wip: feat: Defer many packages

Shaving MILLISECONDS off our startup time!!!  Fuck yes!

I've measured the average startup time to be 0.68s in the previous commit, and an average of 0.52 with this commit.

README.org

@@ -95,6 +95,35 @@ On boot, ...
 
 sydnix-cli is a command-line utility written in Clojure wrapping various sydnix-related scripts.
 
+** Deferring Emacs packages
+
+Nearly all configuration of Emacs packages happens under the ~use-package~ macro. ~use-package~ has various keywords with special syntax for common tasks, such as instrumenting hooks, setting keybindings, and customising variables. You may be surprised to learn that these are not /just/ syntactic sugar }:) (I was).
+
+As an example, this
+
+#+begin_src emacs-lisp
+(use-package which-key
+  :hook (on-first-input . which-key-mode)
+  :custom
+  (which-key-allow-evil-operators t)
+  (which-key-show-operator-state-maps t)
+#+end_src
+
+is not the same as this
+
+#+begin_src emacs-lisp
+(use-package which-key
+  :config
+  (add-hook 'on-first-input #'which-key-mode)
+  (setq which-key-allow-evil-operators t)
+  (setq which-key-show-operator-state-maps t)
+#+end_src
+
+The difference connects to another silly obsession of the Emacs hacker: startup time. ~use-package~'s special keywords will /defer/ the loading of the package ([cite:@systemcrafters2021how]) . E.g., instead of loading ~which-key~ on startup, it will be loaded when the ~on-first-input~ hook is first called.
+
+~on-first-input~ is one of many useful hooks provided by the package [[https://github.com/emacsmirror/on][on.el]] specialised for fine-grained control of package loading.
+
+>>>>>>> Conflict 1 of 1 ends
 * Tasks
 
 ** Begin setting up doomless Emacs

users/crumb/programs/emacs/init-straight.el

@@ -13,6 +13,7 @@
                            "straight/repos/straight.el/bootstrap.el"))
         (bootstrap-version 7))
     (unless (file-exists-p bootstrap-file)
+      (message "Could not find Straight's bootstrap file.  Attempting to download it now.")
       (let* ((url "https://raw.githubusercontent.com/radian-software/straight.el/develop/install.el")
              (url-buffer (url-retrieve-synchronously
                           url 'silent 'inhibit-cookies)))

users/crumb/programs/emacs/init.el

@@ -11,6 +11,7 @@
 (add-to-list 'load-path (file-name-concat user-emacs-directory "modules"))
 (add-to-list 'load-path (file-name-concat user-emacs-directory "lib"))
 
+(require 'syd-autosave)
+(require 'syd-display-startup-time)
 (require 'syd-evil)
 (require 'syd-ui)
-(require 'syd-autosave)

users/crumb/programs/emacs/lib/syd-prelude.el

@@ -11,4 +11,9 @@
   (or (getenv "EMACS_CACHE_DIR")
       (error "Need $EMACS_CACHE_DIR")))
 
+;; `on.el' provies a collection of utility hooks and functions ported from Doom
+;; Emacs.  The hooks make it easier to speed up Emacs startup by providing
+;; finer-grained control of the timing at which packages are loaded.
+(use-package on)
+
 (provide 'syd-prelude)

users/crumb/programs/emacs/modules/syd-autosave.el

@@ -19,21 +19,18 @@
           (".*"
            ,(file-name-concat syd-cache-dir "autosave") t))
         kept-new-versions 5
-        delete-old-versions t
-        save-place-file (file-name-concat syd-cache-dir "places")
-        bookmark-default-file (file-name-concat syd-data-dir "bookmarks")
-        recentf-save-file (file-name-concat syd-data-dir "recentf")))
+        delete-old-versions t))
 
 ;; Save your cursor position in recently-opened files.
 (use-package saveplace
-  :config
-  (save-place-mode 1))
+  :hook (on-first-file . save-place-mode)
+  :custom (save-place-file (file-name-concat syd-cache-dir "places")))
 
