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emacs/config/completion.org
2025-10-30 14:34:57 -05:00

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Modern Completion Stack

I'm using modern to mean current, and as the colloquial usage given by the community at large. At least based on my observations anyway. Most of these serve to bolster the existing facilities of emacs rather than replace them.

Prescient

Prescient provides sorting for completion candidates; So recently used, and frequent selections come first.

(use-package prescient
  :defer t
  :config
  (prescient-persist-mode))

(use-package corfu-prescient
  :after (corfu prescient)
  :config (corfu-prescient-mode))

(use-package vertico-prescient
  :after (prescient vertico))

Corfu

Corfu provides completion within buffers from various sources. Though it doesn't provide much in the way of sources itself. It works in conjunction with the other packages in this section to provide it with candidates.

(use-package corfu
  :custom
  (corfu-auto t)               ;; Enable auto completion
  (corfu-preselect 'directory) ;; Select the first candidate, except for directories

  :init
  (global-corfu-mode)
  (corfu-popupinfo-mode) ;; Show docs next to candidates.

  :config
  ;; Free the RET key for less intrusive behavior.
  ;; Option 1: Unbind RET completely
  ;; (keymap-unset corfu-map "RET")
  ;; Option 2: Use RET only in shell modes
  (keymap-set corfu-map "RET" `( menu-item "" nil :filter
                                 ,(lambda (&optional _)
                                    (and (derived-mode-p 'eshell-mode 'comint-mode)
                                         #'corfu-send)))))

Cape

The Cape package (Completion At Point Extensions) provides access to Corfu to various backends. Things like file completions and simple buffer completion are examples of good backends to add here. Other backends are listed here.

(use-package cape
  :bind ("M-<tab>" . cape-prefix-map)
  :init
  (add-hook 'completion-at-point-functions #'cape-dabbrev)
  (add-hook 'completion-at-point-functions #'cape-file)
  (add-hook 'completion-at-point-functions #'cape-elisp-block))

Orderless

This provides numerous flexible methods for matching completion candidates. Rather than just matching strings exactly it can also match portions, or a custom regular expression, and more.

Link

(use-package orderless
  :ensure t
  :custom
  (completion-styles '(orderless basic))
  (completion-category-defaults nil)
  (completion-category-overrides '((file (styles partial-completion)))))

Vertico

Vertico is one of the best minibuffer improvement packages out there. Combined with the other packages in this section it makes minibuffer completions concise, and descriptive.

(use-package vertico
  :demand t
  :custom (vertico-cycle t)
  :config
  (setf (car vertico-multiline) "\n") ;; don't replace newlines
  (vertico-mode)
  (vertico-prescient-mode)
  (define-key vertico-map (kbd "C-h") #'+minibuffer-up-dir))

Marginalia

Marginalia adds completion annotations on the right side of the minibuffer.

(use-package marginalia
  :defer 2
  :config (marginalia-mode)
  (setf (alist-get 'elpaca-info marginalia-command-categories) 'elpaca))

Consult

Consult provides search and navigation commands based on the emacs completion function completing-read.

Think about this as a tightly integrate search that can tie into many aspects of a project, and convey the results to various completion facilities.

