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2023-09-18 Emacs news

| emacs, emacs-news

Links from, r/orgmode, r/spacemacs, r/planetemacs, Hacker News,, kbin,,, lemmy,, YouTube, the Emacs NEWS file, Emacs Calendar, and emacs-devel. Thanks to Andrés Ramírez for emacs-devel links. Do you have an Emacs-related link or announcement? Please e-mail me at Thank you!

EmacsConf backstage: making it easier to do talk-specific actions

| emacs, emacsconf

During an EmacsConf talk, we:

  • copy the talk overlay images and use them in the streaming software (OBS)
  • play videos
    • a recorded introduction if it exists
    • any extra videos we want to play
    • the main talk
  • and open up browser windows
    • the BigBlueButton web conference room for a live Q&A session
    • the talk's Etherpad collaborative document for questions
    • the Internet Relay Chat channel, if that's where the speaker wants to handle questions

To minimize the work involved in copying and pasting filenames and URLs, I wanted to write scripts that could perform the right action given the talk ID. I automated most of it so that it could work from Emacs Lisp, and I also wrote shell scripts so that I (or someone else) could run the appropriate commands from the terminal.

The shell scripts are in the emacsconf-ansible repository and the Emacs Lisp functions are in emacsconf-stream.el.

Change the image overlay

We display the conference logo, talk title, and speaker name on the screen while the video is playing. This is handled with an OBS scene that includes whatever image is at ~/video.png or ~/other.png, since that results in a nicer display than using text in OBS. I'll go into how we make the overlay images in a different blog post. This post focuses on including the right image, which is just a matter of copying the right file over ~/video.png.

Figure 1: Sample overlay file
Figure 2: OBS scene with the overlay

This is copied by set-overlay.

if [[ ! -f $FILE ]]; then
SLUG=$(echo "$FILE" | perl -ne 'if (/^emacsconf-[0-9]*-(.*?)--/) { print $1; } else { print; }')
if [[ -f /data/emacsconf/assets/overlays/$SLUG-other.png ]]; then
    echo "Found other overlay for $SLUG, copying"
    cp /data/emacsconf/assets/overlays/$SLUG-other.png ~/other.png
    echo "Could not find /data/emacsconf/assets/overlays/$SLUG-other.png, please override ~/other.png manually"
    cp /data/emacsconf/assets/overlays/blank-other.png ~/other.png
if [[ -f /data/emacsconf/assets/overlays/$SLUG-video.png ]]; then
    echo "Found video overlay for $SLUG, copying"
    cp /data/emacsconf/assets/overlays/$SLUG-video.png ~/video.png
    echo "Could not find /data/emacsconf/assets/overlays/$SLUG-video.png, override ~/video.png manually"
    cp /data/emacsconf/assets/overlays/blank-video.png ~/video.png

set-overlay is called by the Emacs Lisp function emacsconf-stream-set-overlay:

emacsconf-stream-set-overlay: Reset the overlay for TALK, just in case.
(defun emacsconf-stream-set-overlay (talk)
  "Reset the overlay for TALK, just in case.
With a prefix argument (\\[universal-argument]), clear the overlay."
  (interactive (list
                (if current-prefix-arg
   (emacsconf-get-track talk)
   (if current-prefix-arg
     (plist-get talk :slug))))

Play the intro video or display the intro slide

Figure 3: Sample intro slide

We wanted to display the talk titles, speaker names, and URLs for both the previous talk and the next talk. We generated all the intro slides, and then as time permitted, we recorded introduction videos so that we could practise saying people's names instead of panicking during a full day. Actually generating the intro slide or video is a topic for another blog post. This post just focuses on playing the appropriate video or displaying the right image, which is handled by the intro script.

# Kill the background music if playing
if screen -list | grep -q background; then
    screen -S background -X quit
# Update the overlay
if [[ ! -f $FILE ]]; then
    SLUG=$(echo "$FILE" | perl -ne 'if (/emacsconf-[0-9]*-(.*?)--/) { print $1; } else { print; }')
overlay $SLUG
if [[ -f /data/emacsconf/assets/intros/$SLUG.webm ]]; then
  mpv /data/emacsconf/assets/intros/$SLUG.webm
  firefox /data/emacsconf/assets/in-between/$SLUG.png

This is easy to call from Emacs Lisp.

emacsconf-stream-play-intro: Play the recorded intro or display the in-between slide for TALK.
(defun emacsconf-stream-play-intro (talk)
  "Play the recorded intro or display the in-between slide for TALK."
  (interactive (list (emacsconf-complete-talk-info)))
  (setq talk (emacsconf-resolve-talk talk))
  (emacsconf-stream-track-ssh talk "nohup" "intro" (plist-get talk :slug)))

Play just the video

Sometimes we might need to restart a video without playing the introduction again. The ready-to-stream videos are all in one directory following the naming convention emacsconf-year-slug--title--speakers--main.webm. We update the --main.webm video as we go through the process of reencoding the video, normalizing sound, and adding captions. We can play the latest video by doing a wildcard match based on the slug.


# Play intro if recorded, then play files

# Kill the background music if playing
if screen -list | grep -q background; then
    screen -S background -X quit

# Update the overlay
if [[ ! -f $FILE ]]; then
SLUG=$(echo "$FILE" | perl -ne 'if (/emacsconf-[0-9]*-(.*?)--/) { print $1; } else { print; }')
overlay $SLUG
mpv $FILE $* &

emacsconf-stream-play-video: Play just the video for TALK.
(defun emacsconf-stream-play-video (talk)
  "Play just the video for TALK."
  (interactive (list (emacsconf-complete-talk-info)))
  (setq talk (emacsconf-resolve-talk talk))
   talk "nohup" "play" (plist-get talk :slug)))

Play the intro and then the video

The easiest way to go through a talk is to play the introduction and the video without further manual intervention. This shell script updates the overlay, plays the intro if available, and then continues with the video.


