im-switch.nvim

A Neovim plugin that automatically switches keyboard input method to English when Neovim is focused or in normal mode, and restores the previous input method when entering insert mode.

Perfect for users who type in multiple languages and want seamless input method switching in Neovim.

im-switch.mov

Features

• Auto-switch to English when Neovim gains focus
• Smart mode switching: English in normal/command mode, restore in insert mode
• macOS native: Uses macOS Text Input Source APIs
• Linux support: Works with IBus, Fcitx, Fcitx5, and XKB layouts
• Windows support: Controls IME status (doesn't change input methods)

Installation

Using lazy.nvim

{
  "chojs23/im-switch.nvim",
  build = "make build",
  config = function()
    require('im-switch').setup({
      -- Configuration options (see below)
    })
  end,
  event = "VeryLazy",
}

Using packer.nvim

use {
  'chojs23/im-switch.nvim',
  config = function()
    require('im-switch').setup()
  end
  run = 'make build',
}

Configuration

require('im-switch').setup({
  -- Path to the binary (auto-detected if not specified)
  binary_path = 'im-switch',

  -- Default input method ID (platform-specific defaults)
  -- macOS: 'com.apple.keylayout.ABC'
  -- Linux: 'us' (XKB), 'xkb:us::eng' (IBus), 'keyboard-us' (Fcitx)
  -- Windows: 'en-US'
  default_input = nil, -- Uses platform default

  -- Auto-switch to default input in normal mode (default: true)
  auto_switch = true,

  -- Auto-restore previous input in insert mode (default: false) (experimental)
  auto_restore = false,

  -- Enable debug logging (default: false)
  debug = false,
})

Usage

The plugin works automatically once installed. However, you can also control it manually:

Commands

  :ImSwitchEnable " Enable plugin
  :ImSwitchDisable " Disable plugin
  :ImSwitchToggle " Toggle plugin state
  :ImSwitchStatus " Show current status and input method

Lua API

local im_switch = require('im-switch')

-- Enable/Disable controls
im_switch.enable()        -- Enable the plugin
im_switch.disable()       -- Disable the plugin
local enabled = im_switch.toggle()  -- Toggle and return new state
local is_on = im_switch.is_enabled() -- Check if enabled

-- Input method controls
im_switch.switch_to_english()  -- Switch to default input
im_switch.restore_input()      -- Restore previous input method

-- Get current input method
local current = im_switch.get_current()
print(current)

-- Set specific input method
im_switch.set_input('com.apple.inputmethod.Korean.2SetKorean')

-- List all available input methods
local inputs = im_switch.list_inputs()
for _, input in ipairs(inputs) do
  print(input)
end

How It Works

The plugin automatically handles these events:

1. Focus Events: When Neovim gains focus → switches to default input
2. Mode Changes:
   • Normal/Command mode → switches to default input
   • Insert mode (from normal) → restores previous input method (if auto_restore is enabled)

Finding Input Method IDs

To discover available input method IDs on your system:

# Build the binary first
make build

# List all input methods
./build/im-switch -l

Common Input Method IDs

macOS

• com.apple.keylayout.ABC - US English
• com.apple.inputmethod.Korean.2SetKorean - Korean (2-Set)
• com.apple.inputmethod.Korean - Korean
• com.apple.inputmethod.SCIM.ITABC - Chinese (Simplified)
• com.apple.inputmethod.TCIM.Cangjie - Chinese (Traditional)

Linux

XKB Layouts (setxkbmap):

• us - US English
• gb - UK English
• de - German
• fr - French
• ru - Russian
• cn - Chinese
• jp - Japanese
• kr - Korean

IBus Engines:

• xkb:us::eng - US English
• libpinyin - Chinese Pinyin
• anthy - Japanese
• hangul - Korean

Fcitx/Fcitx5:

• keyboard-us - US English
• pinyin - Chinese Pinyin
• mozc - Japanese
• hangul - Korean

Windows

Keyboard Layout Names:

• en-US - English (United States)
• en-GB - English (United Kingdom)
• de-DE - German (Germany)
• fr-FR - French (France)
• ja-JP - Japanese
• ko-KR - Korean
• zh-CN - Chinese (Simplified)
• zh-TW - Chinese (Traditional)
• ru-RU - Russian

Layout IDs (alternative format):

• 00000409 - English (United States)
• 00000809 - English (United Kingdom)
• 00000407 - German (Germany)
• 0000040c - French (France)
• 00000411 - Japanese
• 00000412 - Korean
• 00000804 - Chinese (Simplified)
• 00000404 - Chinese (Traditional)
• 00000419 - Russian

Building Manually

If you need to build the binary manually:

# Build for development
make build

# Build optimized release version
make build-release

# Install system-wide (optional)
make install

# Run tests
make test

Troubleshooting

Binary not building automatically

• Ensure you have Go installed and CGO enabled
• Check that you have Xcode command line tools: xcode-select --install
• Try building manually: make build

Plugin not switching inputs

1. Enable debug mode to see what's happening:

   require('im-switch').setup({ debug = true })

2. Check available input methods: ./build/im-switch -l
3. Verify your default_input setting matches an available input method

Permission errors

• The plugin only reads/writes input methods, no special permissions needed
• If you see permission errors, try rebuilding: make clean && make build

Requirements

macOS

• Neovim (uses Neovim-specific APIs)
• macOS (uses macOS Text Input Source framework)
• Go 1.19+ (for building the binary)
• CGO enabled (uses macOS system APIs)
• Xcode Command Line Tools (xcode-select --install)

Linux

• Neovim (uses Neovim-specific APIs)
• Go 1.19+ (for building the binary)
• Input Method Framework: One of:
  • IBus (ibus-daemon)
  • Fcitx (fcitx)
  • Fcitx5 (fcitx5)
  • XKB (setxkbmap - built into X11/Wayland)

Windows

• Neovim (uses Neovim-specific APIs)
• Windows 11 (controls IME status, doesn't change input methods)
• Go 1.19+ (for building the binary)

License

MIT License - see LICENSE file for details.

Contributing

Issues and feature requests are welcome