Remove backticks when creating Identifier

Added a new Identifier type which contains a name property

This name property contains a sanitized version of the TokenSyntax's
text property which for now only consists of trimming backticks

Author: adammcarter

Sources/SwiftSyntax/Identifier.swift

@@ -0,0 +1,28 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+/// An abstraction for sanitized values on a token.
+public struct Identifier {
+  /// The sanitized `text` of a token.
+  public let name: String
+
+  public init(_ token: TokenSyntax) {
+    let text = token.text
+
+    self.name =
+      if text.contains("`") {
+        String(text.trimmingCharacters("`"))
+      } else {
+        text
+      }
+  }
+}

Sources/SwiftSyntax/Utils.swift

@@ -120,3 +120,38 @@ extension RawUnexpectedNodesSyntax {
     self.init(raw: raw)
   }
 }
+
+extension String {
+  func removingCharactersStartingWith(_ charactersToTrim: String) -> Substring {
+    var startCharactersToDrop = 0
+
+    for character in self {
+      if charactersToTrim.contains(character) {
+        startCharactersToDrop += 1
+      } else {
+        break
+      }
+    }
+
+    return dropFirst(startCharactersToDrop)
+  }
+
+  func removingCharactersEndingWith(_ charactersToTrim: String) -> Substring {
+    var endCharactersToDrop = 0
+
+    for character in reversed() {
+      if charactersToTrim.contains(character) {
+        endCharactersToDrop += 1
+      } else {
+        break
+      }
+    }
+
+    return dropLast(endCharactersToDrop)
+  }
+
+  func trimmingCharacters(_ characters: String) -> Substring {
+    String(removingCharactersStartingWith(characters))
+      .removingCharactersEndingWith(characters)
+  }
+}

Tests/SwiftSyntaxTest/IdentifierTests.swift

@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+import XCTest
+
+class IdentifierTests: XCTestCase {
+  public func testInit() {
+    let basicToken = TokenSyntax(stringLiteral: "sometoken")
+    XCTAssertEqual(Identifier(basicToken).name, "sometoken")
+
+    let backtickedToken = TokenSyntax(stringLiteral: "`backtickedtoken`")
+    XCTAssertEqual(Identifier(backtickedToken).name, "backtickedtoken")
+
+    let multiBacktickedToken = TokenSyntax(stringLiteral: "```backtickedtoken```")
+    XCTAssertEqual(Identifier(multiBacktickedToken).name, "backtickedtoken")
+  }
+}