If the `$VISUAL` environment variable is set, it will be used as the program to edit the function. If `$VISUAL` is unset but `$EDITOR` is set, that will be used. Otherwise, a built-in editor will be used. Note that to enter a literal newline using the built-in editor you should press @key{Alt,Enter}. Pressing @key{Enter} signals that you are done editing the function. This does not apply to an external editor like emacs or vim.
- `-e command` or `--editor command` Open the function body inside the text editor given by the command (for example, `-e vi`). The special command `fish` will use the built-in editor (same as specifying `-i`).