Hello,

Attached is a small patch that will make prettify-symbols-mode work in 
ruby-mode.  It just adapts the code that's there for perl-mode, using some of 
the symbols from python-mode.

This is my first time submitting a patch, and I hope it and this commit message 
are close to what's needed:

# -----

Make prettify-symbols-mode work with ruby-mode

* lisp/progmodes/ruby.el
   (ruby--prettify-symbols-alist): New defvar with default symbols
   to prettify; prettify-symbols-alist is then set to this

# ------

My papers are signed and on file.

Thanks,

William Denton

--
William Denton
https://www.miskatonic.org/
Librarian, artist and licensed private investigator.