anchor.diff:    /// Recognizes a SceneHeading (prefixed with INT/EXT, etc. or a single period)
     let (|SceneHeading|_|) = function
       //TODO: why doesn't this work? 
  -//    | String.StartsWithAny [ "INT"; "EXT"; "EST"; "INT./EXT."; "INT/EXT"; "I/E"; ] heading:string :: rest ->
  +//    | String.StartsWithAny [ "INT"; "EXT"; "EST"; "INT./EXT."; "INT/EXT"; "I/E" ] heading:string :: rest ->
   //       Some(heading.Trim(), rest)
       | String.StartsWith "." heading:string :: rest ->
          Some(heading.Trim(), rest) 
       | rest ->
          None
  -
   
     /// Recognizes a Lyric (prefixed with ~)
     let (|Lyric|_|) = function
  
positive.code: 
  /// Representation of a Fountain document - the representation of Blocks
  /// uses an F# discriminated union type and so is best used from F#.
  type FountainDocument(blocks) =
    /// Returns a list of blocks in the document
    member x.Blocks : FountainBlocks = blocks
    /// Returns a dictionary containing explicitly defined links
  
  
  /// Static class that provides methods for formatting 
  
negative.code:         Some(lyric.Trim(), rest)
      | rest ->
          None
  
    /// Splits input into lines until whitespace
    let (|LinesUntilListOrWhite|) = 
  