(use-package consult
  :ensure t
  :bind (;; C-c bindings in `mode-specific-map'
         ("C-c M-x" . consult-mode-command)
         ("C-c h" . consult-history)
         ("C-c k" . consult-kmacro)
         ("C-c m" . consult-man)
         ("C-c i" . consult-info)
         ([remap Info-search] . consult-info)
         ;; C-x bindings in `ctl-x-map'
         ("C-x M-:" . consult-complex-command)     ;; orig. repeat-complex-command
         ("C-x b" . consult-buffer)                ;; orig. switch-to-buffer
         ("C-x 4 b" . consult-buffer-other-window) ;; orig. switch-to-buffer-other-window
         ("C-x 5 b" . consult-buffer-other-frame)  ;; orig. switch-to-buffer-other-frame
         ("C-x t b" . consult-buffer-other-tab)    ;; orig. switch-to-buffer-other-tab
         ("C-x r b" . consult-bookmark)            ;; orig. bookmark-jump
         ("C-x p b" . consult-project-buffer)      ;; orig. project-switch-to-buffer
         ;; Custom M-# bindings for fast register access
         ("M-#" . consult-register-load)
         ("M-'" . consult-register-store)          ;; orig. abbrev-prefix-mark (unrelated)
         ("C-M-#" . consult-register)
         ;; Other custom bindings
         ("M-y" . consult-yank-pop)                ;; orig. yank-pop
         ;; M-g bindings in `goto-map'
         ("M-g e" . consult-compile-error)
         ("M-g f" . consult-flymake)               ;; Alternative: consult-flycheck
         ("M-g g" . consult-goto-line)             ;; orig. goto-line
         ("M-g M-g" . consult-goto-line)           ;; orig. goto-line
         ("M-g o" . consult-outline)               ;; Alternative: consult-org-heading
         ("M-g m" . consult-mark)
         ("M-g k" . consult-global-mark)
         ("M-g i" . consult-imenu)
         ("M-g I" . consult-imenu-multi)
         ;; M-s bindings in `search-map'
         ("M-s d" . consult-find)                  ;; Alternative: consult-fd
         ("M-s c" . consult-locate)
         ("M-s g" . consult-grep)
         ("M-s G" . consult-git-grep)
         ("M-s r" . consult-ripgrep)
         ("M-s l" . consult-line)
         ("M-s L" . consult-line-multi)
         ("M-s k" . consult-keep-lines)
         ("M-s u" . consult-focus-lines)
         ;; Isearch integration
         ("M-s e" . consult-isearch-history)
         :map isearch-mode-map
         ("M-e" . consult-isearch-history)         ;; orig. isearch-edit-string
         ("M-s e" . consult-isearch-history)       ;; orig. isearch-edit-string
         ("M-s l" . consult-line)                  ;; needed by consult-line to detect isearch
         ("M-s L" . consult-line-multi)            ;; needed by consult-line to detect isearch
         ;; Minibuffer history
         :map minibuffer-local-map
         ("M-s" . consult-history)                 ;; orig. next-matching-history-element
         ("M-r" . consult-history))                ;; orig. previous-matching-history-element

  ;; Enable automatic preview at point in the *Completions* buffer. This is
  ;; relevant when you use the default completion UI.
  :hook (completion-list-mode . consult-preview-at-point-mode)

  ;; The :init configuration is always executed (Not lazy)
  :init

  ;; Tweak the register preview for `consult-register-load',
  ;; `consult-register-store' and the built-in commands.  This improves the
  ;; register formatting, adds thin separator lines, register sorting and hides
  ;; the window mode line.
  (advice-add #'register-preview :override #'consult-register-window)  (setq register-preview-delay 0.5)

  ;; Use Consult to select xref locations with preview
  (setq xref-show-xrefs-function #'consult-xref
        xref-show-definitions-function #'consult-xref)

  ;; Configure other variables and modes in the :config section,
  ;; after lazily loading the package.
  :config

  ;; Optionally configure preview. The default value
  ;; is 'any, such that any key triggers the preview.
  ;; (setq consult-preview-key 'any)
  ;; (setq consult-preview-key "M-.")
  ;; (setq consult-preview-key '("S-<down>" "S-<up>"))
  ;; For some commands and buffer sources it is useful to configure the
  ;; :preview-key on a per-command basis using the `consult-customize' macro.
  (consult-customize
   consult-theme :preview-key '(:debounce 0.2 any)
   consult-ripgrep consult-git-grep consult-grep consult-man
   consult-bookmark consult-recent-file consult-xref
   consult--source-bookmark consult--source-file-register
   consult--source-recent-file consult--source-project-recent-file
   ;; :preview-key "M-."
   :preview-key '(:debounce 0.4 any))

  ;; Optionally configure the narrowing key.
  ;; Both < and C-+ work reasonably well.
  (setq consult-narrow-key "<") ;; "C-+"

  ;; Optionally make narrowing help available in the minibuffer.
  ;; You may want to use `embark-prefix-help-command' or which-key instead.
  ;; (keymap-set consult-narrow-map (concat consult-narrow-key " ?") #'consult-narrow-help)
  )