.NET Command Line Parser

This project is about providing an awesome command line parser for .NET.

Goals:

• Lightweight
• Very little configuration needed
• Help strings
• Support for multiple commands, like version control tools
• Designed for cross-platform usage

Syntax

The syntax conventions are heavily inspired by the following existing conventions:

• Unix History
• POSIX Conventions
• GNU Standards for Command Line Interfaces
• GNU List of standard option names

Single Letter Qualifiers

Single character qualifiers are delimited by a single dash, e.g.

.\tool.exe -x -d -f

They can be bundled together, such as

.\tool.exe -xdf

You can also use a slash, e.g.

.\tool.exe /x /d /f

However, slashes don't support bundling. For example, the following isn't recognized:

# This is not equivalent to -xdf
.\tool.exe /xdf

Long-named Qualifiers

Long-named qualifies, also known as keyword options, are delimited by two dashes, such as:

.\tool.exe --verbose

Alternatively, you can use a slash:

.\tool.exe /verbose

Using two dashes avoids any ambiguity with bundled forms -- which is why slashes don't support bundling.

Qualifier Arguments

Both, the single letter form, as well as the long forms, support arguments. Arguments must be separated by either a space, an equal sign or a colon:

# All three forms are identical:
.\tool.exe /out result.exe
.\tool.exe /out=result.exe
.\tool.exe /out:result.exe

Multiple spaces are allowed as well:

.\tool.exe /out  result.exe
.\tool.exe /out =   result.exe
.\tool.exe /out : result.exe

Parameters

Parameters, sometimes also called non-option arguments, can be anywhere in the input:

# Both forms equivalent:
.\tool.exe input1.ext input2.ext -o result.ext
.\tool.exe input1.ext -o result.ext input2.ext

Commands

Very often, command line tools have multiple commands which have independent syntaxes. Good example are version control tools, e.g.

.\tool.exe pull origin --all
.\tool.exe commit -m 'Message'

Work in Progress

Missing

• Qualifiers must currently be unique across all commands. That's not desired. We want them to be unique only across the global and the current command.
• Add ellipses when printing multi value qualifiers and parameters
• Add argument for non-boolean qualifiers
• Make -? and --help an intrinsic and remove it from the list
• Support undocumented switches
• Consider supporting a case insensitive mode

Code

• Extract help generation from CommandLineSyntax
• Review argument checks
• Add tests
• Add comments & documentation