# Play intro if recorded, then play files

# Kill the background music if playing
if screen -list | grep -q background; then
    screen -S background -X quit

# Update the overlay
if [[ ! -f $FILE ]]; then
SLUG=$(echo "$FILE" | perl -ne 'if (/emacsconf-[0-9]*-(.*?)--/) { print $1; } else { print; }')
overlay $SLUG
# Play the video
if [[ -f /data/emacsconf/assets/intros/$SLUG.webm ]]; then
    intro $SLUG
mpv $FILE $* &

Along the lines of minimizing manual work, this more complex Emacs Lisp function considers different combinations of intros and talks:

  Recorded intro Live intro
Recorded talk automatically play both show intro slide; remind host to play video
Live talk play intro; host joins BBB join BBB room automatically

emacsconf-stream-play-talk-on-change: Play the talk.
(defun emacsconf-stream-play-talk-on-change (talk)
  "Play the talk."
  (interactive (list (emacsconf-complete-talk-info)))
  (setq talk (emacsconf-resolve-talk talk))
  (when (or (not (boundp 'org-state)) (string= org-state "PLAYING"))
    (if (plist-get talk :stream-files)
           (plist-get talk :slug))
            (split-string-and-unquote (plist-get talk :stream-files))
            (list "&"))))
           (plist-get talk :recorded-intro)
           (plist-get talk :video-file)) ;; recorded intro and recorded talk
          (message "should automatically play intro and recording")
          (list "play-with-intro" (plist-get talk :slug))) ;; todo deal with stream files
           (plist-get talk :recorded-intro)
           (null (plist-get talk :video-file))) ;; recorded intro and live talk; play the intro and join BBB
          (message "should automatically play intro; join %s" (plist-get talk :bbb-backstage))
          (list "intro" (plist-get talk :slug)))
           (null (plist-get talk :recorded-intro))
           (plist-get talk :video-file)) ;; live intro and recorded talk, show slide and use Mumble; manually play talk
          (message "should show intro slide; play %s afterwards" (plist-get talk :slug))
          (list "intro" (plist-get talk :slug)))
           (null (plist-get talk :recorded-intro))
           (null (plist-get talk :video-file))) ;; live intro and live talk, join the BBB
          (message "join %s for live intro and talk" (plist-get talk :bbb-backstage))
          (list "bbb" (plist-get talk :slug)))))))))

Open the Etherpad

We used Etherpad collaborative documents to collect people's questions during the conference. I made an index page that linked to the Etherpads for the different talks so that I could open it in the browser used for streaming.

Figure 4: Backstage index

I also had an Emacs Lisp function that opened up the pad in the appropriate stream.

emacsconf-stream-open-pad: Open the Etherpad collaborative document for TALK.
(defun emacsconf-stream-open-pad (talk)
  "Open the Etherpad collaborative document for TALK."
  (interactive (list (emacsconf-complete-talk-info)))
  (setq talk (emacsconf-resolve-talk talk))
   (plist-get talk :pad-url)))

I think I'll add a shell script to make it more consistent, too.


# Display the Etherpad collaborative document

# Update the overlay
overlay $SLUG

Open the Big Blue Button web conference

Most Q&A sessions are done live through a BigBlueButton web conference. We use redirects to make it easier to go to the talk URL. Backstage redirects are protected by a username and password which is shared with volunteers and saved in the browser used for streaming.


# Open the Big Blue Button room using the backstage link

# Kill the background music if playing
if screen -list | grep -q background; then
    screen -S background -X quit

# Update the overlay
overlay $SLUG

Public redirect URLs start off with a refresh loop and then are overwritten with a redirect to the actual page when the host is okay with opening up the Q&A for general participation. This is done by changing the TODO status of the talk from CLOSED_Q to OPEN_Q.

emacsconf-publish-bbb-redirect: Update the publicly-available redirect for TALK.
(defun emacsconf-publish-bbb-redirect (talk &optional status)
  "Update the publicly-available redirect for TALK."
  (interactive (list (emacsconf-complete-talk-info)))
  (let ((bbb-filename (expand-file-name (format "bbb-%s.html" (plist-get talk :slug))
        (bbb-redirect-url (concat "" emacsconf-year "/current/bbb-" (plist-get talk :slug) ".html"))
        (status (or status (emacsconf-bbb-status (if (boundp 'org-state) (append (list :status org-state) talk) talk)))))
    (with-temp-file bbb-filename
        (append talk (list :base-url emacsconf-base-url :bbb-redirect-url bbb-redirect-url))
        (pcase status
           "<html><head><meta http-equiv=\"refresh\" content=\"0; URL=${bbb-room}\"></head><body>
The live Q&A room for ${title} is now open. You should be redirected to <a href=\"${bbb-room}\">${bbb-room}</a> automatically, but if not, please visit the URL manually to join the Q&A.</body></html>")
           "<html><head><meta http-equiv=\"refresh\" content=\"5; URL=${bbb-redirect-url}\"></head><body>
The Q&A room for ${title} is not yet open. This page will refresh every 5 seconds until the BBB room is marked as open, or you can refresh it manually.</body></html>")
The Q&A room for ${title} has finished. You can find more information about the talk at <a href=\"${base-url}${url}\">${base-url}${url}</a>.</body></html>")
There is no live Q&A room for ${title}. You can find more information about the talk at <a href=\"${base-url}${url}\">${base-url}${url}</a>.</body></html>"

Open up the stream chat

The IRC chat is the same for the whole track instead of changing for each talk. Since we might close the window, it's useful to be able to quickly open it again.

emacsconf-stream-join-chat: Join the IRC chat for TALK.
(defun emacsconf-stream-join-chat (talk)
  "Join the IRC chat for TALK."
  (interactive (list (emacsconf-complete-talk-info)))
  (setq talk (emacsconf-resolve-talk talk))
   (plist-get talk :webchat-url)))

Set up for the right Q&A type

An Emacs Lisp function makes it easier to do the right thing depending on the type of Q&A planned for the talk.

emacsconf-stream-join-qa: Join the Q&A for TALK.
(defun emacsconf-stream-join-qa (talk)
  "Join the Q&A for TALK.
This uses the BBB room if available, or the IRC channel if not."
  (interactive (list (emacsconf-complete-talk-info)))
  (if (and (null (plist-get talk :video-file))
           (string-match "live" (plist-get talk :q-and-a)))
       (plist-get talk :pad-url)) 
     (pcase (plist-get talk :q-and-a)
       ((or 'nil "" (rx "Mumble"))
        (plist-get talk :qa-slide-url))
       ((rx "live")
        (plist-get talk :bbb-backstage))
       ((rx "IRC")
        (plist-get talk :webchat-url))
       ((rx "pad")
        (plist-get talk :pad-url))
       (_ (plist-get talk :qa-slide-url))))))


Combining shell scripts (roles/obs/templates) and Emacs Lisp functions (emacsconf-stream.el) help us simplify the work of taking talk-specific actions that depend on the kind of talk or Q&A session. Using simple identifiers and consistent file name conventions means that we can refer to talks quickly and use wildcards in shell scripts.

We started the conference with me jumping around and running most of the commands, since I had hastily written them in the weeks leading up to the conference and I was the most familiar with them. As the conference went on, other organizers got the hang of the commands and took over running their streams. Yay!

