ficd.sh/content/blog/email-in-kakoune.md

---
title: Writing Emails In Kakoune
date: 2025-06-01
---

This post will guide you through my setup for using Kakoune as an email
composer inside `aerc`. I'll also explain how to configure Kakoune to act
as the _pager_ for reading `text/plain` emails. If you only care about the
final config, feel free to skip to it [here](#final-configuration).

[TOC]

## Naive Approach

Since `aerc` uses your `$EDITOR` for composition, you don't technically
have to do anything. I prefer setting it explicitly in `aerc.conf`, for
good measure:

```ini
[compose]
editor=kak
```

The rest of the magic happens in your `kakrc`.

## Composer Setup

Essentially, we want to hook `filetype=mail` and set our buffer
configuration there. I'll share a recommended configuration with some
explanation.

```kak
hook global WinSetOption filetype=mail %~
    set-option window formatcmd '/home/fic/dev/utils/mail-utils/format.py'
    set-option window comment_line '>'
    try autospell-enable
    hook -group mail-auto-format window BufWritePre .* format
    hook -once -always window WinSetOption filetype=.* %{
        unset-option window formatcmd
        remove-hooks window mail-auto-format
    }
~
```

I use a custom formatter to format emails. It automatically hard-wraps
lines while preserving certain markup elements, code blocks, sign-offs,
and signature blocks. For more details, check the formatting section of my
post on [Helix](/blog/email/helix#formatting).

I find that setting `>` as the `comment_line` token is convenient for
working with quotes in replies.

The `try autospell-enable` enables my
[kak-autospell](https://codeberg.org/ficd/kak-autospell) plugin for the
buffer. Essentially, it provides spellchecking that's continuously
refreshed and hidden in insert mode.

The remaining commands configure auto-formatting on save. I always prefer
having this on so I never forget to format my message before sending it.

## Reader Setup

I find that using Kakoune to **read** emails is helpful because of how
easy it is to copy quotes, open links, etc. Configuring this is a tad
hackier, however. The basic idea is to set Kakoune as the viewer `pager`
in `aerc.conf`.

However, all this does is pipe the email to `kak` through standard input,
so we need to tell the editor to treat it like an email:

```ini
[viewer]
pager=kak -e 'set buffer filetype mail'
```

When you're using Kakoune as a pager, you'll probably want to configure
some things differently. In my case, I like to set the buffer as
`readonly`, remove the `number-lines` and `show-whitespaces` highlighters,
disable soft-wrap & my scrolloff settings, and _not_ set any formatters.

The `pager` command above sets the filetype, but we need to distinguish
between _composing_ and _reading_ in our Kakoune hook. When Kakoune is
opened with input through standard input, it loads a buffer that's
conveniently named `*stdin*`. Thus, we can check the buffer name before
continuing.

If we're in "reading mode", we define a hidden command called
`ismailreader` which doesn't do anything. Why? If the command is defined,
and we try to invoke it... well, nothing happens! But if it's **not**
defined, we get an error instead. We can combine this with the `try`
command to for some simple boolean logic.

```kak
evaluate-commands %sh{
    # stdin, we assume it's a pager
    if [ "$kak_bufname" = "*stdin*" ]; then
        echo 'define-command -hidden ismailreader nop'
    fi
}
try %{
  ismailreader
  # do reader config here
} catch %{
  # do composer config here
}
```

I set the following configuration for "reader mode":

```kak
set buffer readonly true
try %{
	remove-highlighter window/number-lines
	remove-highlighter window/show-whitespaces
	# custom commands defined elsewhere in my kakrc
	ui-wrap-disable
	ui-scrolloff-disable
}
```

## Final Configuration

To recap, you'll want to set this in `aerc.conf`:

```ini
[viewer]
pager=kak -e 'set buffer filetype mail'

# ...

[compose]
editor=kak
```

And the following in your `kakrc`:

```kak
hook global WinSetOption filetype=mail %~
    evaluate-commands %sh{
        # stdin, we assume it's a pager
        if [ "$kak_bufname" = "*stdin*" ]; then
            echo 'define-command -hidden ismailreader nop'
        fi
    }
    try %{
        # READER MODE setup
        ismailreader
        set buffer readonly true
    	try %{
    		# remove these highlighters so everything displays properly
    		remove-highlighter window/number-lines
    		remove-highlighter window/show-whitespaces
    		ui-wrap-disable
    		ui-scrolloff-disable
    	}
    } catch %{
        # WRITER MODE setup
        set-option window formatcmd '/home/fic/dev/utils/mail-utils/format.py'
        set-option window comment_line '>'
        try autospell-enable
        hook -group mail-auto-format window BufWritePre .* format
        hook -once -always window WinSetOption filetype=.* %{
            unset-option window formatcmd
            remove-hooks window mail-auto-format
        }
    }
~
```