 ;; Keep track of recently-visited files.
 (use-package recentf
-  :config
-  (add-hook 'find-file-hook #'recentf-save-list)
-  (recentf-mode 1))
+  :hook ((on-first-file . recentf-mode)
+         (find-file-hook . recentf-save-list))
+  :custom (recentf-save-file (file-name-concat syd-data-dir "recentf")))
 
 
 (provide 'syd-autosave)

users/crumb/programs/emacs/modules/syd-display-startup-time.el

@@ -0,0 +1,14 @@
+;;; syd-display-startup-time.el -*- lexical-binding: t; -*-
+
+(defun syd-display-startup-time ()
+  (message "Emacs loaded in %s with %d garbage collections."
+           (format "%.3f seconds"
+                   (float-time
+                    (time-subtract after-init-time before-init-time)))
+           gcs-done))
+
+(use-package emacs
+  :hook
+  (emacs-startup-hook . syd-display-startup-time))
+
+(provide 'syd-display-startup-time)

users/crumb/programs/emacs/modules/syd-evil.el

@@ -2,10 +2,26 @@
 
 ;; Vim emulation.
 (use-package evil
-  :init
-  (setq evil-want-minibuffer t)
-  (setq evil-move-beyond-eol t)
-  (setq evil-vsplit-window-right t)
+  :preface
+  (setq evil-want-minibuffer t
+        evil-move-beyond-eol t
+        evil-vsplit-window-right t
+        evil-ex-search-vim-style-regexp t
+        evil-ex-visual-char-range t
+        evil-mode-line-format nil
+        evil-normal-state-cursor 'box
+        evil-emacs-state-cursor 'hbar
+        evil-operator-state-cursor 'evil-half-cursor
+        evil-insert-state-cursor 'bar
+        evil-visual-state-cursor 'hollow
+        ;; Only do highlighting in selected window so that Emacs has less work
+        ;; to do highlighting them all.
+        evil-ex-interactive-search-highlight 'selected-window
+        ;; It's infuriating that innocuous "beginning of line" or "end of line"
+        ;; errors will abort macros, so suppress them:
+        evil-kbd-macro-suppress-motion-error t
+        evil-undo-system (cond ((featurep 'undo-tree) 'undo-tree)
+                               ((featurep 'undo-fu) 'undo-fu)))
   ;; These two are required for evil-collection.
   (setq evil-want-keybinding nil
         evil-want-integration t)
@@ -20,16 +36,18 @@
 ;; integrations.
 (use-package evil-collection
   :after evil
-  :custom
-  (evil-collection-setup-minibuffer t)
+  :custom (evil-collection-setup-minibuffer t)
   :config
   (evil-collection-init))
 
 ;; Tim Pope's famous `surround.vim' for Evil.
 (use-package evil-surround
-  :ensure t
+  :commands (global-evil-surround-mode
+             evil-surround-edit
+             evil-Surround-edit
+             evil-surround-region)
+  :hook (on-first-input . global-evil-surround-mode)
   :config
-  (global-evil-surround-mode 1)
   ;; In `emacs-lisp-mode', `' is a much more common pair than ``.
   (add-hook 'emacs-lisp-mode-hook
             (lambda ()
@@ -38,20 +56,21 @@
 ;; TODO: I'd like JK to escape visual state.  evil-escape only allows defining a
 ;; single key sequence.  Perhaps key-chord is capable of this?
 (use-package evil-escape
-  :config
-  (setq-default evil-escape-key-sequence "jk"
-                evil-escape-delay 0.15)
-  (evil-escape-mode 1))
+  :hook (on-first-input . evil-escape-mode)
+  :custom ((evil-escape-key-sequence "jk")
+           (evil-escape-delay 0.15)))
 