2023-09-11 Emacs news

| emacs, emacs-news

Links from, r/orgmode, r/spacemacs, r/planetemacs, Hacker News,, kbin,,, lemmy,, YouTube, the Emacs NEWS file, Emacs Calendar, and emacs-devel. Thanks to Andrés Ramírez for emacs-devel links. Do you have an Emacs-related link or announcement? Please e-mail me at Thank you!

EmacsConf backstage: jumping to and working with talks using Embark

| emacs, emacsconf

In the course of organizing and running EmacsConf, I often need to jump to or act on specific talks. I have a function that jumps to the talk heading so that I can look up additional information or add notes.

Figure 1: Jumping to a talk

emacsconf-go-to-talk: Jump to the talk heading matching SEARCH.
(defun emacsconf-go-to-talk (search)
  "Jump to the talk heading matching SEARCH."
  (interactive (list (emacsconf-complete-talk)))
  (find-file emacsconf-org-file)
   ((plist-get search :slug)
    (goto-char (org-find-property "SLUG" (plist-get search :slug))))
   ((emacsconf-get-slug-from-string search)
    (goto-char (org-find-property "SLUG" (emacsconf-get-slug-from-string search))))
     (catch 'found
        (lambda ()
          (when (string-match search
                               (concat (org-entry-get (point) "SLUG") " - "
                                       (org-entry-get (point) "ITEM") " - "
                                       (org-entry-get (point) "NAME") " - "
                                       (org-entry-get (point) "EMAIL"))
            (throw 'found (point))))

Most of the work is done in a completion function that makes it easy to specify a talk using the slug (talk ID), title, or speaker names.

emacsconf-complete-talk: Offer talks for completion.
(defun emacsconf-complete-talk (&optional info)
  "Offer talks for completion.
If INFO is specified, limit it to that list."
  (let ((choices
         (if (and (null info) emacsconf-complete-talk-cache)
           (mapcar (lambda (o)
                      (delq nil
                            (mapcar (lambda (f) (plist-get o f))
                                    '(:slug :title :speakers :irc)))
                      " - "))
                   (or info (emacsconf-get-talk-info))))))
     "Talk: " 
     (lambda (string predicate action)
       (if (eq action 'metadata)
           '(metadata (category . emacsconf))
         (complete-with-action action choices string predicate))))))

In addition to jumping to the Org heading for a talk, there are a bunch of other things I might want to do. Embark lets me add a bunch of shortcuts for working with a talk. I could open the caption file, edit the talk's wiki page, change a talk's property, e-mail the speaker, or more. Here's the Embark-related code from emacsconf.el:

Embark-related code
;;; Embark
(defun emacsconf-embark-finder ()
  "Identify when we're on a talk subtree."
  (when (and (derived-mode-p 'org-mode)
             (org-entry-get-with-inheritance "SLUG"))
    (cons 'emacsconf (org-entry-get-with-inheritance "SLUG"))))

(defun emacsconf-insert-talk-title (search)
  "Insert the talk title matching SEARCH."
  (interactive (list (emacsconf-complete-talk)))
  (insert (plist-get (emacsconf-search-talk-info search) :title)))

(with-eval-after-load 'embark
  (add-to-list 'embark-target-finders 'emacsconf-embark-finder)
  (defvar-keymap embark-emacsconf-actions
    :doc "Keymap for emacsconf-related things"
    "a" #'emacsconf-announce
    "c" #'emacsconf-find-captions-from-slug
    "d" #'emacsconf-find-caption-directives-from-slug
    "p" #'emacsconf-set-property-from-slug
    "w" #'emacsconf-edit-wiki-page
    "s" #'emacsconf-set-start-time-for-slug
    "W" #'emacsconf-browse-wiki-page
    "u" #'emacsconf-update-talk
    "t" #'emacsconf-insert-talk-title
    "m" #'emacsconf-mail-speaker-from-slug
    "n" #'emacsconf-notmuch-search-mail-from-entry
    "f" #'org-forward-heading-same-level
    "b" #'org-backward-heading-same-level
    "RET" #'emacsconf-go-to-talk)
  (add-to-list 'embark-keymap-alist '(emacsconf . embark-emacsconf-actions)))

;;; Status updates

For example, I sometimes need to open the wiki page for a talk in order to update the talk description.

emacsconf-edit-wiki-page: Open the wiki page for the talk matching SEARCH.
;;; Embark
(defun emacsconf-embark-finder ()
  "Identify when we're on a talk subtree."
  (when (and (derived-mode-p 'org-mode)
             (org-entry-get-with-inheritance "SLUG"))
    (cons 'emacsconf (org-entry-get-with-inheritance "SLUG"))))

Embark can also act on completion candidates, so I can call any of those actions from my C-c e t shortcut for emacsconf-go-to-talk. This is specified by the (metadata (category . emacsconf)) in emacsconf-complete-talk and the (add-to-list 'embark-keymap-alist '(emacsconf . embark-emacsconf-actions)) in my Embark configuration.

C-. is the embark-act shortcut in my configuration. When I need to remember what the shortcuts are, I can use C-h (embark-keymap-help) to list the keyboard shortcuts or select the command with completion.

Figure 2: Embark help for Emacsconf talks

The code above and related functions are in emacsconf.el or other files in the emacsconf-el repository.

EmacsConf backstage: scheduling with SVGs

| emacs, emacsconf

The EmacsConf 2023 call for participation deadline is coming up next Friday (Sept 15), so I'm getting ready to draft the schedule.

Here's a quick overview of how I experiment with schedules for EmacsConf. I have all the talk details in Org subtrees. There's a SLUG property that has the talk ID, a TIME property that says how long a talk is, and a Q_AND_A property that says what kind of Q&A the speaker wants: live, IRC, Etherpad, or after the event. Some talks have fixed starting times, like the opening remarks. Others start when the Q&A for the previous session ends. I generate an SVG so that I can quickly see how the schedule looks. Are there big gaps? Did I follow everyone's availability constraints? Does the schedule flow reasonably logically?

