How to implement countable flags? Ref. -vvv for "triple verbosity"

[x10an14]

I'm not sure whether or not what I describe is part of the GNU getopt standard.

But ssh is a good example for what I'm trying to do.

Anyone using Github can perform the following (as long as they've set-up SSH keys):

-> $ ssh -T git@github.com
Hi x10an14! You've successfully authenticated, but GitHub does not provide shell access.

And....

Long SSH example output

-> $ ssh -Tvv git@github.com
OpenSSH_7.6p1 Ubuntu-4ubuntu0.3, OpenSSL 1.0.2n  7 Dec 2017
debug1: Reading configuration data /home/x10an14/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "github.com" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to github.com [140.82.118.4] port 22.
debug1: Connection established.
debug1: identity file /home/x10an14/.ssh/id_rsa type 0
debug1: key_load_public: No such file or directory
debug1: identity file /home/x10an14/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/x10an14/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/x10an14/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/x10an14/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/x10an14/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/x10an14/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/x10an14/.ssh/id_ed25519-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.3
debug1: Remote protocol version 2.0, remote software version babeld-003ebee6
debug1: no match: babeld-003ebee6
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to github.com:22 as 'git'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: ssh-rsa-cert-v01@openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com,zlib
debug2: compression stoc: none,zlib@openssh.com,zlib
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256
debug2: host key algorithms: ssh-dss,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr,aes256-cbc,aes192-cbc,aes128-cbc
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr,aes256-cbc,aes192-cbc,aes128-cbc
debug2: MACs ctos: hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib,zlib@openssh.com
debug2: compression stoc: none,zlib,zlib@openssh.com
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: rsa-sha2-512
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ssh-rsa SHA256:nThbg6kXUpJWGl7E1IGOCspRomTxdCARLviKw6E5SY8
debug1: Host 'github.com' is known and matches the RSA host key.
debug1: Found key in /home/x10an14/.ssh/known_hosts:3
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey after 134217728 blocks
debug2: key: /home/x10an14/.ssh/id_rsa (0x562872240bf0), agent
debug2: key: /home/x10an14/.ssh/id_dsa ((nil))
debug2: key: /home/x10an14/.ssh/id_ecdsa ((nil))
debug2: key: /home/x10an14/.ssh/id_ed25519 ((nil))
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-rsa,rsa-sha2-512,rsa-sha2-256,ssh-dss>
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering public key: RSA SHA256:ll1aqkyno22aTX/zV1FtKkZ/id+7h8vn/uWY1bDWXbo /home/x10an14/.ssh/id_rsa
debug2: we sent a publickey packet, wait for reply
debug1: Server accepts key: pkalg ssh-rsa blen 1047
debug2: input_userauth_pk_ok: fp SHA256:ll1aqkyno22aTX/zV1FtKkZ/id+7h8vn/uWY1bDWXbo
debug1: Authentication succeeded (publickey).
Authenticated to github.com ([140.82.118.4]:22).
debug1: channel 0: new [client-session]
debug2: channel 0: send open
debug1: Entering interactive session.
debug1: pledge: network
debug2: channel_input_open_confirmation: channel 0: callback start
debug2: fd 3 setting TCP_NODELAY
debug2: client_session2_setup: id 0
debug1: Sending environment.
debug1: Sending env LC_MEASUREMENT = nb_NO.UTF-8
debug2: channel 0: request env confirm 0
debug1: Sending env LC_PAPER = nb_NO.UTF-8
debug2: channel 0: request env confirm 0
debug1: Sending env LC_MONETARY = nb_NO.UTF-8
debug2: channel 0: request env confirm 0
debug1: Sending env LANG = en_US.UTF-8
debug2: channel 0: request env confirm 0
debug1: Sending env LC_NAME = nb_NO.UTF-8
debug2: channel 0: request env confirm 0
debug1: Sending env LC_ADDRESS = nb_NO.UTF-8
debug2: channel 0: request env confirm 0
debug1: Sending env LC_NUMERIC = nb_NO.UTF-8
debug2: channel 0: request env confirm 0
debug1: Sending env LC_TELEPHONE = nb_NO.UTF-8
debug2: channel 0: request env confirm 0
debug1: Sending env LC_IDENTIFICATION = nb_NO.UTF-8
debug2: channel 0: request env confirm 0
debug2: channel 0: request shell confirm 1
debug2: channel_input_open_confirmation: channel 0: callback done
debug2: channel 0: open confirm rwindow 32000 rmax 35000
debug2: channel_input_status_confirm: type 99 id 0
debug2: shell request accepted on channel 0
debug2: channel 0: rcvd ext data 89
debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
debug2: channel 0: rcvd eof
debug2: channel 0: output open -> drain
debug2: channel 0: rcvd close
debug2: channel 0: close_read
debug2: channel 0: input open -> closed
debug2: channel 0: obuf_empty delayed efd 7/(89)
Hi x10an14! You've successfully authenticated, but GitHub does not provide shell access.
debug2: channel 0: written 89 to efd 7
debug2: channel 0: obuf empty
debug2: channel 0: close_write
debug2: channel 0: output drain -> closed
debug2: channel 0: almost dead
debug2: channel 0: gc: notify user
debug2: channel 0: gc: user detached
debug2: channel 0: send close
debug2: channel 0: is dead
debug2: channel 0: garbage collecting
debug1: channel 0: free: client-session, nchannels 1
Transferred: sent 5396, received 2996 bytes, in 0.2 seconds
Bytes per second: sent 23560.2, received 13081.3
debug1: Exit status 1

