ArgsNET

A .NET command line argument parser. It can be used without any configuration, as long as you have a class that can receive the data. For example:

var arguments = ArgsNET.Deserialize.SystemArguments().To<Arguments>(out var errors);

This assumes we have a class along the lines of this:

class Arguments
{
    public bool help;
    public string[] input;
    public string output;
}

The above would be able to parse any of the following automatically:

Variable	CLI arguments	Accepts value
Arguments.help	-h / --help	No
Arguments.input	-i / --input	Yes, like -i index.html index.js index.css
Arguments.output	-o / --output	Yes, like -o build/index.html

Detailed information

Flags

All booleans are understood as flags. A flag does not accept a value, and is instead called just with the argument, like -v or --help. When this happens, the relevant boolean field or property will be set to true.

Note that flags may only be set once, multiple arguments of the same flag, like -h -h, will cause a parse error to be returned, marking the second instance as incorrect.

Options

All non-booleans are understood as options. These may accept one or multiple values, depending on if they are arrays (any other collection), or if they are a regular value like just a string or int. The regular values may only be set once, just like flags. Arrays and lists, however, may be set as many times as desired. This can be done with any of the following methods:

Multi-value method	Example
Space separated	-i value1 value2 value3
Comma separated	-i=value1,value2,value3
Multiple arguments	-i value1 -i value2 -i value3

Argument names

If nothing else is specified the argument names are resolved by using the field or property name into a long and short version. The long names are resolved first, and will be formatted as this:

Variable name	Argument name
example	--example
FieldExample	--field-example
PropertyExample	--property-example
nameWith123Numbers	--name-with-123-numbers

The short name, meanwhile, is resolved by using the long name above and trimming it to only use the first letter of each section, like this:

Long name	Short name
--example	-e
--really-verbose-name	-rvn
--name-with-123-numbers	-nw1n

Custom argument names

It is possible to define custom names, instead of using the automatic name resolver by using the ArgumentName attribute:

[ArgumentName("o", "output")]
public string output;

[ArgumentName("r", "hot-reload")]
public bool hotReload;

Note that we do not add any hyphens at the start of the name. Those will be added automatically.

It is also possible to only set the long argument, and have the short one be automatically generated:

[ArgumentName("output")] // Short = "-o"
public string output;

[ArgumentName("hot-reload")] // Short = "-hr"
public bool hotReload;

Deserializer options

There are three ways to deserialize arguments:

Method	Example	Description
SystemArguments	Deserialize.SystemArguments()	Uses the arguments given to the application
String	Deserialize.String("-o example.txt")	Uses a raw string
Arguments	Deserialize.Arguments(someArgs)	Uses a string array

In most cases the regular SystemArguments method will suffice, but in some cases you have different handling depending on the first argument, like npm install or git switch, where the first argument is not a flag. In these cases it's recommended to implement a switch on the first argument, and then use the Arguments method with the something like Deserialize.Arguments(args.Skip(1).ToArray()).