--help switch throwing exception

[melston]

I have a simple F# program that works for all defined command-line options. However, when I run the application with --help I get an exception:

Unhandled Exception: System.Exception: CommandLine.Error[]
   at Program.main(String[] argv) in D:\Projects\Test\FSharp\StoryLib\StoryUpdate\Program.fs:line 46

This line is the last line in the match of the parsing result.

In addition, using the two match options shown in the docs I get a warning about an incomplete pattern match on the expression. It appears that there should be more than

    match args with 
    | :? Parsed<Options> as parsed -> doActions parsed.Value
    | :? NotParsed<Options> as notParsed -> failwith (notParsed.Errors |> string)
    // should there be a third option here?

[WallaceKelly]

The --help and --version options are treated as NotParsed. But there are extension methods for the errors to detect if the NotParsed result included a --help or --version.

Here is what you need...

match args with 
| :? Parsed<Options> as parsed -> doActions parsed.Value
| :? NotParsed<'a> as notParsed when notParsed.Errors.IsHelp() -> ()
| :? NotParsed<'a> as notParsed when notParsed.Errors.IsVersion() -> ()
| :? NotParsed<Options> as notParsed -> failwith (notParsed.Errors |> string)

[moh-hassan]

The modified demo will be available in the next Release 2.7