dotfiles/emacs-lisp/tempel.org

Tempel

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Tempel is a tiny template package for Emacs, which uses the syntax of the Emacs Tempo library. Tempo is an ancient temple of the church of Emacs. It is 27 years old, but still in good shape since it successfully resisted change over the decades. However it may look a bit dusty here and there. Therefore we present to you, Tempel, a modernized implementation of Tempo, in the form of three commands.

  (use-package tempel
    :straight '(tempel :type git :host github :repo "minad/tempel")
    :config
    <<tempel-path>>
    :init
    <<tempel-hooks>>
    <<tempel-keymaps>>)

Set the template file to the result of tangling Tempel - Templates.

  (setq tempel-path (expand-file-name "~/roam/emacs-lisp/templates.lisp"))

Hook tempel-capf on both prog-mode and text-mode.

  (defun tempel-setup-capf ()
    (add-hook 'completion-at-point-functions #'tempel-complete -100 'local))

  (add-hook 'prog-mode-hook 'tempel-setup-capf)
  (add-hook 'text-mode-hook 'tempel-setup-capf)
  (add-hook 'lsp-mode-hook 'tempel-setup-capf)

Define keymaps, the defaults are unnecessarily hard to trigger.

  (general-define-key
    :keymaps '(insert normal)
    "C-n" 'nil
    "C-p" 'nil)
  (general-define-key
    :keymaps 'tempel-map
    "M-{" nil
    "M-}" nil
    "C-n" 'tempel-next
    "C-p" 'tempel-previous)

Fix LSP not getting notified about changes, can be fixed by notifying it at the end of template expansion.

  (advice-add
   'tempel--disable
   :before
   (lambda (&rest r)
     (when lsp-mode
       (let* ((region-start (tempel--beginning))
              (region-end (tempel--end)))
         (lsp-on-change region-start region-end (- region-end region-start))))))

To setup a post template return point, use (tempel-retpoint-here) in a template.

  (defun org-edit-special-latex-preview (&rest _)
    (let ((datum (org-element-context)))
      (when (and (memq (org-element-type datum) '(latex-environment latex-fragment))
                 (let ((beg (org-element-property :begin datum))
                       (end (org-element-property :end datum)))
                   (when (org-clear-latex-preview beg end)
                     (setq-local tempel-latex-preview t)))))))

  (advice-add
   'org-edit-special
   :before
   #'org-edit-special-latex-preview)

  (defvar-local tempel-retpoint (make-marker))
  (defvar-local tempel-latex-preview nil)

  (defun tempel-retpoint-here ()
    "Place a marker at `point' to allow for return on tempel exit."
    (set-marker tempel-retpoint (point))
    "")

  (defun tempel-retpoint-goto ()
    "Move `point' to `tempel-retpoint'."
    (when (marker-position tempel-retpoint)
      (goto-char (marker-position tempel-retpoint))
      (set-marker tempel-retpoint nil)))

  (add-hook
   'tempel--disable
   #'tempel-retpoint-goto)

  (defvar org-src-mode-exit-hook nil)

  (defun org-edit-src-exit-run-hooks (&rest _)
    "Run hooks from `org-edit-src-exit-hook' upon exiting org-src edit buffer."
    (run-hooks 'org-src-mode-exit-hook))

  (advice-add
   'org-edit-src-exit
   :after
   #'org-edit-src-exit-run-hooks)

  (defun org-edit-src-exit-tempel-retpoint ()
    "Return to `tempel-retpoint' if set."
    (tempel-retpoint-goto))

  (defun org-edit-src-exit-tempel-latex-preview ()
    "Toggle LaTeX preview of templated LaTeX fragment."
    (when tempel-latex-preview
      (org-latex-preview)
      (setq-local tempel-latex-preview nil)))

  (add-hook
   'org-src-mode-exit-hook
   #'org-edit-src-exit-tempel-latex-preview)

  (add-hook
   'org-src-mode-exit-hook
   #'org-edit-src-exit-tempel-retpoint)

  (defun tempel-post-edit-latex (&optional preview move-back)
    "Move `point' back and run `org-edit-special'.
  If PREVIEW is non-nil then `org-latex-preview' will be called on
  the resulting LaTeX block.  Move point that MOVE-BACK lines back to
  reach a good spot in the LaTeX block, defaults to `-2'."
    (forward-line (or move-back -2))
    (end-of-line)
    (setq-local tempel-latex-preview preview)
    (org-edit-special))

To allow for => as template keys, 'symbol won't work, but 'evil-word will.

  (defun tempel--prefix-bounds ()
  "Return prefix bounds."
  (if tempel-trigger-prefix
      (let ((end (point))
            (beg (save-excursion
                   (search-backward tempel-trigger-prefix
                                    (line-beginning-position) 'noerror))))
        (when (and beg (save-excursion
                         (not (re-search-backward "\\s-" beg 'noerror))))
          (cons (+ beg (length tempel-trigger-prefix)) end)))
    (bounds-of-thing-at-point 'symbol)))