squirrel

Squirrel is the macOS version of the Rime Input Method Engine. An input method is software that lets users type characters from writing systems like Chinese by pressing keys on a standard keyboard. The user types phonetic or structural codes, and the input method converts them into the correct characters on screen. Squirrel supports macOS 13.0 and above.

Rime is the underlying engine shared across platforms. Squirrel is its macOS front-end. The same engine powers two other official distributions: one for Linux available as ibus-rime or fcitx-rime (called Zhongzheyun), and one for Windows (called Weasel or Xiaolanghao).

After installing, users switch to Squirrel from the macOS input method menu by selecting its icon. The keyboard shortcut Ctrl+backtick or F4 opens a scheme selector for switching between input styles, such as Pinyin romanization or the Zhuyin phonetic notation system. Customization is done by editing user configuration files, then choosing "Redeploy" from the menu for changes to take effect. If some applications cannot accept text immediately after a fresh install, logging out and back in resolves the issue.

Additional input schemes beyond the defaults can be installed using a companion configuration tool called Plum. Full documentation is available on the project website at rime.im. Bugs and suggestions can be reported to the Rime community discussion board on GitHub.

Squirrel is open source under the GPL v3 license. It is built on top of the librime engine along with several other open-source libraries including Boost, LevelDB, OpenCC, and yaml-cpp.