Code to define a schedule
(require 'emacsconf-schedule)
(setq emacsconf-schedule-tracks
      '((:label "Saturday"
                :start "2023-12-02 9:00"
                :end "2023-12-02 18:00"
                :tracks ("General"))
        (:label "Sunday"
                :start "2023-12-03 9:00"
                :end "2023-12-03 18:00"
                :tracks ("General"))))
(setq emacsconf-schedule-default-buffer-minutes 10
      emacsconf-schedule-default-buffer-minutes-for-live-q-and-a 30
      emacsconf-schedule-break-time 10
      emacsconf-schedule-lunch-time 60
      emacsconf-schedule-max-time 30
(setq emacsconf-schedule-plan
      '(("GEN Saturday, Dec 2" :start "2023-12-02 09:00")
        adventure writing one uni lunch hyperdrive ref mentor flat        (hn :start "15:30")
        (web :start "16:00") 
        ("GEN Sunday, Dec 3" :start "2023-12-03 09:00")
        windows extending lunch lspocaml sharing emacsen
        voice llm))
(setq emacsconf-schedule-draft (emacsconf-schedule-prepare (emacsconf-schedule-inflate-sexp emacsconf-schedule-plan)))
(emacsconf-schedule-validate emacsconf-schedule-draft)
(let ((emacsconf-schedule-svg-modify-functions
  (with-temp-file "schedule.svg"
    (svg-print (emacsconf-schedule-svg 800 200 emacsconf-schedule-draft))))
Figure 1: Sample schedule draft

Common functions are in emacsconf-schedule.el in the emacsconf-el repository, while conference-specific code is in our private file.


I was working on the schedule for EmacsConf 2022 when I ran into a problem. I wanted more talks than could fit into the time that we had, even if I scheduled it as tightly as possible with just a few minutes of transition between talks. This had been the scheduling strategy we used in previous years, squishing all the talks together with just enough time to let people know where they could go to ask questions. We had experimented with an alternate track for Q&A during EmacsConf 2021, so that had given us a little more space for discussion, but it wasn't going to be enough to fit in all the talks we wanted for EmacsConf 2022.

Could I convince the other organizers to take on the extra work needed for a multi-track conference? I knew it would be a lot of extra technical risk, and we'd need another host and streamer too. Could I make the schedule easy to understand on the wiki if we had two tracks? The Org Mode table I'd been using for previous years was not going to be enough. I was getting lost in the text.

Figure 2: Scheduling using Org Mode tables

Visualizing the schedule as an SVG

I'd been playing around with SVGs in Emacs. It was pretty straightforward to write a function that used time for the X axis and displayed different tracks. That showed us how full the conference was going to be if I tried to pack everything into two days.

Figure 3: One full day

emacsconf-schedule-svg-track: Draw the actual rectangles and text for the talks.
(defun emacsconf-schedule-svg-track (svg base-x base-y width height start-time end-time info)
  "Draw the actual rectangles and text for the talks."
  (let ((scale (/ width (float-time (time-subtract end-time start-time)))))
     (lambda (o)
       (let* ((offset (floor (* scale (float-time (time-subtract (plist-get o :start-time) start-time)))))
              (size (floor (* scale (float-time (time-subtract (plist-get o :end-time) (plist-get o :start-time))))))
              (x (+ base-x offset))
              (y base-y)
              (node (dom-node
                      (cons 'x x)
                      (cons 'y y)
                      (cons 'opacity "0.8")
                      (cons 'width size)
                      (cons 'height (1- height))
                      (cons 'stroke "black")
                      (cons 'stroke-dasharray
                            (if (string-match "live" (or (plist-get o :q-and-a) "live"))
                      (cons 'fill
                             ((string-match "BREAK\\|LUNCH" (plist-get o :title)) "white")
                             ((plist-get o :invalid) "red")
                             ((string-match "EST"
                                            (or (plist-get o :availability) ""))
                             (t "lightgreen"))))))
              (parent (dom-node
                        (cons 'href
                               (if emacsconf-use-absolute-url
                               (plist-get o :url)))
                        (cons 'title (plist-get o :title))
                        (cons 'data-slug (plist-get o :slug)))
                       (dom-node 'title nil
                                 (concat (format-time-string "%l:%M-" (plist-get o :start-time) emacsconf-timezone)
                                         (format-time-string "%l:%M " (plist-get o :end-time) emacsconf-timezone)
                                         (plist-get o :title)))
                        `((transform . ,(format "translate(%d,%d)"
                                                (+ x size -2) (+ y height -2))))
                          (cons 'fill "black")
                          (cons 'x 0)
                          (cons 'y 0)
                          (cons 'font-size 10)
                          (cons 'transform "rotate(-90)"))
                         (svg--encode-text (or (plist-get o :slug) (plist-get o :title))))))))
          o node parent)

emacsconf-schedule-svg-day: Add the time scale and the talks on a given day.
(defun emacsconf-schedule-svg-day (elem label width height start end tracks)
  "Add the time scale and the talks on a given day."
  (let* ((label-margin 15)
         (track-height (/ (- height (* 2 label-margin)) (length tracks)))
         (x 0) (y label-margin)
         (scale (/ width (float-time (time-subtract end start))))
         (time start))
    (dom-append-child elem (dom-node 'title nil (concat "Schedule for " label)))
    (svg-rectangle elem 0 0 width height :fill "white")
    (svg-text elem label :x 3 :y (- label-margin 3) :fill "black" :font-size "10")
    (mapc (lambda (track)
             elem x y width track-height
             start end track)
            (setq y (+ y track-height)))
    ;; draw grid
    (while (time-less-p time end)
      (let ((x (* (float-time (time-subtract time start)) scale)))
          `((transform . ,(format "translate(%d,%d)" x label-margin)))
           `((stroke . "darkgray")
             (x1 . 0)
             (y1 . 0)
             (x2 . 0)
             (y2 . ,(- height label-margin label-margin))))
           `((fill . "black")
             (x . 0)
             (y . ,(- height 2 label-margin))
             (font-size . 10)
             (text-anchor . "left"))
           (svg--encode-text (format-time-string "%-l %p" time emacsconf-timezone)))))
        (setq time (time-add time (seconds-to-time 3600)))))

emacsconf-schedule-svg-days: Display multiple days.
(defun emacsconf-schedule-svg-days (width height days)
  "Display multiple days."
  (let ((svg (svg-create width height))
        (day-height (/ height (length days)))
        (y 0))
    (dom-append-child svg (dom-node 'title nil "Graphical view of the schedule"))
     (lambda (day)
       (let ((group (dom-node 'g `((transform . ,(format "translate(0,%d)" y))))))
         (dom-append-child svg group)
         (emacsconf-schedule-svg-day group
                   (plist-get day :label)
                   width day-height
                   (date-to-time (plist-get day :start))
                   (date-to-time (plist-get day :end))
                   (plist-get day :tracks)))
       (setq y (+ y day-height)))

emacsconf-schedule-svg: Make the schedule SVG for INFO.
(defun emacsconf-schedule-svg (width height &optional info)
  "Make the schedule SVG for INFO."
  (setq info (emacsconf-prepare-for-display (or info (emacsconf-get-talk-info))))
  (let ((days (seq-group-by (lambda (o)
                              (format-time-string "%Y-%m-%d" (plist-get o :start-time) emacsconf-timezone))
                            (sort (seq-filter (lambda (o)
                                                (or (plist-get o :slug)
                                                    (plist-get o :include-in-info)))
     width height
     (mapcar (lambda (o)
               (let ((start (concat (car o) "T" emacsconf-schedule-start-time emacsconf-timezone-offset))
                     (end (concat (car o) "T" emacsconf-schedule-end-time emacsconf-timezone-offset)))
                 (list :label (format-time-string "%A" (date-to-time (car o)))
                       :start start
                       :end end
                       :tracks (emacsconf-by-track (cdr o)))))

With that, I was able to show the other organizers what a two-track conference could look like.

