IncrementIntegers.swift

// Copyright 2018 Google LLC.
// SPDX-License-Identifier: Apache-2.0

import Foundation
import SwiftSyntax

public class IncrementIntegers: SyntaxRewriter {
  public override func visit(_ token: TokenSyntax) -> Syntax {
    guard case .integerLiteral(let intToken) = token.tokenKind else {
      return token
    }

    guard let integerValue = Int(intToken) else {
      return token
    }

    let newValue = integerValue + 1

    let newKind = TokenKind.integerLiteral(newValue.description)

    return token.withKind(newKind)
  }
}

func main() throws {
  let testURL = URL(fileURLWithPath: CommandLine.arguments[1])
  let testFile = try SourceFileSyntax.parse(testURL)

  let incrementer = IncrementIntegers()
  let rewritten = incrementer.visit(testFile)

  print(rewritten)
}

do {
  try main()
} catch {
  print("error: \(error)")
  exit(-1)
}