Stop parsing into PoundColumnExprSyntax, add a macro instead

Author: DougGregor

Sources/SwiftParser/Expressions.swift

@@ -1053,12 +1053,6 @@ extension Parser {
         poundLine: tok,
         arena: self.arena
       ))
-    case (.poundColumnKeyword, let handle)?:
-      let tok = self.eat(handle)
-      return RawExprSyntax(RawPoundColumnExprSyntax(
-        poundColumn: tok,
-        arena: self.arena
-      ))
     case (.__column__Keyword, let handle)?:
       let tok = self.eat(handle)
       return RawExprSyntax(RawPoundColumnExprSyntax(

Sources/SwiftParser/Lexer.swift

@@ -1543,7 +1543,6 @@ extension Lexer.Cursor {
     case "file": kind = .poundFileKeyword
     case "fileID": kind = .poundFileIDKeyword
     case "filePath": kind = .poundFilePathKeyword
-    case "column": kind = .poundColumnKeyword
     case "function": kind = .poundFunctionKeyword
     case "dsohandle": kind = .poundDsohandleKeyword
     case "assert": kind = .poundAssertKeyword

Sources/SwiftParser/RawTokenKindSubset.swift

@@ -739,7 +739,6 @@ enum PrimaryExpressionStart: RawTokenKindSubset {
   case period
   case pound
   case poundColorLiteralKeyword
-  case poundColumnKeyword
   case poundDsohandleKeyword
   case poundFileIDKeyword
   case poundFileKeyword
@@ -778,7 +777,6 @@ enum PrimaryExpressionStart: RawTokenKindSubset {
     case .period: self = .period
     case .pound: self = .pound
     case .poundColorLiteralKeyword: self = .poundColorLiteralKeyword
-    case .poundColumnKeyword: self = .poundColumnKeyword
     case .poundDsohandleKeyword: self = .poundDsohandleKeyword
     case .poundFileIDKeyword: self = .poundFileIDKeyword
     case .poundFileKeyword: self = .poundFileKeyword
@@ -820,7 +818,6 @@ enum PrimaryExpressionStart: RawTokenKindSubset {
     case .period: return .period
     case .pound: return .pound
     case .poundColorLiteralKeyword: return .poundColorLiteralKeyword
-    case .poundColumnKeyword: return .poundColumnKeyword
     case .poundDsohandleKeyword: return .poundDsohandleKeyword
     case .poundFileIDKeyword: return .poundFileIDKeyword
     case .poundFileKeyword: return .poundFileKeyword

Sources/SwiftSyntaxMacros/MacroSystem+Examples.swift

@@ -2,6 +2,19 @@ import SwiftSyntax
 import SwiftSyntaxBuilder
 
 // Macros used for testing purposes
+struct ColumnMacro: ExpressionMacro {
+  static var name: String { "column" }
+
+  static func apply(
+    _ macro: MacroExpansionExprSyntax, in context: MacroEvaluationContext
+  ) -> MacroResult<ExprSyntax> {
+    let line = macro.startLocation(
+      converter: context.sourceLocationConverter
+    ).column ?? 0
+    return .init("\(line)")
+  }
+}
+
 struct LineMacro: ExpressionMacro {
   static var name: String { "line" }
 
@@ -47,6 +60,7 @@ struct ColorLiteral: ExpressionMacro {
 extension MacroSystem {
   public static var exampleSystem: MacroSystem {
     var macroSystem = MacroSystem()
+    try! macroSystem.add(ColumnMacro.self)
     try! macroSystem.add(LineMacro.self)
     try! macroSystem.add(Stringify.self)
     try! macroSystem.add(ColorLiteral.self)

Tests/SwiftSyntaxMacrosTest/MacroSystemTests.swift

@@ -12,6 +12,7 @@ final class MacroSystemTests: XCTestCase {
       let a = (#line)
       let b = #stringify(x + y)
       #myColorLiteral(red: 0.5, green: 0.5, blue: 0.25, alpha: 1.0)
+      let c = #column
       """
     let converter = SourceLocationConverter(file: "test.swift", tree: sf)
     let context = MacroEvaluationContext(sourceLocationConverter: converter)
@@ -25,6 +26,7 @@ final class MacroSystemTests: XCTestCase {
       let a = (2)
       let b = (x + y, #"x + y"#)
       .init(red: 0.5, green: 0.5, blue: 0.25, alpha: 1.0)
+      let c = 9
       """
     )
   }