gem which cannot find gem despite it being installed - ruby

Question

I've built my first gem but I don't seem to be able to get it to install correctly. I can issue the command
sudo gem install ceilingfish-toto
Which produces the output
Successfully installed ceilingfish-toto-0.3.6
1 gem installed
But when I then type gem which ceilingfish-toto. I get the output
Can't find ruby library file or shared library ceilingfish-toto
Which is very strange because if I go and look in my gems folder I can see all the files installed there
# ls -l /opt/local/lib/ruby/gems/1.8/gems/ceilingfish-toto-0.3.6/
total 48
-rw-r--r-- 1 root admin 1053 14 Feb 17:16 LICENSE
-rw-r--r-- 1 root admin 6166 14 Feb 17:16 README.md
-rw-r--r-- 1 root admin 879 14 Feb 17:16 Rakefile
-rw-r--r-- 1 root admin 6 14 Feb 17:16 VERSION
-rw-r--r-- 1 root admin 2477 14 Feb 17:16 ceilingfish-toto.gemspec
drwxr-xr-x 7 root admin 238 14 Feb 17:16 test
Does anyone know what could cause this? I think it's complaining because there is a hyphen in the gem name. You can see the gemspec here http://github.com/ceilingfish/toto

Answer 1

It's not the hyphen.
gem which searches for library files in gems, not gems. Compare:
$ gem which haml
/home/dave/.gem/ruby/1.8/gems/haml-3.0.12/lib/haml.rb
$ ls haml-3.0.12/lib/h*
haml haml.rb haml.rbc
Peachy. Note the existance of lib/haml.rb.
$ gem which rails
ERROR: Can't find ruby library file or shared library rails
$ ls rails-2.3.8/lib/r*
rails_generator.rb railties_path.rb rubyprof_ext.rb ruby_version_check.rb
There is no lib/rails.rb. But try:
$ gem which railties_path # not a gem
/home/dave/.gem/ruby/1.8/gems/rails-2.3.8/lib/railties_path.rb
So gem which ceilingfish-toto throws an error even when ceilingfish-toto is installed because there is no lib/ceilingfish-toto.rb file (there's not even a lib folder).

Answer 2

gem which ceilingfish-toto looks through the gem require path for a file named ceilingfish-toto.rb. Since there isn't one, it returns nothing. What would work for you is gem which toto, but since lib/ is not included in your gem spec, the lib files are not installed, so it doesn't exist.
Rerunning rake gemspec might fix the problem.
As an aside, you can check whether a gem is installed by its name by using gem list ceilingfish-toto which should show you it is installed, regardless of the files it has(it will also list the versions installed).

Answer 3

According to the gem naming recommendations:
If you’re adding functionality to another gem, use a dash. This usually corresponds to a / in the require statement (and therefore your gem’s directory structure) and a :: in the name of your main class or module.
If this is the case, if your gem is named alpha-beta you need to add a slash (/) to the gem which command
gem which alpha/beta