Figure 4: Two-track conference
Defining a schedule with two tracks
 (emacsconf-time-constraints '(("LUNCH" "11:30" "13:30")))
 (emacsconf-schedule-default-buffer-minutes 15)
 (emacsconf-schedule-default-buffer-minutes-for-live-q-and-a 25)
   '(("GEN Saturday, December 3" . "2022-12-03 09:00")
     "Saturday opening remarks"
     survey orgyear rolodex
     links buttons 
     hyperorg        realestate    health 
     jupyter workflows
     ("Saturday closing remarks" . "2022-12-03 17:00")
     ("GEN Sunday, December 4" . "2022-12-04 09:00")
     "Sunday opening remarks"
               school  science   lunch
               meetups buddy
      orgvm indieweb  fanfare
     ("Sunday closing remarks" . "2022-12-04 17:00")
     ("DEV Saturday, December 3" . "2022-12-03 10:00")
     localizing  treesitter lspbridge
     lunch sqlite
mail     eev python break wayland (haskell . "2022-12-03 16:00")
     ("DEV Sunday, December 4" . "2022-12-04 10:00")
     justl eshell 
     detached rde 
                tramp async
     asmblox dbus maint           )) )
 (emacsconf-schedule-break-time 10)
 (emacsconf-schedule-lunch-time 60)
 (emacsconf-schedule-max-time 30)
 (emacsconf-schedule-tweaked-allocations '(("indieweb" . 20)
                                           ("maint" . 20)
                                           ("workflows" . 20)))
 (emacsconf-scheduling-strategies '(emacsconf-schedule-override-breaks
 (tracks '((:label "Saturday"
                   :start "2022-12-03 9:00"
                   :end "2022-12-03 18:00"
                   :tracks (("^GEN Sat" "^GEN Sun")
                            ("^DEV Sat" "^DEV Sun")))
          (:label "Sunday"
                  :start "2022-12-04 9:00"
                  :end "2022-12-04 18:00"
                  :tracks (("^GEN Sun" "^DEV Sat")
                           ("^DEV Sun"))))))

When the other organizers saw the two schedules, they were strongly in favour of the two-track option. Yay!

Changing scheduling strategies

As I played around with the schedule, I wanted a quick way to test different scheduling strategies, such as changing the length of Q&A sessions for live web conferences versus IRC/Etherpad/email Q&A. Putting those into variables allowed me to easily override them with a let form, and I used a list of functions to calculate or modify the schedule from the Org trees.

Figure 5: Changing the default Q&A times

emacsconf-schedule-allocate-buffer-time: Allocate buffer time based on whether INFO has live Q&A.
(defun emacsconf-schedule-allocate-buffer-time (info)
  "Allocate buffer time based on whether INFO has live Q&A.
Uses `emacsconf-schedule-default-buffer-minutes' and
  (mapcar (lambda (o)
            (when (plist-get o :slug)
              (unless (plist-get o :buffer)
                (plist-put o :buffer
                            (if (string-match "live" (or (plist-get o :q-and-a) "live"))

This is actually applied by emacsconf-schedule-prepare, which runs through the list of strategies defined in emacsconf-schedule-strategies.

emacsconf-schedule-prepare: Apply ‘emacsconf-schedule-strategies’ to INFO to determine the schedule.
(defun emacsconf-schedule-prepare (&optional info)
  "Apply `emacsconf-schedule-strategies' to INFO to determine the schedule."
   (seq-reduce (lambda (prev val) (funcall val prev))
               (or info (emacsconf-get-talk-info)))))

Type of Q&A

I wanted to see which sessions had live Q&A via web conference and which ones had IRC/Etherpad/asynchronous Q&A. I set the talk outlines so that dashed lines mean asynchronous Q&A and solid lines mean live. Live Q&As take a little more work on our end because the host starts it up and reads questions, but they're more interactive. This is handled by

(cons 'stroke-dasharray
      (if (string-match "live" (or (plist-get o :q-and-a) "live"))

in the emacsconf-schedule-svg-track function.

Moving talks around

I wanted to be able to quickly reorganize talks by moving their IDs around in a list instead of just using the order of the subtrees in my Org Mode file. I wrote a function that took a list of symbols, looked up each of the talks, and returned a list of talk info property lists. I also added the ability to override some things about talks, such as whether something started at a fixed time.

emacsconf-schedule-inflate-sexp: Takes a list of talk IDs and returns a list that includes the scheduling info.
(defun emacsconf-schedule-inflate-sexp (sequence &optional info include-time)
  "Takes a list of talk IDs and returns a list that includes the scheduling info.
Pairs with `emacsconf-schedule-dump-sexp'."
  (setq info (or info (emacsconf-get-talk-info)))
  (let ((by-assoc (mapcar (lambda (o) (cons (intern (plist-get o :slug)) o))
                          (emacsconf-filter-talks info)))
     (lambda (seq)
       (unless (listp seq) (setq seq (list seq)))
       (if include-time
           (error "Not yet implemented")
         (let ((start-prop (or (plist-get (cdr seq) :start)
                               (and (stringp (cdr seq)) (cdr seq))))
               (time-prop (or (plist-get (cdr seq) :time) ; this is duration in minutes
                              (and (numberp (cdr seq)) (cdr seq))))
               (track-prop (plist-get (cdr seq) :track)))
            ;; overriding 
            (when start-prop
              (if (string-match "-" start-prop)
                  (setq date (format-time-string "%Y-%m-%d" (date-to-time start-prop)))
                (setq start-prop  (concat date " " start-prop)))
               :scheduled (format-time-string (cdr org-time-stamp-formats) (date-to-time start-prop)
               :start-time (date-to-time start-prop)
               :fixed-time t))
            (when track-prop
              (list :track track-prop))
            (when time-prop
              (list :time (if (numberp time-prop) (number-to-string time-prop) time-prop)))
            ;; base entity
             ((eq (car seq) 'lunch)
              (list :title "LUNCH" :time (number-to-string emacsconf-schedule-lunch-time)))
             ((eq (car seq) 'break)
              (list :title "BREAK" :time (number-to-string emacsconf-schedule-break-time)))
             ((symbolp (car seq))
              (assoc-default (car seq) by-assoc))
             ((stringp (car seq))
              (or (seq-find (lambda (o) (string= (plist-get o :title) (car seq))) info)
                  (list :title (car seq))))
             (t (error "Unknown %s" (prin1-to-string seq))))))))

