Emacs Ruby-Mode Indentation Behavior

Emacs 24 ruby-mode indentation behavior when using iterator such as `each`

Seems to me you're using emacs-snapshot. By default it uses a new indentation engine that's a bit buggy right now. To revert to the old one evaluate the following Emacs Lisp code:

(setq ruby-use-smie nil)

And restart ruby-mode afterwards. I'll report the bug upstream.

Emacs ruby mode if expressions indentation

I guess you actually meant to say that Emacs aligns the if with the end, which is actually pretty idiomatic in Ruby (and the style enforced by tools like RuboCop). The second indentation style is popular for method class with blocks, but not for expressions like if/unless/case.

Currently there is now way to change this behaviour. There are plans to introduce a more flexible indentation scheme in ruby-mode in the future, but that's not going to happen in the next Emacs release.

At any rate - it's not a bug, it's a feature :-)

Emacs ruby-mode, indenting wildly inside parentheses?

http://compgroups.net/comp.emacs/Ruby-mode-indentation-of-continuation-lines

(setq ruby-deep-indent-paren nil)

Or temporarily, within the current session:

M-x set-variable RET ruby-deep-indent-paren RET nil RET

Inside of a parentheses it will now indent like it does everywhere else. There is still a minor bug in the case of what I posted above. It indents 2 spaces further than I want it to, because I'm confusing it with the combination of ( and {.

Emacs ruby-mode indent private

Private doesn't introduce a new scope, so indenting definitions under it is not technically correct. While there are several indentation styles for private/protected members, the only one supported by ruby-mode is the one that is semantically correct (doesn't introduce additional nesting). The "Ruby style guide" also recommends that style (not to mention a two 2 space indentation).

That all being said - there's no way to customize this aspect of ruby-mode.

change emacs ruby-mode indent to 4 spaces

The tab-width setting only controls the width of a tab character, i.e. how many spaces a tab character is equivalent to when displayed in your buffer. It does not affect the number of spaces (or tabs) used for indenting your code.

For Ruby code, the indentation is controlled by the ruby-indent-level variable:

(setq ruby-indent-level 4)

Emacs ruby-mode: (not so) strange indentation for new Rails code conventions

This seems fixed in ruby HEAD

Can RuboCop output the proper indent level for each line?

I'm one of RuboCop's developers and an Emacs user/contributor as well. While RuboCop can't show you the correct indentation levels, so you can feed it to ruby-mode (for instance), upgrading to the unreleased Emacs 24.4 will probably solve your problems. There were a ton of ruby-mode indentation (and many other) bugs in Emacs 24.3 that were fixed in 24.4. All Ruby developers that use Emacs will do themselves a huge favour by updating their Emacs.

Indent with tab instead of spaces in Emacs ruby-mode

Try adding the following to your init.el (below the customizations you already have):

(setq-default indent-tabs-mode t)

From the documentation for indent-tabs-mode:

Indentation can insert tabs if this is non-nil.

I don't use ruby-mode so I don't know about possible interactions between indent-tabs-mode and ruby-indent-tabs-mode. It might just be enough to set indent-tabs-mode to t (and erase the customizations you made to ruby-indent-tabs-mode). But when you add the snippet above to your configuration, the default behavior for Emacs will be to insert tabs for indentation.

EDIT

As can be seen here, enh-ruby-mode defines a customizable variable called enh-ruby-indent-tabs-mode with a default value of nil. Later on the value of this variable is used to override the value of indent-tabs-mode, which is why setting indent-tabs-mode to t has no effect on buffers with enh-ruby-mode enabled.

So unless you enable any other modes besides ruby-mode and enh-ruby-mode that might be modifying the indent-tabs-mode variable, adding

(setq enh-ruby-indent-tabs-mode t)

to your init.el should fix your problem.

Another EDIT (working solution)

(Credits: This answer put me on the right track.)

Using

Emacs 24.3.1
ruby-mode version 1.2 (built-in)
enh-ruby-mode version 20140406.252 (installed via M-x package-install ...)

I was able to make it work by adding the following to an otherwise completely empty init.el file:

(package-initialize)

(setq-default tab-width 2)
(setq enh-ruby-indent-tabs-mode t)
(defvaralias 'enh-ruby-indent-level 'tab-width)
(defvaralias 'enh-ruby-hanging-indent-level 'tab-width)

This solution works for both the GUI and the console version of Emacs. It will probably integrate fine with your other customizations but you will need to remove the custom-set-variables section and everything below it from the version of your init.el you posted above.

Note also that if you do come across a situation in which Emacs inserts a space instead of a tab you can always delete it and force insertion of a tab by quoting it via C-q TAB.

Wrapping up

Turns out there is a bug in enh-ruby-mode which causes indentation to fail for blocks starting from the second level when enh-ruby-indent-tabs-mode is set to t. The author/maintainer of enh-ruby-mode has no plans of fixing it, but the bug report includes a patch that supposedly fixes the issue.