Are ruby command line switches -rubygems & -r incompatible?

Question

I recently converted a ruby library to a gem, which seemed to break the command line usability

Worked fine as a library

  $ ruby -r foobar -e 'p FooBar.question' # => "answer"

And as a gem, irb knows how to require a gem from command-line switches

  $ irb -rubygems -r foobar
  irb(main):001:0> FooBar.question # => "answer"

But the same fails for ruby itself:

  $ ruby -rubygems -r foobar -e 'p FooBar.question'
  ruby: no such file to load -- foobar (LoadError)

must I now do this, which seems ugly:

  ruby -rubygems -e 'require "foobar"; p FooBar.question' # => "answer"

Or is there a way to make the 2 switches work?

Note: I know the gem could add a bin/program for every useful method but I don't like to pollute the command line namespace unnecessarily

Answer 1

-rubygems is actually the same as -r ubygems.

It doesn't mess with your search path, as far as I understand, but I think it doesn't add anything to your -r search path either. I was able to do something like this:

ruby -rubygems -r /usr/lib/ruby/gems/myhelpfulclass-0.0.1/lib/MyHelpfulClass -e "puts MyHelpfulClass"

MyHelpfulClass.rb exists in the lib directory specified above.

That kind of sucks, but it at least demonstrates that you can have multiple -r equire directives.

As a slightly less ugly workaround, you can add additional items to the ruby library search path (colon delimited in *nix, semicolon delimited in windows).

export RUBYLIB=/usr/lib/ruby/gems/1.8/gems/myhelpfulclass-0.0.1/lib
ruby -rubygems -r MyHelpfulClass -e "puts MyHelpfulClass"

If you don't want to mess with the environment variable, you can add something to the load path yourself:

ruby -I /usr/lib/ruby/gems/1.8/gems/myhelpfulclass-0.0.1/lib \
   -rubygems -r MyHelpfulClass -e "puts MyHelpfulClass"

Answer 2

Note: this problem exists for ruby 1.8, but is resolved in ruby 1.9.

On 1.8, if you specify both libs via -r, ruby will try to load each library without paying attention to changes in the $LOAD_PATH. But rubygems does change $LOAD_PATH so the gems can be found.

The reason it works with irb is that irb does pay attention to $LOAD_PATH changes.

Unfortunately, the best workaround I've found is to use the more verbose form:

ruby -rubygems -e 'require "foobar"; p FooBar.question'

The pain doesn't increase linearly with the number of libs though, if you use an iterator:

ruby -rubygems -e '%w(rake rspec).each{|r| require r }'