That allowed me to specify a test schedule like this:

(setq emacsconf-schedule-plan
      '(("GEN Saturday, Dec 2" :start "2023-12-02 09:00")
        adventure writing one uni lunch hyperdrive ref mentor flat
        (hn :start "15:30")
        (web :start "16:00") 
        ("GEN Sunday, Dec 3" :start "2023-12-03 09:00")
        windows extending lunch lspocaml sharing emacsen
        voice llm))
(setq emacsconf-schedule-draft
       (emacsconf-schedule-inflate-sexp emacsconf-schedule-plan)))

Validating the schedule

Now that I could see the schedule visually, it made sense to add some validation. As mentioned in my post about timezones, I wanted to validate live Q&A against the speaker's availability and colour sessions red if they were outside the times I'd written down.

I also wanted to arrange the schedule so that live Q&A sessions didn't start at the same time, giving me a little time to switch between sessions in case I needed to help out. I wrote a function that checked if the Q&A for a session started within five minutes of the previous one. This turned out to be pretty useful, since I ended up mostly taking care of playing the videos and opening the browsers for both streams. With that in place, I could just move the talks around until everything fit well together.

emacsconf-schedule-validate-live-q-and-a-sessions-are-staggered: Try to avoid overlapping the start of live Q&A sessions.
(defun emacsconf-schedule-validate-live-q-and-a-sessions-are-staggered (schedule)
  "Try to avoid overlapping the start of live Q&A sessions.
Return nil if there are no errors."
  (when emacsconf-schedule-validate-live-q-and-a-sessions-buffer
    (let (last-end)
      (delq nil
            (mapcar (lambda (o)
                          (when (and last-end
                                      (plist-get o :end-time)
                                      (time-add last-end (seconds-to-time (* emacsconf-schedule-validate-live-q-and-a-sessions-buffer 60)))))
                            (plist-put o :invalid (format "%s live Q&A starts at %s within %d minutes of previous live Q&A at %s"
                                                          (plist-get o :slug)
                                                          (format-time-string "%m-%d %-l:%M"
                                                                              (plist-get o :end-time))
                                                          (format-time-string "%m-%d %-l:%M"
                            (plist-get o :invalid))
                        (setq last-end (plist-get o :end-time))))
                     (seq-filter (lambda (o) (string-match "live" (or (plist-get o :q-and-a) "")))
                     (lambda (a b)
                       (time-less-p (plist-get a :end-time) (plist-get b :end-time)))

Publishing SVGs in the wiki

When the schedule settled down, it made perfect sense to include the image on the schedule page as well as on each talk page. I wanted people to be able to click on a rectangle and load the talk page. That meant including the SVG in the markup and allowing the attributes in ikiwiki's HTML sanitizer. In our, I needed to add svg rect text g title line to allow, and add version xmlns x y x1 y1 x2 y2 fill font-size font-weight stroke stroke-width stroke-dasharray transform opacity to the default attributes.

Figure 6: Opening a talk from the SVG

For the public-facing pages, I wanted to colour the talks based on track. I specified the colours in emacsconf-tracks (peachpuff and skyblue) and used them in emacsconf-schedule-svg-color-by-track.

emacsconf-schedule-svg-color-by-track: Color sessions based on track.
(defun emacsconf-schedule-svg-color-by-track (o node &optional parent)
  "Color sessions based on track."
  (let ((track (emacsconf-get-track (plist-get o :track))))
    (when track
      (dom-set-attribute node 'fill (plist-get track :color)))))

I wanted talk pages to highlight the talk on the schedule so that people could easily find other sessions that conflict. Because a number of people in the Emacs community browse with Javascript turned off, I used Emacs Lisp to generate a copy of the SVG with the current talk highlighted.

emacsconf-publish-format-talk-page-schedule: Add the schedule image for TALK based on INFO.
(defun emacsconf-publish-format-talk-page-schedule (talk info)
  "Add the schedule image for TALK based on INFO."
   "\nThe following image shows where the talk is in the schedule for "
   (format-time-string "%a %Y-%m-%d" (plist-get talk :start-time) emacsconf-timezone) ". Solid lines show talks with Q&A via BigBlueButton. Dashed lines show talks with Q&A via IRC or Etherpad."
   (format "<div class=\"schedule-in-context schedule-svg-container\" data-slug=\"%s\">\n" (plist-get talk :slug))           
   (let* ((width 800) (height 150)
          (talk-date (format-time-string "%Y-%m-%d" (plist-get talk :start-time) emacsconf-timezone))
          (start (date-to-time (concat talk-date "T" emacsconf-schedule-start-time emacsconf-timezone-offset)))
          (end (date-to-time (concat talk-date "T" emacsconf-schedule-end-time emacsconf-timezone-offset)))
       (setq svg (emacsconf-schedule-svg-day
                  (svg-create width height)
                  (format-time-string "%A" (plist-get talk :start-time) emacsconf-timezone)
                  width height
                  start end
                   (seq-filter (lambda (o) (string= (format-time-string "%Y-%m-%d" (plist-get o :start-time) emacsconf-timezone)
       (mapc (lambda (node)
               (let ((rect (car (dom-by-tag node 'rect))))
                 (if (string= (dom-attr node 'data-slug) (plist-get talk :slug))
                       (dom-set-attribute rect 'opacity "0.8")
                       (dom-set-attribute rect 'stroke-width "3")
                       (dom-set-attribute (car (dom-by-tag node 'text)) 'font-weight "bold"))
                   (dom-set-attribute rect 'opacity "0.5"))))
             (dom-by-tag svg 'a))
       (svg-print svg)
   (emacsconf-format-talk-schedule-info talk) "\n\n"))

Colouring talks based on status

As the conference approached, I wanted to colour talks based on their status, so I could see how much of our schedule already had videos and even how many had been captioned. That was just a matter of adding a modifier function to change the SVG rectangle colour depending on the TODO status.