So in short, I can supply -v, -vv, or -vvv to the ssh command, and get increasing levels of verbosity.
I enjoy the opportunity to supply -v (--verbose) and -q (--quiet) flags in CLIs I implement.

[moh-hassan]

Switches can be merged together:

   -tv   parsed as  -t -v

Using the following Option class

class Options
{   
	
	 [Option('v')]
	public string Verbose { get; set; }
}

The commandline:

      -vv  =parsed to=>  -v v   =result to=> options.verbose = "v"
     -vvv  =parsed  to=>  -v vv  =result to=> options.verbose = "vv"
     -v   raise error  `Option 'v' has no value.`

[x10an14]

Thanks! =)

[x10an14]

Oh wait, I was a bit hasty, sorry!

-v raise error Option 'v' has no value.

Is that a necessity? It's not possible to give the flag -v (and just -v), and therefore set verbosityLevel to 1 as opposed to a default of 0?

Edit: To clarify, I'm under the impression now that what I quoted of your answer is something decided by the framework, not just an implementation detail you suggested.

[moh-hassan]

Verbose is defined as string not bool (so it's a Scalar option not a boolean Switch ) to accept string values as described above.
Any scalar option should have a value in the commandline.

it's not possible to give the flag -v (and just -v), and therefore set verbosityLevel to 1 as opposed to a default of 0?

Do you mean:
-v1 => -v 1
-v2 => -v 2

in that case Verbose can be integer.

[x10an14]

Just to clarify (but I think we understand each other now):

"<nothing" => "verbosity level 0"
"-v" => "verbosity level 1"
"-vv" => "verbosity level 2"
"-vvv" => "verbosity level 3"

That's as easy as;

class Options
{   
	 [Option(
	 	 'v',
	 	 MetaName = "verbosity")]
	public uint Verbosity { get; set; }
}

?

[moh-hassan]

In that case, verbose will be uint : v1 or v2 or v3 and no way to map against -v or -vv or -vvv
Just, a trick, if you want to use triple vvv:

enum VerboseEnum
{
  v =1,
  vv,
  vvv
}
class Options
{   
	 [Option(
	 	 'v',
	 	 MetaName = "verbosity",
                 Default=VerboseEnum.v)]
	public VerboseEnum Verbosity { get; set; }
}

The command can be:

           -vv /-vvv /-vvvv 

That is Quad verbosity not a triple ;) :)

Edit
in case of enum, you can use both int and enum, all are valid:

    -v1   or -vv
    -v2    or -vvv
    -v3    or   -vvvv

[x10an14]

I'm still not getting it =/

Here's my code;

namespace Slackbot
{
    // Std libs
    using System;

