F# app model

[wli3]

It would be nice to have F# parser like this Haskell library https://github.com/pcapriotti/optparse-applicative . I like that you can just pattern match the result. And it looks cool.

In F# it might look like the following when use (almost real code). Using notion from https://github.com/fsprojects/FSharpPlus

type Sample =
    { hello : string
      quiet : bool
      enthusiasm : int }

let currySample (hello : string) (quiet : bool) (enthusiasm : int) =
        { hello = hello
          quiet = quiet
          enthusiasm = enthusiasm }

let parser =
        currySample 
        <!> Option(Aliases [ "--hello"; "-h" ] 
            + HelpDetail "description" 
            + Argument ExactlyOne "TARGET") 
        <*> Option(Aliases [ "-q" ] 
            + HelpDetail "description" 
            + Argument Zero) 
        <*> Option(Aliases [ "--enthusiasm" ] 
            + HelpDetail "description" 
            + Argument ExactlyOne "INT")

let result : Sample = runParser parser "--hello Bob -q --enthusiasm 3"

To add in subcommand, Sample need to be a union and it should use alternative to combine parser https://github.com/pcapriotti/optparse-applicative#alternative

Problems:

1. Is there a genetic way to curry Record type? Or we may need to use Tuple.
2. How to fit Argument? Just by position could be fine. During config, the name of the Record field is not used.
   ...
   ...

[jonsequitur]

@cartermp