Trollop 1.11 has been released. This is a minor release with only one new feature: when an option <opt> is actually given on the commandline, a new key <opt>_given is inserted into the return hash (in addition to <opt> being set to the actual argument(s) specified).

This allows you to detect which options were actually specified on the commandline. This is necessary for situations where you want one option to override or somehow influence other options. For example, configure’s --exec-prefix and --bindir flags: if --exec-prefix is specified, you want to override the default value for --bindir, unless that’s also given. If neither are given, you want to use the default values.

This should be a backwards-compatible release, except for namespace issues, if you actually had options called <something>-given.

I released a new version of Trollop with a couple minor but cool updates.

The best part is the new :io argument type, which uses open-uri to handle filenames and URIs on the commandline. So you can do something like this:

require 'trollop'
opts = Trollop::options do
  opt :source, "Source file (or URI) to print",
      :type => :io,
      :required => true
end
opts[:source].each { |l| puts "> #{l.chomp}" }

Also, when trying to detect the terminal size, Trollop now tries to `stty size` before loading curses. This gives better results when running under screen (for some reason curses clears the terminal when initializing under screen).

I’ve also cleaned up the documentation quite a bit, expanding the examples on the main page, fixing up the RDoc comments, and generating the RDoc documentation with a modern RDoc, so that things like constants actually get documented.

If you’re still using OptParse, you should really give Trollop a try. I guarantee you’ll write much fewer lines of argument parsing code, and you’ll get all sorts of nifty features like help page terminal size detection.

Trollop 1.8.1 is out. This is a minor bugfix release, but 1.8, released a few weeks ago but not really advertised, adds new functionality, so I’m describing that here.

The new functionality is subcommand support, as seen in things like git and svn. This feature is actually trivial to use / implement: you give Trollop a list of stopwords. When it sees one, it stops parsing. The end. That’s all you need.

Here’s how you use it:

• Call Trollop::options with your global option specs. Pass it the list of subcommands as the stopwords. It will parse ARGV and stop on the subcommand.
• Parse the next word in ARGV as the subcommand, however you wish. ARGV.shift is the traditional choice.
• Call Trollop::options again with whatever command-specific options you want.

And that’s it. Simple eh?

It continually amazes me how hard other people make option parsing. I think it’s a holdover from their days of using C or Java. Take a look at synopsis for optparse — it’s a ridiculous amount of work for something simple. Or better yet, look at the synopsis for CmdParse. Having to make a class for each command is a clunky Java-ism. I’m sorry, but it’s true. Subclassing is the one option for specializing code in Java; in Ruby we can be far more sophisticated. Take a look at Ditz’s operator.rb for an example of a subcommand DSL.