    // External libs
    using CommandLine;

    public class Program
    {
        protected enum VerbosityEnum
        {
            v = 1,
            vv = 2,
            vvv = 3,
        }

        public static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
            Parser.Default.ParseArguments<Options>(args)
                .WithParsed<Options>( options =>
                {
                    Console.WriteLine(
                        $"Current Arguments: -v {options.Verbosity}"
                        + "\nQuick start example.");
                });
        }

        protected class Options
        {
            [Option(
                'v',
                HelpText = "Verbosity level.",
                Default=VerbosityEnum.v)]
            public uint Verbosity { get; set; }
        }
    }
}

Here's my output from testing;

-> $ dotnet run -- -vv
program.cs(22,37): warning SA1008: Opening parenthesis should not be followed by a space. [/home/x10an14/Documents/project/project.csproj]
program.cs(13,13): warning SA1300: Element 'v' should begin with an uppercase letter [/home/x10an14/Documents/project/project.csproj]
program.cs(14,13): warning SA1300: Element 'vv' should begin with an uppercase letter [/home/x10an14/Documents/project/project.csproj]
program.cs(15,13): warning SA1300: Element 'vvv' should begin with an uppercase letter [/home/x10an14/Documents/project/project.csproj]
Hello World!
slackbot 1.0.0
Copyright (C) 2019 slackbot

ERROR(S):
  Option 'v' is defined with a bad format.
  Error setting value to option 'v': Check if Option or Value attribute values are set properly for the given type.

  -v           (Default: v) Verbosity level.

  --help       Display this help screen.

  --version    Display version information.
-> $ dotnet run -- 
Hello World!
slackbot 1.0.0
Copyright (C) 2019 slackbot

ERROR(S):
  Error setting value to option 'v': Check if Option or Value attribute values are set properly for the given type.

  -v           (Default: v) Verbosity level.

  --help       Display this help screen.

  --version    Display version information.
-> $ dotnet run -- -v
Hello World!
slackbot 1.0.0
Copyright (C) 2019 slackbot

ERROR(S):
  Option 'v' has no value.
  Error setting value to option 'v': Check if Option or Value attribute values are set properly for the given type.

  -v           (Default: v) Verbosity level.

  --help       Display this help screen.

  --version    Display version information.
-> $ 

[x10an14]

Here's a reference of how Rust's Structopt¹ (based on Clap²) enables the same feature as I'm asking for

• https://github.com/rust-cli/clap-verbosity-flag

1: https://github.com/TeXitoi/structopt
2: https://github.com/clap-rs/clap

[moh-hassan]

I'm still not getting it

• You need not to use the separate doubledash --
• The option Verbosity is VerbosityEnum not uint

[Option( 'v',
	   HelpText = "Verbosity level: v or vv or vvv Or int values 1 or 2 or 3",
	   Default=VerbosityEnum.v)]
 public VerbosityEnum Verbosity { get; set; }

• Commandline Arguments can be:

      -vv        //its 'v v'  with VerbosityLevel: v or 1
      -vvv     //its 'v vv'  with VerbosityLevel:  vv or 2
      -vvvv    //its 'v vvv'  with VerbosityLevel:  vvv or 3
  
      //using int values
      -v1        //its 'v v'  with VerbosityLevel:  v or 1
      -v2     //its 'v vv'  with VerbosityLevel:  vv or 2
      -v3    //its 'v vvv'  with VerbosityLevel:  vvv or 3
  
       //no argument, so use default value:  v or 1	
      //-v     //Not allowed, raise error: Option 'v' has no value.
     //note: don't use the prefix doubledash -- before args
  

  Working Demo: Try it online

Edit:
clab in Rust define the argument verbose with short_name(v) and compute the number of occurrence of the command (e.g for vvv ==>occurrence =3) using a method matches.occurrences_of (v)

[nomirosa]

rename "term limit" to results limit, or else add both ngrams limit and results limit

this is also per brad's feedback

[poizan42]

This issue seems to have been fixed by #684

You need to set FlagCounter=true in the attribute and enable GetoptMode on the parser. (there seems to have been some talk about changing GetoptMode to an enum instead in the future, see #690)

	var parser = new Parser(with => 
	{                   
		with.GetoptMode = true;
	});
...
class Options
{
	[Option('v', FlagCounter = true, HelpText = "Verbosity level: v or vv, vvv or vvvv")]
	public int Verbosity { get; set; }
}

Online demo: https://dotnetfiddle.net/E8Q3sL