CommandLine.NetCore 1.0.0

CommandLine.NetCore

CommandLine.NetCore library provides support to handle command line arguments (parse, validate, command pattern) for .Net Core console applications with ANSI VT support (cursor,colors,screen size) for multi-plateform (windows, linux, osx, arm) console applications using C# and .NET Core 6

This project is licensed under the terms of the MIT license: LICENSE.md

Features

The library provides functionalities needed to build console applications running in a terminal (WSL/WSL2, cmd.exe, ConEmu, bash, ...) with text interface. That includes:

• parsing command line arguments

• command pattern helps implementing commands binded to mthods from command line in a simple and regular way

• multi-language commands help configuration files

• automatic help command

• compatibile with AnsiVtConsole.NetCore :

  • a text printer engine that supports print directives allowing to manage console functionalities from text itself, as html would do but with a simplest syntax (that can be configured). That makes possible colored outputs, cursor control, text scrolling and also dynamic C# execution (scripting), based on System.Console and ANSI VT100 / VT52 (VT100 type Fp or 3Fp, Fs, CSI, SGR)

  • The console output can be controlled by:

    • tokens in a string (print directives)
    • as string shortcuts (dynamic ansi vt strings)
    • throught API methods

Howto

1. Running the command line

download the nuget from command line or add it from Visual Studio

@rem version 1.0.0 or any new one
dotnet add package CommandLine.NetCore --version 1.0.0

link to the library in your console application main class (example: Program.cs):

using CommandLine.NetCore;

from your main method, transfer control to the library CommandLine.NetCore :

/// <summary>
/// command line input
/// <para>commandName (commandArgs|globalArg)*</para>
/// </summary>
/// <param name="args">arguments</param>
/// <returns>status code</returns>
public static int Main(string[] args)
    => new CommandLineInterfaceBuilder()
        .Build(args)
        .Run();

That leads to the loading of any command line components like global arguments, commands and help settings from both the library core and your own console app.

2. Testing the integrated help command:

Any console application built with the library ComandLine.NetCore implements by default a command named help that dump any available help about commands that are implemented in the software that uses the library and in the library itself.

As an example, you can build the example application console, provided in the project CommandLine.NetCore.Example, Just execute in your favorite shell this command (available in the folder bin/Release/net6.0):

./CommandLine.NetCore.Example.exe help

To get the help for a particular command, the syntax is help {commandName}. In this example you get help about the command help:

./CommandLine.NetCore.Example.exe help help

3. Configuring the library and a console application built with it

The library settings provides the description of the application and of the commands, and also the translation of texts. You should override these settings according to your needs.

Every settings are pushed throught IHostBuilder.ConfigureAppConfiguration. Settings are looked up by this way, in the specified order:

provided by the library CommandLine.NetCore:

• appSettings.core.json : this file contains the settings needed by the core functionalities of the library: decription of the library, texts and description of the integrated command, in the default language (en-us)

• appSettings.core.{culture}.json : same as above, any of these files provides translations for the culture specified by the tag {culture} according to available cultures specified in Microsoft.. The settings file that matches the current platform culture is loaded if it exists.

provided by your application;

• appSettings.json : dscription of the commands provided by your application, the texts, and any settings in the default language (en-us)

• appSettings.{culture}.json : same as above for the translations of the culture specified by the tag {culture}

The settings must conform with the following conventions:

Informations about application

"App": {
    "Title": "CommandLine.NetCore",
    "ReleaseDate": "10/12/2022"
  }

Texts

"Texts": {
    "{TextId}": "Text"
  }

Description of the commands

"Commands": {
    "{CommandName}": {
        "Description": "short description of the command",
        "Syntax": {
            "{Syntax 1}" : "Description of the functionality provided by the syntax 1",
            ...
            "{Syntax n}" : "Description of the functionality provided by the syntax n",
        },
        "Options": {
            "{Option 1}" : "Description of the command option 1",
            ...
            "{Option n}" : "Description of the command option n",
        }
    }
  }

example of the command help :

"Commands": {
    "help": {
      "Description": "output a of list commands and global arguments or output help about a command",
      "Syntax": {
        "": "list all commands",
        "commandName": "help about the command with name commandName"
      },
      "Options": {
        "-v": "enable verbose: add details to normal output",
        "--info" : "output additional informations about the command line context"
      }
    }
  },

These settings are describing the following syntaxes for the command help:

; help for a command
help {commandName} [-v] [--info]
; global help (all commands)
help [-v] [--info]

Command options are optionals and are available for any syntax of the command (here -v and --info). They can appears from the position they are declared in the command syntax

Description of the global arguments

"GlobalOptions": {
    "{ArgumentName}": {
        "{Syntax}" : "Description of the functionality provided by the argument syntax"
    }
  }

Global arguments are optional and available for any command. They must appears from the end of the command arguments

example of the global argument s :

"GlobalOptions": {
    "s": {
        "-s" : "turn off any output (silent mode)"
    }
  }

by convention (POSIX), single letter arguments are prefixed by -, whereas arguments with several letters are prefixed by --

4. Implementing a command

A command specification and implementation is definied in a class that inherits from CommandLine.NetCore.Services.CmdLine.Commands.Command.

