anchor.diff:          original
           |> fillSnippets commitHash
           |> insertGithubCommit commitHash
  -        |> insertGitDiff commitHash
         write (outFile, contents))
     | Some changedFile ->
       let original = File.ReadAllLines changedFile.FullName |> List.ofArray
  
positive.code:           original
            |> fillSnippets commitHash
            |> insertGithubCommit commitHash
            |> insertGitDiff commitHash
        | None ->
          original
      write (outFile, contents)
  
negative.code:   |> insertTips
    
  let insertGithubCommit commit code = 
    sprintf "Show code from this section on [GitHub](https://github.com/%s/%s/commit/%s)"
            githubAccount
            githubRepo
            commit
    |> List.singleton
    |> List.append ["";"---";""]
    |> List.append code
  
  let generate (changedFile : FileInfo option) =
    let hashLen = 40
  