Why is .>>. giving an F# error

[jcoder58]

First time Farkle (6.5.1) user. Why am I getting a compile error in the following Farkle grammar?

open Farkle.Builder
module rec Grammar =
let hex_quad = "hex_quad" ||= [
    !@ hexadecimal_digit .>>. hexadecimal_digit .>>. hexadecimal_digit .>>. hexadecimal_digit
]
let universal_character_name = "universal_character_name" ||= [
    !& @"\u" .>>. hex_quad
   // Error: None of the types 'ProductionBuilder, DesigntimeFarkle<'a>' support the operator '.>>.'	
    !& "\U" .>>. hex_quad .>>. hex_quad
]

[teo-tsirpanis]

Hi @jcoder58 and thanks for using Farkle!

Can you provide a more complete example? I cannot build the attached snippet. Here's some feedback from what I can understand:

• Are you using universal_character_name as part of a string? The Terminals.string and stringEx function might be of interest to you and it is much more performant.
• At the end of building a production, you have to finish it with the => operator.

Let me know if you have more questions.

[teo-tsirpanis]

@jcoder58 I got an email that you sent a reply which looks like you later deleted. Does that mean that your problem is solved?