• the name of the command is kebab case from the name of the class (in this case GetInfo declares the get-info command)
• the command class msut have a constructor with parameter Dependencies. These classes are instantiated by the dependency injector, thus any registered dependency can be added as a constructor parameter
• the command class must implements the method:

  CommandResult Execute(ArgSet args)
  

• the method Execute declares the syntaxes of the command and the related implementations
• the method For declares a command syntax:

  For(params Arg[] syntax)
  

• the list of arguments are specifing the command syntax
  • an Arg is either an option or a parameter. Their grammar is defined as this:

    • Option ::= [-|--]{optionName}[value0..valuen]

      • options can be expected or optionnal
      • can have from 0 to n values of a type T, where T can be any scalar type, a collection of scalar types (with , as separator) or an Enum
      • an option can be defined with values, values are always expected
      • Opt("x") builds the option x with no expected value: -x
      • by convention (posix), if the length of the name of the option is greater than 1, the prefix becomes: --. For instance, Opt("xy") defines the syntax: --xy
      • Opt("x",true) builds the option x wich is optional in the syntax
      • Opt<T>("value") builds the option value having one expected value that must be convertible to type T. For instance, Opt<int>("value") defines an option that expect an int, like in syntax: --value 123

    • Parameter ::= parameterValue?

      • parameters are always expected
      • have a value of a type T, where T can be any scalar type, a collection of scalar types (with , as separator) or an Enum
      • if a parameter if defined with a value, it is an expected word in the syntax
      • if a parameter is defined without a value, a value is expected in the syntax
      • Param() builds a parameter that expect a value of type string like in syntax: iamastring
      • Param<T>() builds a parameter that expect a value that must be convertible to type T. For instance, Param<int>() builds a parameter that expect a value of type int, like in syntax: 123
      • Param("color") builds a parameter that is expected and being the syntax: color

• the method Do chained to a For indicates the method that must be executed if the syntax match the command line args:

  // with no parameter and void result delegate
  Do(Action @delegate)
  // with no parameter and void result delegate
  Do(Func<OperationResult> @delegate)
  // with parameter operation context and void delegate
  Do(Action<OperationContext> @delegate)
  // with parameter operation context and OperationResult result delegate
  Do(Func<OperationContext, OperationResult> @delegate)
  // takes a method in a lambda unary call expression: () => methodName, takes a called method with no parameter, takes a called method with a default command result (code ok, result null).
  // Allows to map command arguments to method parameters and operation context
  Do(LambdaExpression expression)
  

• methods For can be chained
• the method Options can be chained to a For. This method allows to declares the command options:

  Options(params IOpt[] options)
  

• the method With launch the command executing process. First command line parsing, then syntax matching, then operation dispatch:

  With(ArgSet args)
  

Exemple of the command help defined in CommandLine.NetCore.Commands.CmdLine:

// command syntax: help [commandName] [-v] [--info]
internal sealed class Help : Command
{
    protected override CommandResult Execute(ArgSet args) =>

        // syntax: help
        For()
            .Do(() => DumpHelpForAllCommands)

        // syntax: help {commandName}
        .For(Param())
            .Do(() => DumpCommandHelp)

        // any syntax accepts -v and/or --info
        .Options(Opt("v"), Opt("info"))

        // parse and run
        .With(args);

    
    private void DumpCommandHelp(Param commandName, Opt v, Opt info)
    {
        // ...
    }

    private void DumpHelpForAllCommands(Opt v, Opt info)
    {
        // ...
    }
}

Exemple of the command get-info defined in CommandLine.NetCore.Example.Commands.GetInfo:

// syntax: get-info (env -l) | (env {varName}) | console | system | --all
internal sealed class GetInfo : Command
{
    protected override CommandResult Execute(ArgSet args) =>

        // syntax: get-info env -l
        For(
            Param("env"),
            Opt("l")
            )
                .Do(DumpAllVars)

        // syntax: get-info env {varName}
        .For(
            Param("env"),
            Param())
                .Do(() => DumpEnvVar)

        // syntax: get-info console
        .For(
            Param("console"))
                .Do(DumpConsole)

        // syntax: get-info system
        .For(
            Param("system"))
                .Do(DumpSystem)

        // syntax: get-info --all
        .For(
            Opt("all"))
                .Do(DumpAll)

        // parse and run
        .With(args);

    private void DumpEnvVar(Param envVarName)
    {
        // ...
    }
}

Version history

1.0.0 init