Cavalier is a command line interface generator for Go applications. Cavalier is not a library like those other CLI packages. It is an application that generates your command line parsing code for you.

Given a list of exported functions, it will create a git-like CLI with subcommands, using the function names as the subcommands, the function arguments as the flags and parameters, and the comments as the command's help docs.

For example:

// in github.com/natefinch/cavalier

// Parse parses the exported functions in target and generates a CLI. func Parse( target string, // a go file or a directory containing a go package plan9style bool, // use plan 9 style flag [use unix style] mainFunc *string, // name of "main" function [default: Main] ) error {}

Creates a command line that looks like:

$ cavalier help

Commands: Parse

$ cavalier help parse Parses the exported functions in target and generates a CLI. Target is either a go file or a directory containing a go package. usage: cavalier parse [options]

options: --plan9style use plan 9 style flag (use unix style) --mainFunc=string name of "main" function

By default, Cavalier inspects all files in the main package of your application and treats each exported function as a subcommand. A function called Main is assumed to be the default target for commands that do not have a subcommand.

This behavior can be modified in several ways at generation time:

• Instead of package main, you can specify another package (generally in a subdirectory) that contains the methods that should be used for your CLI. This is a good practice, because it means your application's logic can be reused by others as if it is a library.

• Instead of a whole package, you can specify a specific file that contains the functions for which you wish to generate a CLI. In this way, you can use only part of a package as your CLI.

• The name of the "Main" function is configurable.

• The flag behavior can be toggled between the std lib's plan9 style and unix style (i.e. if -xvf is the same as -x -v -f or --xvf).

Large quantities of flags can be hidden away as fields in a struct parameter, which can be freely combined with non-struct parameters.