 ;; `evil-nerd-commenter' has a bunch of cool functions[1].  Here, only the Evil
 ;; operator is used. }:3
 ;; [1]: https://github.com/redguardtoo/evil-nerd-commenter?tab=readme-ov-file#commands-and-hotkeys
 (use-package evil-nerd-commenter
-  :config
-  (define-key evil-normal-state-map "#" #'evilnc-comment-operator)
-  (define-key evil-visual-state-map "#" #'evilnc-comment-operator)
-  (define-key evil-inner-text-objects-map "c" 'evilnc-inner-commenter)
-  (define-key evil-outer-text-objects-map "c" 'evilnc-outer-commenter))
+  :commands (evilnc-comment-operator
+             evilnc-inner-comment
+             evilnc-outer-commenter)
+  :bind (:map evil-normal-state-map ("#" . evilnc-comment-operator)
+         :map evil-visual-state-map ("#" . evilnc-comment-operator)
+         :map evil-inner-text-objects-map ("c" . evilnc-inner-comment)
+         :map evil-outer-text-objects-map ("c" . evilnc-outer-comment)))
 
 ;; Enhance `evil-surround' with integration with `embrace'.
 (use-package evil-embrace
@@ -60,68 +79,60 @@
   :config
   (evil-embrace-enable-evil-surround-integration))
 
-;; Provides a command to swap two regions of text.
+;; Provides an Evil operator to swap two spans of text.
 (use-package evil-exchange
-  :config
-  (define-key evil-normal-state-map "gX" 'evil-exchange)
-  (define-key evil-visual-state-map "gX" 'evil-exchange))
+  :bind (:map evil-normal-state-map ("gX" . evil-exchange)
+         :map evil-visual-state-map ("gX" . evil-exchange)))
 
 ;; Evil doesn't ship with support for Vim's 'g-'/'g+'.  `evil-numbers'
 ;; implements this.
 (use-package evil-numbers
-  :config
   ;; 'g=' is a bit more comfortable than 'g+', whilst preserving the analogy.
   ;; ('=' is '+' modulo shift)
-  (define-key evil-normal-state-map "g=" 'evil-numbers/inc-at-pt)
-  (define-key evil-normal-state-map "g-" 'evil-numbers/dec-at-pt))
+  :bind (:map evil-normal-state-map ("g=" . 'evil-numbers/inc-at-pt)
+         :map evil-normal-state-map ("g-" . 'evil-numbers/dec-at-pt)))
 
 ;; Tree-sitter queries → Evil text objects.
-(use-package evil-textobj-tree-sitter)
+(use-package evil-textobj-tree-sitter
+  :defer t)
 
 ;; Visually "flash" the region acted upon by Evil-mode operations.
 (use-package evil-goggles
+  :hook (on-first-input . evil-goggles-mode)
   ;; The flash animation will delay actions, which can be very annoying for some
   ;; operations.  Disable `evil-goggles' for those ones.
   :custom
-  (evil-goggles-enable-delete nil)
+  ((evil-goggles-enable-delete nil)
    (evil-goggles-enable-change nil)
-  (evil-goggles-duration 0.1)
-  :config
-  (evil-goggles-mode 1))
+   (evil-goggles-duration 0.1)))
 
 ;; Change cursor shape and color by evil state in terminal.
 (use-package evil-terminal-cursor-changer
+  ;; This package is only useful in the terminal.
   :if (not (display-graphic-p))
-  :config
-  (setq evil-motion-state-cursor 'box)
-  (setq evil-visual-state-cursor 'box)
-  (setq evil-normal-state-cursor 'box)
-  (setq evil-insert-state-cursor 'bar)
-  (setq evil-emacs-state-cursor 'hbar)
-  (evil-terminal-cursor-changer-activate))
+  :hook (on-first-input . evil-terminal-cursor-changer-activate))
 
 ;; Automatic alignment in region, by regexp.
 (use-package evil-lion
-  :config
-  (evil-lion-mode 1))
+  :hook (on-first-input . evil-lion-mode))
 
