Tweak Script-Fu config a little

I don't use these anymore, instead I hand-write stuff on my e-ink
tablet like the techno-contrarian qípā that I am.

config.org

@@ -2,6 +2,17 @@
 #+AUTHOR: Camden Dixie O'Brien
 #+ATTR_LATEX: :float t
 
+* Prelude
+  Before doing anything else, set a higher [[help:gc-cons-threshold][gc-cons-threshold]] (I'm
+  using 100 MiB here) so that we're not garbage collecting during
+  initialisation to make startup a little faster.  We'll save the
+  original value to restore it at the end of initialisation.
+
+  #+begin_src emacs-lisp
+    (setq original-gc-cons-threshold gc-cons-threshold)
+    (setq gc-cons-threshold (* 100 1024 1024))
+  #+end_src
+
 * Customize
   Hey, customize, leave my ~/.emacs.d/init.el alone!
 
@@ -222,35 +233,6 @@
      (yas-reload-all)
    #+end_src
 
-* Calendar / Diary
-  Weeks start on Sunday by default, this can be changed to start on
-  Monday by setting [[help:calendar-week-start-day][calendar-week-start-day]] to 1:
-
-  #+begin_src emacs-lisp
-    (setq calendar-week-start-day 1)
-  #+end_src
-
-  Set latitute, longitude and location name to Bristol to get sunrise
-  and sunset times:
-
-  #+begin_src emacs-lisp
-    (setq calendar-latitude 51.45)
-    (setq calendar-longitude -2.58)
-    (setq calendar-location-name "Bristol, UK")
-  #+end_src
-
-  Emacs needs to be told where the diary file is, of course:
-
-  #+begin_src emacs-lisp
-    (setq diary-file "~/Documents/diary")
-  #+end_src
-
-  I want to use ISO-style dates in there:
-
-  #+begin_src emacs-lisp
-    (calendar-set-date-style 'iso)
-  #+end_src
-
 * Org
 ** Code and Quote block shortcuts
    I am a big fan of using =<s= for source blocks and =<q= for quotes;
@@ -282,91 +264,6 @@
                              'org-insert-heading-after-current)))
    #+end_src
 
-** Journal Files
-   Sometimes I like to make a todo list for a day if I've a lot to do,
-   or write a little bit about a day if it's been particularly
-   eventful. In both of these cases, it would be nice to just be able
-   to hit a particular keybinding and have the right buffer pop up. I
-   was using =org-roam='s daily notes feature for this, but I ended up
-   getting annoyed with =org-roam= (too many features for my taste
-   lol).
-
-   The convention I'm going for is for is having a particular
-   directory for these journal entries and then give each file a name
-   like "2022-10-30.org". With that in mind, there are two obvious
-   variables to define:
-
-   #+begin_src emacs-lisp
-     (defvar journal-directory
-       "~/Documents/org/journal"
-       "Directory to store journal entries in.")
-
-     (defvar journal-filename-format
-       "%F"
-       "Date format to use for journal entries' filenames (not including
-     the \".org\" extension)")
-   #+end_src
-
-   I can't be bothered to handle [[help:journal-directory][journal-directory]] not existing in the
-   main code, so I'm just going to make sure it exists here. The
-   second argument to [[help:make-directory][make-directory]] specifies to create parent
-   directories too if necessary.
-
-   #+begin_src emacs-lisp
-     (unless (file-directory-p journal-directory)
-       (make-directory journal-directory t))
-   #+end_src
-
-   The next step is to define a function to determine the filename for
-   today's journal entry. This is fairly straightforward, using
-   [[help:format-time-string][format-time-string]] to get the current date in the right format,
-   then sticking that together with the directory, extension, etc.
-
-   #+begin_src emacs-lisp
-     (defun journal-entry-filename ()
-       "Returns the filename for today's journal entry."
-       (let ((date-string (format-time-string journal-filename-format)))
-         (concat journal-directory "/" date-string ".org")))
-   #+end_src
-
-   If the journal entry doesn't exist yet, I want it to be populated
-   with the long-form date as the title:
-
-   #+begin_src emacs-lisp
-     (defvar journal-title-date-format
-       "%A, %-e %B %+4Y"
-       "The date format to use for journal entries' titles.")
-
-     (defun insert-default-journal-entry-contents ()
-       "Insert the default journal entry contents (currently this is
-     just today's long-form date as a title) into the current buffer."
-       (insert "#+TITLE: "
-               (format-time-string journal-title-date-format)
-               "\n\n"))
-   #+end_src
-
-   We can now make a function to open today's journal entry fairly
-   trivially using [[help:find-file][find-file]], and the above utilities. It should be
-   interactive, as this is what we'll be calling in the key binding.
-
-   #+begin_src emacs-lisp
-     (defun open-journal-entry ()
-       "Opens today's journal entry, populating it with the default
-     contents if it does not already exist."
-       (interactive)
-       (let* ((filename (journal-entry-filename))
-              (new-entry (not (file-exists-p filename))))
-         (find-file filename)
-         (when new-entry
-           (insert-default-journal-entry-contents))))
-   #+end_src
-
-   Finally, [[help:open-journal-entry][open-journal-entry]] can be bound to a key:
-
-   #+begin_src emacs-lisp
-     (global-set-key (kbd "C-c t") 'open-journal-entry)
-   #+end_src
-
 ** Source Blocks
    Pressing tab inside a source block should indent appropriately for its
    language.
@@ -494,116 +391,7 @@
              (auto-mode . emacs)))
    #+end_src
 