Figure 7: Changing talk colour based on status

emacsconf-schedule-svg-color-by-status: Set talk color based on status.
(defun emacsconf-schedule-svg-color-by-status (o node &optional _)
  "Set talk color based on status.
Processing: palegoldenrod,
Waiting to be assigned a captioner: yellow,
Captioning in progress: lightgreen,
Ready to stream: green,
Other status: gray"
  (unless (plist-get o :invalid)
    (dom-set-attribute node 'fill
                       (pcase (plist-get o :status)
                         ((rx (or "TO_PROCESS"
                         ((rx (or "TO_ASSIGN"))
                         ((rx (or "TO_CAPTION"))
                         ((rx (or "TO_STREAM"))
                         (_ "gray")))))


Common functions are in emacsconf-schedule.el in the emacsconf-el repository, while conference-specific code is in our private file.

Some information is much easier to work with graphically than in plain text. Seeing the schedules as images made it easier to spot gaps or errors, tinker with parameters, and communicate with other people. Writing Emacs Lisp functions to modify my data made it easier to try out different things without rearranging the text in my Org file. Because Emacs can display images inside the editor, it was easy for me to make changes and see the images update right away. Using SVG also made it possible to export the image and make it interactive. Handy technique!

EmacsConf backstage: converting timezones

| emacsconf, emacs

2023-09-07: It looks like I can use Etc/GMT-2 to mean GMT+2 - note the reversed sign.

EmacsConf is a virtual conference with speakers from all over the world. We like to plan the schedule so that the speakers can come for live Q&A sessions without having to wake up too early or stay up too late.

Timezones are tricky for me. Sometimes I mess up timezone names (like the time I misspelled Tbilisi and ended up with UTC conversion) or get the timezone conversion wrong because of daylight savings time, and it's annoying to go to a website to convert the timezones.

Fortunately, the tzc package provides a way to convert times from one timeone to another in Emacs, and it includes a list of timezones in tzc-time-zones loaded from /usr/share/zoneinfo. Here's how I use it to make organizing EmacsConf easier.

Setting the timeone with completion

To reduce data entry errors, I use completion when setting the timezone.

Figure 1: Setting the timezone

(defun emacsconf-timezone-set (timezone)
  "Set the timezone for the current Org entry."
  (interactive (list (progn (require 'tzc) (completing-read "Timezone: " tzc-time-zones))))
  (org-entry-put (point) "TIMEZONE" timezone))

Sometimes speakers specify their timezone as an offset from GMT or UTC, such as GMT+2. It turns out that I can use timezones like Etc/GMT-2 to capture that, although it's important to note that the sign for Etc/GMT timezones is reversed (so Etc/GMT-2 = GMT+2).

Converting timezones

In Toronto, we switch from daylight savings time to standard time sometime in November, so I need to make sure that my time conversions for speaker availability uses the date of the conference (emacsconf-date, 2023-12-02 this year). emacsconf-convert-from-timezone makes it easy to convert times on emacsconf-date so that I don't have to keep re-entering the date part.

Figure 2: Converting from a timezone

(defun emacsconf-convert-from-timezone (timezone time)
  (interactive (list (progn
                       (require 'tzc)
                       (if (org-entry-get (point) "TIMEZONE")
                           (completing-read (format "From zone (%s): "
                                                    (org-entry-get (point) "TIMEZONE"))
                                            tzc-time-zones nil nil nil nil
                                            (org-entry-get (point) "TIMEZONE"))
                         (completing-read "From zone: " tzc-time-zones nil t)))
                     (read-string "Time: ")))
  (let* ((from-offset (format-time-string "%z" (date-to-time emacsconf-date) timezone))
           (concat emacsconf-date "T" (string-pad time 5 ?0 t)  ":00.000"
    (message "%s = %s"
              "%b %d %H:%M %z"
              "%b %d %H:%M %z"

Validating schedule constraints

Once I get the availability into a standard format, I can use that to validate that sessions are scheduled during the times that speakers have indicated that they're available. So far, I've been using text like >= 10:00 EST at the beginning of the talk's AVAILABILITY property, since that's easy to parse and validate. I can use that to colour invalid talks red in an SVG, and I can make a list of invalid talks as well.

Figure 3: Validating time constraints in a draft schedule

How does that work? First, we get the time constraint out of the AVAILABILITY property with emacsconf-schedule-get-time-constraint.

(defun emacsconf-schedule-get-time-constraint (o)
  (unless (string-match "after the event" (or (plist-get o :q-and-a) ""))
    (let ((avail (or (plist-get o :availability) ""))
      (when (string-match "\\([<>]\\)=? *\\([0-9]+:[0-9]+\\) *EST" avail)
        (if (string= (match-string 1 avail) ">")
            (list (match-string 2 avail) nil)
          (list nil (match-string 2 avail)))))))

Then we can return a warning if a talk is scheduled outside those time constraints.

(defun emacsconf-schedule-check-time (label o &optional from-time to-time)
  "FROM-TIME and TO-TIME should be strings like HH:MM in EST.
Both start and end time are tested."
  (let* ((start-time (format-time-string "%H:%M" (plist-get o :start-time)))
         (end-time (format-time-string "%H:%M" (plist-get o :end-time)))
    (setq result
           (and (null o) (format "%s: Not found" label))
           (and from-time (string< start-time from-time)
                (format "%s: Starts at %s before %s" label start-time from-time))
           (and to-time (string< to-time end-time)
                (format "%s: Ends at %s after %s" label end-time to-time))))
    (when result (plist-put o :invalid result))

So then we can check all the talks as scheduled, and set the :invalid property if it's outside the availability constraints.

(defun emacsconf-schedule-validate-time-constraints (&optional info)
  (let* ((info (or info (emacsconf-get-talk-info)))
         (results (delq nil
                          (lambda (o)
                            (apply #'emacsconf-schedule-check-time
                                   (car o)
                                   (emacsconf-search-talk-info (car o) info)
                                   (cdr o)))
                          (lambda (o)
                            (let (result
                                  (constraint (emacsconf-schedule-get-time-constraint o)))
                              (when constraint
                                (setq result (apply #'emacsconf-schedule-check-time
                                                      (plist-get o :slug)
                                (when result (plist-put o :invalid result))
    (if (called-interactively-p 'any)
        (message "%s" (string-join results "\n"))

I'll cover making the schedule SVG in another blog post. It's handy to have a quick way to check availability in both text and graphical format.

