swift b/MacroExamples/main.swift
@@ -15,24 +15,24 @@ func blockAdd() {
   print(#addBlocker(x * y + z))
 }
 
-func produceWarning() {
+func warningAndError() {
   #myWarning("remember to pass a string literal here")
-}
-// Uncomment to get an error out of the macro.
-//   let text = "oops"
-//   #myWarning(text)
 
+  // Uncomment to get an error out of the macro.
+  // let text = "oops"
+  // #myWarning(text)
+}
 
 struct Font: ExpressibleByFontLiteral {
   init(fontLiteralName: String, size: Int, weight: MacroExamplesLib.FontWeight) {
   }
 }
 
 func testFontLiteral() {
-  let font: Font = #fontLiteral(name: "Comic Sans", size: 14, weight: .thin)
+  let _: Font = #fontLiteral(name: "Comic Sans", size: 14, weight: .thin)
 }
 
 testStringify()
 blockAdd()
-produceWarning()
+warningAndError()
 testFontLiteral()
diff --git a/MacroExamplesPlugin/AddBlocker.swift b/MacroExamplesPlugin/AddBlocker.swift
@@ -13,95 +13,86 @@ extension SimpleDiagnosticMessage: FixItMessage {
   var fixItID: MessageID { diagnosticID }
 }
 
-class AddVisitor: SyntaxRewriter {
-  var diagnostics: [Diagnostic] = []
+public struct AddBlocker: ExpressionMacro {
+  class AddVisitor: SyntaxRewriter {
+    var diagnostics: [Diagnostic] = []
 
-  override func visit(
-    _ node: InfixOperatorExprSyntax
-  ) -> ExprSyntax {
-    if let binOp = node.operatorOperand.as(BinaryOperatorExprSyntax.self) {
-      if binOp.operatorToken.text == "+" {
-        let messageID = MessageID(domain: "silly", id: "addblock")
-        diagnostics.append(
-          Diagnostic(
-            node: Syntax(node.operatorOperand),
-            message: SimpleDiagnosticMessage(
-              message: "blocked an add; did you mean to subtract?",
-              diagnosticID: messageID,
-              severity: .warning
-            ),
-            highlights: [
-              Syntax(node.leftOperand.with(\.leadingTrivia, []).with(\.trailingTrivia, [])),
-              Syntax(node.rightOperand.with(\.leadingTrivia, []).with(\.trailingTrivia, []))
-            ],
-            fixIts: [
-              FixIt(
-                message: SimpleDiagnosticMessage(
-                  message: "use '-'",
-                  diagnosticID: messageID,
-                  severity: .error
-                ),
-                changes: [
-                  FixIt.Change.replace(
-                    oldNode: Syntax(binOp.operatorToken.with(\.leadingTrivia, []).with(\.trailingTrivia, [])),
-                    newNode: Syntax(
-                      TokenSyntax(
-                        .binaryOperator("-"),
-                        presence: .present
+    override func visit(
+      _ node: InfixOperatorExprSyntax
+    ) -> ExprSyntax {
+      if let binOp = node.operatorOperand.as(BinaryOperatorExprSyntax.self) {
+        if binOp.operatorToken.text == "+" {
+          let messageID = MessageID(domain: "silly", id: "addblock")
+          diagnostics.append(
+            Diagnostic(
+              node: Syntax(node.operatorOperand),
+              message: SimpleDiagnosticMessage(
+                message: "blocked an add; did you mean to subtract?",
+                diagnosticID: messageID,
+                severity: .warning
+              ),
+              highlights: [
+                Syntax(node.leftOperand),
+                Syntax(node.rightOperand)
+              ],
+              fixIts: [
+                FixIt(
+                  message: SimpleDiagnosticMessage(
+                    message: "use '-'",
+                    diagnosticID: messageID,
+                    severity: .error
+                  ),
+                  changes: [
+                    FixIt.Change.replace(
+                      oldNode: Syntax(binOp.operatorToken),
+                      newNode: Syntax(
+                        TokenSyntax(
+                          .binaryOperator("-"),
+                          leadingTrivia: binOp.operatorToken.leadingTrivia,
+                          trailingTrivia: binOp.operatorToken.trailingTrivia,
+                          presence: .present
+                        )
                       )
                     )
-                  )
-                ]
-              ),
-            ]
+                  ]
+                ),
+              ]
+            )
           )
-        )
 
-        return ExprSyntax(
-          node.with(
-            \.operatorOperand,
-             ExprSyntax(
-              binOp.with(
-                \.operatorToken,
-                 binOp.operatorToken.withKind(.binaryOperator("-"))
+          return ExprSyntax(
+            node.with(
+              \.operatorOperand,
+              ExprSyntax(
+                binOp.with(
+                  \.operatorToken,
+                  binOp.operatorToken.withKind(.binaryOperator("-"))
+                )
               )
-             )
+            )
           )
-        )
+        }
       }
-    }
 
-    return ExprSyntax(node)
+      return ExprSyntax(node)
+    }
   }
- }
 
-public struct AddBlocker: ExpressionMacro {
   public static func expansion(
     of node: some FreestandingMacroExpansionSyntax,
     in context: some MacroExpansionContext
   ) throws -> ExprSyntax {
     guard let argument = node.argumentList.first?.expression else {
-      let messageID = MessageID(domain: "example", id: "missingArg")
-      throw SimpleDiagnosticMessage(message: "missing argument",
-                                    diagnosticID: messageID,
-                                    severity: .error)
+      fatalError("boom")
     }
 
-    let opTable = OperatorTable.standardOperators
-    let foldedArgument = opTable.foldAll(argument) { error in
-      context.diagnose(error.asDiagnostic)
-    }
-
-    // Link the folded argument back into the tree.
-    let node = node.with(\.argumentList, node.argumentList.replacing(childAt: 0, with: node.argumentList.first!.with(\.expression, foldedArgument.as(ExprSyntax.self)!)))
-
     let visitor = AddVisitor()
     let result = visitor.visit(Syntax(node))
 
     for diag in visitor.diagnostics {
       context.diagnose(diag)
     }
 
-    return result.as(MacroExpansionExprSyntax.self)!.argumentList.first!.expression
+    return result.asProtocol(FreestandingMacroExpansionSyntax.self)!.argumentList.first!.expression
   }
 }
diff --git a/MacroExamplesPlugin/WarningMacro.swift b/MacroExamplesPlugin/WarningMacro.swift
@@ -39,5 +39,5 @@ enum CustomError: Error, CustomStringConvertible {
      )
 
      return "()"
-   }
- }
+  }
+}
-Original file line number
+Diff line change
@@ Expand Up / @@ -39,5 +39,5 @@ enum CustomError: Error, CustomStringConvertible { @@
          )
          return "()"
-       }
-     }
+      }
+    }