-** Workflow States
+** Indentation
-   I like to have =IN-PROGRESS= and =CANCELLED= workflow states as
-   well as the standard =TODO= and =DONE=. Cancelled items also want a
-   note attached explaining why. All this can be added by setting
-   [[help:org-todo-keywords][org-todo-keywords]]:
-
-   #+begin_src emacs-lisp
-     (setq org-todo-keywords
-           '((sequence "TODO" "IN-PROGRESS" "|" "DONE" "CANCELLED(@)")))
-   #+end_src
-
-   The ="|"= separates /needs further action/ states (before it) from
-   /no further action needed/ states (after it).
-
-   I also want to log the date and time when a note is marked as done:
-
-   #+begin_src emacs-lisp
-     (setq org-log-done 'time)
-   #+end_src
-
-** Agenda
-   Time to try org-mode's agenda feature again I think. Last time I
-   didn't end up using it much, but I am /much/ more of an Emacs
-   addict now so I do forsee it actually surviving (this will be funny
-   to read in the future if not).
-
-   I want to show all TODOs in =.org= files under my top-level
-   =~/Documents/org= directory and any in this config itself. This is
-   done by enumerating all files under =~/Documents/org= with
-   [[help:directory-files-recursively][directory-files-recursively]], then setting [[help:org-agenda-files][org-agenda-files]] to this,
-   along with this config's path.
-
-   #+begin_src emacs-lisp
-     (let ((org-docs
-            (directory-files-recursively "~/Documents/org" ".+\.org$")))
-       (setq org-agenda-files `("~/.emacs.d/config.org" ,@org-docs)))
-   #+end_src
-
-   Also I find it really very annoying that the the current window
-   layout is destroyed when you run =org-agenda=. That behaviour is
-   changed by setting [[help:org-agenda-window-setup][org-agenda-window-setup]]:
-
-   #+begin_src emacs-lisp
-     (setq org-agenda-window-setup 'current-window)
-   #+end_src
-
-   Include events from my diary:
-
-   #+begin_src emacs-lisp
-     (setq org-agenda-include-diary t)
-   #+end_src
-
-   Though I don't like the time grid being on by default.
-
-   #+begin_src emacs-lisp
-     (setq org-agenda-use-time-grid nil)
-   #+end_src
-
-   I primarily use the TODO list to keep track of un-scheduled tasks,
-   so I don't want those displayed in there:
-
-   #+begin_src emacs-lisp
-     (setq org-agenda-todo-ignore-scheduled t)
-   #+end_src
-
-   Finally, I want a keybinding for the weekly agenda and global TODO
-   list agenda view:
-
-   #+begin_src emacs-lisp
-     (defun org-weekly-agenda-and-todo-list ()
-       (interactive)
-       (org-agenda nil "n"))
-
-     (global-set-key (kbd "C-c a") 'org-weekly-agenda-and-todo-list)
-   #+end_src
-
-** Habits
-   Habit tracking requires the habits org module to be loaded. This is
-   done by adding the symbol ~'habits~ to [[help:org-modules][org-modules]], if it's not in
-   there already. I originally didn't have the surrounding ~unless~,
-   but it causes problems when re-loading the config using
-   [[help:org-babel-load-file][org-babel-load-file]].
-
-   #+begin_src emacs-lisp
-     (unless (member 'habits org-modules)
-       (add-to-list 'org-modules 'org-habit)
-       (org-load-modules-maybe t))
-   #+end_src
-
-   The [[help:org-load-modules-maybe][org-load-modules-maybe]] call forces org to load the modules in
-   [[help:org-modules][org-modules]]. Not sure it's needed, but I ran into some weird issues
-   and I think it fixed them.
-
-   The consistency graph is very nice but overlaps a lot of the habit
-   names, so I want to move it to the right a little:
-
-   #+begin_src emacs-lisp
-     (setq org-habit-graph-column 42)
-   #+end_src
-
-   Also it displays days that you did a habit in red if the habit was
-   overdue on that day, which makes a sort of sense, but always
-   showing days you did things in green makes more sense to me. The
-   variable [[help:org-habit-show-done-always-green][org-habit-show-done-always-green]] controls this.
-
-   #+begin_src emacs-lisp
-     (setq org-habit-show-done-always-green t)
-   #+end_src
-
-** Identation
    Setting [[help:org-adapt-indentation][org-adapt-indentation]] to ~t~ ensures that Org will indent text
    under a headline:
 
