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Executable
Executable is to the commandline, what ActiveRecord is the database. You can think of Executable as a COM, a Command-line Object Mapper, just as ActiveRecord is an ORM (Object Relational Mapper). Any class mixing in Executable or subclassing Executable::Command can define a complete command line tool using nothing more than Ruby's standard syntax. No special DSL is required.
Features
- Easy to use, just mixin or subclass.
- Define #call to control the command procedure.
- Public writers become options.
- Namespace children become subcommands.
- Or easily dispatch subcommands to public methods.
- Generate help in plain text or markdown.
Limitations
- Ruby 1.9+ only.
- Help doesn't handle aliases well (yet).
Overview
CLIs can be built by using a Executable as a mixin, or by subclassing
Executable::Command
. Methods seemlessly handle command-line options.
Writer methods (those ending in '=') correspond to options and query
methods (those ending in '?') modify them to be boolean switches.
For example, here is a simple "Hello, World!" commandline tool.
require 'executable'
class HelloCommand
include Executable
# Say it in uppercase?
def loud=(bool)
@loud = bool
end
#
def loud?
@loud
end
# Show this message.
def help!
cli.show_help
exit
end
alias :h! :help!
# Say hello.
def call(name)
name = name || 'World'
str = "Hello, #{name}!"
str = str.upcase if loud?
puts str
end
end
To make the command available on the command line, add an executable to your project calling the #execute or #run methods.
#!usr/bin/env ruby
require 'hello.rb'
HelloCommand.run
If we named this file hello
, set its execute flag and made it available
on our systems $PATH, then:
$ hello
Hello, World!
$ hello John
Hello, John!
$ hello --loud John
HELLO, JOHN!
Executable can also generate help text for commands.
$ hello --help
USAGE: hello [options]
Say hello.
--loud Say it in uppercase?
--help Show this message
If you look back at the class definition you can see it's pulling
comments from the source to provide descriptions. It pulls the
description for the command itself from the #call
method.
Basic help like this is fine for personal tools, but for public facing
production applications it is desirable to utilize manpages. To this end,
Executable provides Markdown formatted help as well. We can access this,
for example, via HelloCommand.help.markdown
. The idea with this is that
we can save the output to man/hello.ronn
or copy it the top of our bin/
file, edit it to perfection and then use tools such a ronn,
binman or md2man
to generate the manpages. What's particularly cool about Executable,
is that once we have a manpage in the standard man/
location in our project,
the #show_help
method will use it instead of the plain text.
For a more detailed example see QED, API documentation and, in particular, the Wiki.
Installation
Install with RubyGems in the usual fashion.
$ gem install executable
Contributing
Executable is a Rubyworks project. As such it largely uses in-house tools for development.
Submitting Patches
If it is a very small change, just pasting it to an issue is fine. For anything more than this please send us a traditional patch, but even better use Github pull requests. Good contributions have the following:
- Well documented code following the conventions of the project.
- Clearly written tests with good test coverage written using the project's chosen test framework.
- Use of a git topic branch to keep the change set well isolated.
The more of these bullet points a pull request covers, the more likely and quickly it will be accepted and merged.
Testing
QED and Microtest
are used for this project. To run the QED demos just run the qed
command, probably with bundler,
so bundle exec qed
. And to run the microtests you can use rubytest test/
, again with bundler,
bundle exec rubytest test/
.
Getting In Touch
For direct dialog we have an IRC channel, #rubyworks on freenode. But it's not always manned, so a mailing list is also available. Of course these days, the GitHub issues page is generally the place get in touch for anything specific to this project.
Copyrights
Executable is copyrighted open source software.
Copyright (c) 2008 Rubyworks (BSD-2-Clause)
It can be distributed and modified in accordance with the BSD-2-Clause license.
See LICENSE.txt for details.