-;; Provides the 'g' text object which selects the entire buffer.
-(use-package evil-textobj-entire)
+;; 'g' text object selecting the entire buffer.
+(with-eval-after-load 'evil
+  (evil-define-text-object
+    evil-entire-buffer (count &optional beg end type)
+    "Select entire buffer"
+    (evil-range (point-min) (point-max) type))
+  (define-key evil-inner-text-objects-map "g" #'evil-entire-buffer)
+  (define-key evil-outer-text-objects-map "g" #'evil-entire-buffer))
 
 ;; 2-character search.
 (use-package evil-snipe
-  :commands evil-snipe-local-mode evil-snipe-override-local-mode
-  :hook (on-first-input . evil-snipe-override-mode)
-  :hook (on-first-input . evil-snipe-mode)
-  :init
-  (setq evil-snipe-smart-case t
-        evil-snipe-scope 'visible
-        evil-snipe-repeat-scope 'visible
-        evil-snipe-char-fold t))
-
-;; Extend the set of delimiters recognised by '%'.
-(use-package evil-matchit
-  :config
-  (global-evil-matchit-mode 1))
+  :commands (evil-snipe-local-mode evil-snipe-override-local-mode)
+  :hook ((on-first-input . evil-snipe-override-mode)
+         (on-first-input . evil-snipe-mode))
+  :custom ((evil-snipe-smart-case t)
+           (evil-snipe-scope 'visible)
+           (evil-snipe-repeat-scope 'visible)
+           (evil-snipe-char-fold t)))
 
 (provide 'syd-evil)

users/crumb/programs/emacs/modules/syd-ui.el

@@ -2,11 +2,9 @@
 
 ;; Show possible completions for a partially-entered key sequence.
 (use-package which-key
-  :custom
-  (which-key-allow-evil-operators t)
-  (which-key-show-operator-state-maps t)
-  :config
-  (which-key-mode 1))
+  :hook (on-first-input . which-key-mode)
+  :custom ((which-key-allow-evil-operators t)
+           (which-key-show-operator-state-maps t)))
 
 ;; Beautiful theme in dark and light.
 (use-package kanagawa-themes
@@ -16,17 +14,20 @@
 (use-package emacs
   :custom
   ;; Allow the opening of new minibuffers from inside existing minibuffers.
-  (enable-recursive-minibuffers t)
+  ((enable-recursive-minibuffers t)
    ;; Hide commands in M-x which do not work in the current mode.
-  (read-extended-command-predicate #'command-completion-default-include-p)
+   (read-extended-command-predicate #'command-completion-default-include-p))
   :config
-  ;; Disable blinking cursor.  I don't really like it, but it also doesn't play
-  ;; well with `evil-terminal-cursor-changer'.
+  ;; Disable blinking cursor.  Aesthetically, I personally don't fancy it;
+  ;; technically, it doesn't play well with `evil-terminal-cursor-changer'.
   (blink-cursor-mode -1))
 
+;; Vertico is a simple completion engine that replaces Emacs' built-in
+;; completion engine, achieving Just Works™ compatibility.  This is in contrast
+;; to e.g. Helm and Ivy, which spawn ecosystems orthogonal to Emacs, and
+;; diametrically-opposed to each other.
 (use-package vertico
-  :init
-  (vertico-mode 1))
+  :hook (on-first-input . vertico-mode))
 
 ;; Orderless provides a completion style that divides the pattern into
 ;; space-separated components, and matches candidates that match all of the
@@ -34,8 +35,8 @@
 ;; ways: literally, as a regexp, as an initialism, in the flex style, or as
 ;; multiple word prefixes.  By default, regexp and literal matches are enabled.
 (use-package orderless
-  :custom
-  (completion-styles '(orderless basic))
-  (completion-category-overrides '((file (styles basic partial-completion)))))
+  :custom ((completion-styles '(orderless basic))
+           (completion-category-overrides
+            '((file (styles basic partial-completion))))))
 
 (provide 'syd-ui)