Translating schedules into local times

When we e-mail speakers their schedules, we also include a translation to their local time if we know it. This is handled by emacsconf-timezone-strings, which we can use in mail templates and on wiki pages. Here's an example of how the function works:

(string-join (emacsconf-timezone-strings
              '(:scheduled "<2023-12-02 Sat 09:00-09:05>")
              '("America/Toronto" "America/Vancouver"))
Saturday, Dec 2 2023, ~9:00 AM - 9:00 AM EST (America/Toronto)
Saturday, Dec 2 2023, ~6:00 AM - 6:00 AM PST (America/Vancouver)

and here's the code for the function:

(defun emacsconf-timezone-strings (o &optional timezones)
  (mapcar (lambda (tz) (emacsconf-timezone-string o tz)) (or timezones emacsconf-timezones)))

So that's how we work with timezones in EmacsConf!

EmacsConf backstage: capturing submissions from e-mails

| emacsconf, emacs, org

2023-09-11: Updated code for recognizing fields.

People submit proposals for EmacsConf sessions via e-mail following this submission template. (You can still submit a proposal until Sept 14!) I mostly handle acceptance and scheduling, so I copy this information into our private file so that we can use it to plan the draft schedule, mail-merge speakers, and so on. I used to do this manually, but I'm experimenting with using functions to create the heading automatically so that it includes the date, talk title, and e-mail address from the e-mail, and it calculates the notification date for early acceptances as well. I use Notmuch for e-mail, so I can get the properties from (notmuch-show-get-message-properties).

Figure 1: E-mail submission

emacsconf-mail-add-submission: Add the submission from the current e-mail.
(defun emacsconf-mail-add-submission (slug)
  "Add the submission from the current e-mail."
  (interactive "MTalk ID: ")
  (let* ((props (notmuch-show-get-message-properties))
         (from (or (plist-get (plist-get props :headers) :Reply-To)
                   (plist-get (plist-get props :headers) :From)))
         (body (plist-get
                 (plist-get props :body))
         (date (format-time-string "%Y-%m-%d"
                                   (date-to-time (plist-get (plist-get props :headers) :Date))))
         (to-notify (format-time-string
                      (days-to-time emacsconf-review-days)
                      (date-to-time (plist-get (plist-get props :headers) :Date)))))
         (data (emacsconf-mail-parse-submission body)))
    (when (string-match "<\\(.*\\)>" from)
      (setq from (match-string 1 from)))
        (find-file emacsconf-org-file)
      ;;  go to the submissions entry
      (goto-char (org-find-property "CUSTOM_ID" "submissions"))
      (when (org-find-property "CUSTOM_ID" slug)
        (error "Duplicate talk ID")))
    (find-file emacsconf-org-file)
    (insert " " (or (plist-get data :title) "") "\n")
    (org-todo "TO_REVIEW")
    (org-entry-put (point) "CUSTOM_ID" slug)
    (org-entry-put (point) "SLUG" slug)
    (org-entry-put (point) "TRACK" "General")
    (org-entry-put (point) "EMAIL" from)
    (org-entry-put (point) "DATE_SUBMITTED" date)
    (org-entry-put (point) "DATE_TO_NOTIFY" to-notify)
    (when (plist-get data :time)
      (org-entry-put (point) "TIME" (plist-get data :time)))
    (when (plist-get data :availability)
      (org-entry-put (point) "AVAILABILITY"
                     (replace-regexp-in-string "\n+" " "
                                               (plist-get data :availability))))
    (when (plist-get data :public)
      (org-entry-put (point) "PUBLIC_CONTACT"
                     (replace-regexp-in-string "\n+" " "
                                               (plist-get data :public))))
    (when (plist-get data :private)
      (org-entry-put (point) "EMERGENCY"
                     (replace-regexp-in-string "\n+" " "
                                               (plist-get data :private))))
    (when (plist-get data :q-and-a)
      (org-entry-put (point) "Q_AND_A"
                     (replace-regexp-in-string "\n+" " "
                                               (plist-get data :q-and-a))))
      (insert (plist-get data :body)))
    (re-search-backward org-drawer-regexp)
    (org-fold-hide-drawer-toggle 'off)

emacsconf-mail-parse-submission: Extract data from EmacsConf 2023 submissions in BODY.
(defun emacsconf-mail-parse-submission (body)
  "Extract data from EmacsConf 2023 submissions in BODY."
  (when (listp body) (setq body (plist-get (car body) :content)))
  (let ((data (list :body body))
        (fields '((:title "^[* ]*Talk title")
                  (:description "^[* ]*Talk description")
                  (:format "^[* ]*Format")
                  (:intro "^[* ]*Introduction for you and your talk")
                  (:name "^[* ]*Speaker name")
                  (:availability "^[* ]*Speaker availability")
                  (:q-and-a "^[* ]*Preferred Q&A approach")
                  (:public "^[* ]*Public contact information")
                  (:private "^[* ]*Private emergency contact information")
                  (:release "^[* ]*Please include this speaker release"))))
      (insert body)
      (goto-char (point-min))
      ;; Try to parse it
      (while fields
        ;; skip the field title
        (when (and (or (looking-at (cadar fields))
                       (re-search-forward (cadar fields) nil t))
                   (re-search-forward "\\(:[ \t\n]+\\|\n\n\\)" nil t))
          ;; get the text between this and the next field
          (setq data (plist-put data (caar fields)
                                (buffer-substring (point)
                                                   (when (and (cdr fields)
                                                              (re-search-forward (cadr (cadr fields)) nil t))
                                                     (goto-char (match-beginning 0))
        (setq fields (cdr fields)))
      (if (string-match "[0-9]+" (or (plist-get data :format) ""))
          (plist-put data :time (match-string 0 (or (plist-get data :format) ""))))

The functions above are in the emacsconf-el repository. When I call emacsconf-mail-parse-submission and give it the talk ID I want to use, it makes the Org entry.

Figure 2: Creating the entry

We store structured data in Org Mode properties such as NAME, EMAIL and EMERGENCY. I tend to make mistakes when typing, so I have a short function that sets an Org property based on a region. This is the code from my personal config:

my-org-set-property: In the current entry, set PROPERTY to VALUE.
(defun my-org-set-property (property value)
  "In the current entry, set PROPERTY to VALUE.
Use the region if active."
  (interactive (list (org-read-property-name)
                     (when (region-active-p) (replace-regexp-in-string "[ \n\t]+" " " (buffer-substring (point) (mark))))))
  (org-set-property property value))

I've bound it to C-c C-x p. This is what it looks like when I use it:

Figure 3: Setting Org properties from the region

That helps me reduce errors in entering data. I sometimes forget details, so I ask other people to double-check my work, especially when it comes to speaker availability. That's how I copy the submission e-mails into our Org file.