indent ruby code on the fly in emacs

Question

How to make Emacs automatically reindent Ruby code on the fly?

for example, with this in Emacs,

def hello
  puts "hello"
  en

After I type 'd', I want it to turn into this,

def hello
  puts "hello"
end

This is the default in Vim, but how can I achieve that in Emacs?

Answer 1

ruby-electric is old news. Emacs 24 has a built-in minor mode called electric-indent-mode that automatically inserts newlines after some chars and you can of course remap the RETURN key to newline-and-indent (it's mapped only to indent by default). In Emacs 24 you can get matching delims with electric-pairs-mode and ruby-end mode will insert automatically end for you when needed. You can have a look at the prelude-ruby.el for more details.

Answer 2

If you add ruby-electric (also part of Rinari) you get the following:

• Correctly indented "end" when you write "class", "def", "module" etc.
• Matching delimiters when you type the opening one.

If you don't want to add extra modes, the end will be indented correctly once you press Enter. Or you press Tab to re-indent the current line.