Usage

The plugin defines two commands, :SidewaysLeft and :SidewaysRight, which move the item under the cursor left or right, where an "item" is defined by a delimiter. As an example:

def function(one, two, three):
    pass

Placing the cursor on "two" and executing :SidewaysLeft, the "one" and "two" arguments will switch their places, resulting in this:

def function(two, one, three):
    pass

In this case, the delimiter is a comma. The plugin currently works with various other cases and it's intended to make the process configurable. While this particular example is in python, this should work for arguments in many different languages that use round braces to denote function calls.

For ruby and eruby, it detects method calls without braces as well:

link_to user_registration_path, 'Something'
# changes to:
link_to 'Something', user_registration_path

Apart from functions, it works for square-bracket lists in dynamic languages:

list = [one, [two, four, five], three]

If you experiment with this example, you'll find that you can move the entire second list around, as long as the cursor is on one of the inner brackets. The plugin takes into consideration nested structures.

It also works for multiline lists. Try experimenting with this example:

<div class="example"
     style="color: red;"
     something="other">
  Example
</div>

It's highly recommended to map the two main commands to convenient keys. For example, mapping them to <c-h> and <c-l> would look like this:

nnoremap <c-h> :SidewaysLeft<cr>
nnoremap <c-l> :SidewaysRight<cr>

The plugin also provides the commands :SidewaysJumpLeft and :SidewaysJumpRight, which move the cursor left and right by items.

Other things that sideways works for:

CSS declarations:

a { color: #fff; background: blue; text-decoration: underline; }

Lists within CSS declarations:

border-radius: 20px 0 0 20px;

HTML attributes:

<input name="one" id="two" class="three" />

Handlebars components:

{{parent/some-component one=two three="four" five=(action 'six')}}

Cucumber tables:

Examples:
  | input_1 | input_2 | button | output |
  | 20      | 30      | add    | 50     |
  | 2       | 5       | add    | 7      |
  | 0       | 40      | add    | 40     |

Go lists:

[]string{"One", "Two", "Three"}

Javascript-like objects:

dict = {one: 1, two: 2, three: 3}

The plugin is intended to be customizable, though at this point you'd need to look at the source to do this.

Bonus functionality

The plugin's machinery makes it easy to implement an "argument" text object. There are two mappings provided:

<Plug>SidewaysArgumentTextobjA
<Plug>SidewaysArgumentTextobjI

These are the outer and inner text objects, respectively. To use them, you need to create mappings in your configuration files. Something like this:

omap aa <Plug>SidewaysArgumentTextobjA
xmap aa <Plug>SidewaysArgumentTextobjA
omap ia <Plug>SidewaysArgumentTextobjI
xmap ia <Plug>SidewaysArgumentTextobjI

This will map the "a" text object to operate on an "argument". So, you can perform daa to delete an argument, cia to change an argument, and so on. See :help text-objects for more information.

Also, a useful plugin to use alongside sideways is fieldtrip. This defines a submode for sideways.vim.