Compiling / building ruby online from a working rails application

I'm totally new to Ruby but not to programming. All I did was going through try ruby and reading differences from other few languages I know better (mostly PHP and some Python). So I have no idea how Rails differ from Ruby and maybe this is an absurd question.

Anyways...

1. I don't want (or am able) to install Ruby on my machine and I'd still like to build a single working source file. Is it possible to have an online compiler of some sort? If so, how?
2. If I write a Rails web site (comprised of either one or many files) using any given host (that far I know I can), would I be able to use that same code with very minor modifications and just run as a Ruby app? Again, how?
3. (new) What about the other way around: a Ruby app turning into a Rails w开发者_JS百科eb page? Easy to do?

I really hope for a "yes" on them all, but I doubt on the 1st and not so much on the last. :)

1. There are online "IDEs" you can use to try out ruby:

   • http://ideone.com
   • http://codepad.org
     
     

   But mind you that Ruby on Rails is a framework written in Ruby and those sites don't have RoR installed. Also note you that a Rails app has many, many files.

2. If you have the same code and same server configuration (version of ruby, database, plugins, etc.) you should only need minor modifications to the config file.

3. Ruby on Rails is on Ruby. So whatever works on Ruby should work just fine on RoR with minor modifications. However, you'll probably want to rewrite the app to take advantage of many of the features RoR provides.