Composing Unicode Characters

Use Emacs insert-char (C-x 8 RET)

The emacs insert-char function works well for emoji and math symbols as long as you know the right name to use. Tab completion can help.

μ C-x 8 RET greek small letter mu RET
µ C-x 8 RET b5 RET
λ C-x 8 RET greek small letter lambda RET
λ C-x 8 RET 3bb RET
🏠 C-x 8 RET house building RET

Use macOS IME

  1. Turn off the macOS keyboard shortcut for “Select the previous input source” because it conflicts with the emacs C-SPC shortcut for set-mark-command:

    System Preferences > Keyboard > Shortcuts > Input Sources

  2. In the same Input Sources preference list, turn on the “Select next source in Input menu” option (C-M-SPC) or just use the input menu to switch IMEs.

  3. Entering Unicode characters in emacs with an IME or emoji keyboard mostly works. But, terminal mode emacs (no X) can sometimes get confused about the display width of glyphs for certain codepoint sequences. In particular, newer emoji sometimes cause trouble. Entering emoji that are available through C-x 8 RET usually works okay.

  4. BBEdit is a good alternative for working with characters that confuse emacs.

Use Linux GTK+ Compose (C-S-u <hexcode> RET)

This is useful on Debian-based systems.

µ C-S-u b5 RET
° C-S-u b0 RET

See https://help.ubuntu.com/community/ComposeKey#Unicode_composition