IJKL shortcuts plugin

This plugin adds alt-ijkl navigation shortcuts to the current keymap, tool windows, and popups. The idea is that these shortcuts are more ergonomic for navigation/editing than using keyboard arrows, so you can stop using arrows in the IDE editor.

These shortcuts are inspired by Vim and gaming keyboard layouts.

You can see the shortcuts in action in this talk.

Shortcuts

Editor navigation:

• alt-i - line up
• alt-j - move to previous word
• alt-k - line down
• alt-l - move to next word
• alt-n - move left
• alt-m - move right
• alt-u - move to line start
• alt-o - move to line end
• alt-f - page down
• alt-w - page up
• alt-shift-ijklmnuo - move with selection

Editor text modification:

• alt-e / alt-shift-e - expand/shrink word selection
• alt-; - delete next character
• alt-d - delete next word
• alt-y - remove line
• alt-ctrl-shift-ik - move statement up/down
• alt-ctrl-shift-jl - move element left/right
• alt-cmd-shift-ik (macOS) - move statement up/down
• alt-cmd-shift-jl (macOS) - move element left/right
• alt-/ - cyclic expand word (aka hippie completion)
• alt-' - code completion
• cmd-l or ctrl-l - complete statement

Search and navigation between files:

• alt-a - highlight usages in file
• alt-s - show usages popup
• alt-shift-s - find usages
• alt-h - go to declaration or usages
• ctrl-cmd-b or ctrl-alt-b - implementations popup
• alt-b - back
• alt-shift-b - forward

Tab navigation:

• cmd-shift-[ - previous tab
• cmd-shift-] - next tab
• alt-q - close tab
• ctrl-shift-t - reopen closed tab

Why editor navigation shortcuts?

Because existing key layouts are inefficient and painful to use. See the reasons for choosing particular keys below.

IJKL

When touch typing you would normally position your index fingers on letters f and j. This is fine for writing a lot of text sequentially. The problem is that writing/editing code is never linear and requires a lot of navigation even for simplest tasks. Navigation with standard key layouts makes you move right hand from j letter to arrows and back to j. This takes a lot of effort.

It would be great move the arrow eys into the area with letters. This is what ijkl mapped to up/left/down/right is trying to achieve.

Alt

There are several options how to make ijkl work for navigation.

One option could be something like Vim command/insert modes, i.e. "command mode" in which ijkl keys work as arrows and "insert mode" in which all keys work as in traditional editors.

Another option is to use modifier keys to change behaviour of ijkl letters (or you might think about it as enabling "command mode" only when modifier key is pressed). In general, this option is easier to implement in various editors/IDEs. And among modifier keys, alt (the left one) was the least used in existing IDE keymaps.

MN and move to next/previous word

Three is a problem with arrow navigation that left/right arrows jump only one character at a time. You can use ctrl-left/right (or alt-left/right on macOS) to jump between words. This is more useful and, arguably, should be the default navigation for arrows. That's why in alt-jl moves caret to previous/next word. Single character navigation is still useful sometimes, so it's mapped to alt-nm. There is no particular reason for these letters except that they are located not too far from ijkl.

UO

Moving to the start/end of line is another important part of navigation, so ideally it should be mapped to keys not far from ijkl. For this reason u and o seem like a great choice.

Moving to the start of line is u because it is close to j and essentially also means moving caret left. And o is mapped to the end of line because it's about moving right, similar to l (there is an implicit assumption here that you're writing code left to right).

FW

The choice of fw letters mapped to page down/up was copied from less and admittedly is somewhat arbitrary.

MacOS Caveats

There are few issues when using alt-ijkl shortcuts with built-in macOS keyboard layouts:

1. dead keys cannot be used as IDE shortcuts (e.g. alt-i in US layout)
2. if alt-ik are mapped to some character, then Navigate to Class action handles alt-ik shortcuts as both navigation up/down and entering a character.
3. keys with certain output, when held down, trigger IDE action only once (e.g. alt-i with 'ˆ' output in US layout).

The first two issues can be solved by adding keyboard input source which doesn't have dead keys and doesn't output characters for alt-ijkl shortcuts. See section below.

To solve the third issue you can disable sticky keys feature by executing in shell defaults write -g ApplePressAndHoldEnabled -bool false.

How to install macOS input source

On IDE startup the plugin will suggest to add keyboard input sources. In practice, this means that plugin will create ~/Library/Keyboard Layouts/ijkl-keys.bundle directory with a bunch of files.

After input sources were installed, open macOS System Preferences -> Keyboard -> Input Sources and click on + to add input sources.

Choose U.S. - IJKL or British - IJKL input source from English category and click Add button. (If you don't see these inputs, you might need to log out / log in or restart.)

Now you can switch to the new input source in IDE and use alt-ijkl shortcuts.

How to hide "default" input source

If you're happy with custom layout and want to hide built-in layout from input source list, follow these steps:

• change the current input source to your custom keyboard layout
• open ~/Library/Preferences/com.apple.HIToolbox.plist (requires XCode)
• remove the input source or input sources you want to disable from the AppleEnabledInputSources dictionary; if there is an AppleDefaultAsciiInputSource key, remove it
• restart