@@ -1397,7 +1185,7 @@
      (setq Man-notify-method 'pushy)
    #+end_src
 
-** Script-Fu Mode
+** Script-Fu
    GIMP has a scheme-based language -- Script-Fu -- built into it that
    you can use to script things (based).  Sadly, the built-in console
    is rather lackluster as a coding environment.  Happily, there /is/
@@ -1407,12 +1195,12 @@
 
    It's things like this that make me really glad I switched to Emacs
    because this is ridiculously cool.  By my definition of "cool"
-   anyway -- what can I say, I'm a massive nerd.
+   anyway (what can I say, I'm a massive nerd).
 
    I should probably extract this and make a standalone package out of
    it and stick it on Melpa at some point.
 
-*** REPL Mode
+*** REPL
     The Script-Fu server request format is very simple:
 
     | Bytes | Description                                   |
@@ -1467,7 +1255,7 @@
 
     The response format is similarly simple:
 
-    | Bytes | Content                                 |
+    | Bytes | Description                             |
     |-------+-----------------------------------------|
     |     0 | 'G' magic byte (47h)                    |
     |     1 | Status code -- 0 on success, 1 on error |
@@ -1524,8 +1312,8 @@
         (interactive)
         (let ((buffer (get-buffer-create "*Script-Fu REPL*")))
           (when (not (comint-check-proc buffer))
-            (make-comint-in-buffer "Script-Fu REPL" buffer
+            (make-comint-in-buffer "Script-Fu REPL"
-                                   script-fu-repl-server)
+                                   buffer script-fu-repl-server)
             (with-current-buffer buffer (script-fu-repl-mode)))
           (pop-to-buffer buffer '((display-buffer-in-direction)
                                   (direction . below)
@@ -1533,7 +1321,7 @@
           buffer))
     #+end_src
 
-*** Code Editing Mode
+*** Code Editing
     With the client stuff done, we can define the code editing mode:
 
     #+begin_src emacs-lisp
@@ -1541,7 +1329,9 @@
     #+end_src
 
     Now to define something to send an expression or region to the
-    REPL:
+    REPL.  Since =script-fu-repl= returns the buffer we can use that
+    to transparently start a REPL or get the existing one if one's
+    already running.
 
     #+begin_src emacs-lisp
       (defun script-fu-mode-send-region-or-sexp ()
@@ -1552,21 +1342,19 @@
                           (buffer-substring-no-properties start end))
                       (thing-at-point 'sexp t))))
           (if (not code) (message "No code to send.")
-            (let* ((repl-buffer (script-fu-repl))
+            (let* ((repl-proc (get-buffer-process (script-fu-repl))))
-                   (repl-proc (get-buffer-process repl-buffer)))
               (script-fu-repl-send repl-proc code)))))
 
       (define-key script-fu-mode-map (kbd "C-c C-c")
                   'script-fu-mode-send-region-or-sexp)
     #+end_src
 
-    And finally a similar thing for the whole file:
+    And finally, a similar thing for the whole file:
 
     #+begin_src emacs-lisp
       (defun script-fu-mode-send-file ()
         (interactive)
-        (let* ((repl-buffer (script-fu-repl))
+        (let* ((repl-proc (get-buffer-process (script-fu-repl)))
-               (repl-proc (get-buffer-process repl-buffer))
                (buffer-contents
                 (buffer-substring-no-properties (point-min)
                                                 (point-max))))
@@ -1667,12 +1455,10 @@
      (setq god-exempt-predicates nil)
    #+end_src
 
-* Fin
+* Coda
-  Now that start-up is finished, [[help:gc-cons-threshold][gc-cons-threshold]] and
+  Now that initialization is finished, [[help:gc-cons-threshold][gc-cons-threshold]] should be set
-  [[help:gc-cons-percentage][gc-cons-percentage]] need to be set back to reasonable values to avoid
+  back to its default value:
-  memory usage getting too high.
 
   #+begin_src emacs-lisp
-    (setq gc-cons-threshold 1000000)
+    (setq gc-cons-threshold original-gc-cons-threshold)
-    (setq gc-cons-percentage 0.2)
   #+end_src