Ruby 1.9/1.8 compatibility: String#lines

It seems the most important change in 1.9, in terms of compatibility, is
that String isn't Enumerable anymore. It breaks a lot of scripts on my
system.

I couldn't find an easy way to make scripts running under both 1.8 and 1.9:

- String#each_line requires a block in 1.8, and writing each_line{}
  isn't really beautiful.
- String#to_a isn't available in 1.9.
- The "dirty fix":

    class String
      alias each lines
      include Enumerable
    rescue
    end

  is surely not what we want.

So, what is the preferable way to make scripts and libraries that use
String#each 1.9-ready? It may be okay to force developers to update
their code, but there should be an easy way not to break backward
compatibility in the process.

[murphy]