Use bash globbing to set RUBIES

[ktchen14]

This is an alternative to #406. It fixes #413 and uses bash native functionality instead of ls at all. The impetus for this change is that an alias to ls breaks chruby. Specifically in my case I have:

alias ls=exa

Which doesn't have a -A flag.

[havenwood]

A shell-based solution would need to be portable to zsh since chruby support bash and zsh.

For the moment, you can source chruby before you set your exa alias for a fix.

[havenwood]

This would need to either be implemented portably for bash/zsh or you could do a if statement with a bash- and zsh-specific version.

Adding proper ordering would be a real win.

[havenwood]

In zsh, the shopt equivalent would be setopt.

[havenwood]

Another thing to consider is the sort order. In zsh, you can get a proper numeric sort fairly easily, so 2.10 is greater than 2.9.

Here is a zsh one-liner.

echo "${(@n)RUBIES}"

Or to print each Ruby in order:

printf "%s\n" "${(@n)RUBIES:t}"

[havenwood]

See #278 for a stab at numeric sorting. We discussed the possibility of creating a shell library for portable numeric sorting, since it's an annoying gap. I'm for switching to a portable shell solution but think it should fix the numeric sorting issue too.

[ktchen14]

@havenwood I just pushed a new version of the code which should be zsh compatible. I don't really use zsh but from a careful reading of the documentation this is the simplest version that I think works for both bash and zsh.

[ktchen14]

Also this doesn't handle ordering. That looks hard to do in a portable fashion and I believe is out of scope for this PR.

[ktchen14]

Ping. Please let me know if there are any changes I should make or if I should close this PR. Thanks!