Recommendation for Command Line Parser

[TheRealPiotrP]

Can someone make a recommendation on what CLI parser to use? some options:

• ASP.NET
• CoreFx
• docopt

[Eilon]

Do we need managed or unmanaged or both?

For managed code, DNX has one that is used in several utilities.

• CommandLineUtils library: https://github.com/aspnet/dnx/tree/dev/src/Microsoft.Extensions.CommandLineUtils.Sources
• Example setup for dnu command line utility: https://github.com/aspnet/dnx/blob/219871c6063d00f8297eeafe93266f1048f59a45/src/Microsoft.Dnx.Tooling/Program.cs#L55-L84
• Example command implementations for dnu: https://github.com/aspnet/dnx/tree/219871c6063d00f8297eeafe93266f1048f59a45/src/Microsoft.Dnx.Tooling/ConsoleCommands

And it generates output like this:

C:\Users\elipton>dnu
Microsoft .NET Development Utility Clr-x86-1.0.0-rc1-15798

Usage: dnu [options] [command]

Options:
  -v|--verbose  Show verbose output
  -?|-h|--help  Show help information
  --version     Show version information

Commands:
  build             Produce assemblies for the project in given directory
  clear-http-cache  Clears the package cache.
  commands          Commands related to managing application commands (install, uninstall)
  feeds             Commands related to managing package feeds currently in use
  install           Install the given dependency
  list              Print the dependencies of a given project
  pack              Build NuGet packages for the project in given directory
  packages          Commands related to managing local and remote packages folders
  publish           Publish application for deployment
  restore           Restore packages
  wrap              Wrap a csproj/assembly into a project.json, which can be referenced by project.json files

Use "dnu [command] --help" for more information about a command.

And:

C:\Users\elipton>dnu build --help


Usage: dnu build [arguments] [options]

Arguments:
  [projects]  One or more projects build. If not specified, the project in the current directory will be used.

Options:
  --framework <TARGET_FRAMEWORK>   A list of target frameworks to build.
  --configuration <CONFIGURATION>  A list of configurations to build.
  --out <OUTPUT_DIR>               Output directory
  --quiet                          Do not show output such as dependencies in use
  -?|-h|--help                     Show help information

[ahsonkhan]

The above mentioned command line utility is what is currently being used.
Another alternative is the command line utility as part of corefx:
https://github.com/dotnet/corefxlab/tree/master/src/System.CommandLine

[KrzysztofCwalina]

The corefxlab one does not use reflection, so [edit: might be] better for AOT

[Eilon]

Hmm does the DNX one use reflection? I haven't dug into the code a whole lot but I didn't see any usage. Might have missed it.

[analogrelay]

The DNX one doesn't use reflection either.

[bricelam]

+1 for System.CommandLine; It's a lot like DNX's CommandLineUtils, but better in my opinion. 😈

[agocke]

System.CommandLine is already being used in dotnet-compile* -- I think it's worked pretty well. I hit issues with DNX command line since it's currently source-only and it also ties execution semantics of the program to command line parsing (i.e., app.Execute(args)).

[analogrelay]

@bricelam SCANDAL! TRAITOR! HEATHEN! Nah, sounds good to me :). Let's move to System.CommandLine

[TheRealPiotrP]

@krwq can you pick this up next?

[analogrelay]

It seems we've been transitioning to System.CommandLine. Should we just get everything switched over and remove the DNX parser?

[davidfowl]

Yes and fix the bugs in system.commandline

[Eilon]

@davidfowl anything specific?

[davidfowl]

Might just be a bug in run right now but you can't flow arguments to the application. i.e.

dotnet run --blag won't work

[TheBlueSky]

Now that dotnet is going to use System.CommandLine, is it safe to assume that System.CommandLine will make it to corefx repository?

[blackdwarf]

Guys, since we have started using the System.CommandLine, I will close this issue. Please reopen if needed.

/cc @piotrpMSFT