Add cape-elisp-block

3 files changed, 79 insertions, 48 deletions

diff --git a/CHANGELOG.org b/CHANGELOG.org
index 82fa344..ae1c113 100644
--- a/CHANGELOG.org
+++ b/CHANGELOG.org
@@ -16,6 +16,8 @@
   =dabbrev-case-replace=.
 - =cape-dict-case-fold=: New variable to configure if case is ignored
   during search and completion.
+- =cape-elisp-block=: Complete Elisp in Org or Markdown code block. This Capf is
+  particularly useful for literate Emacs configurations.
 
 * Version 0.13 (2023-02-15)
 
diff --git a/README.org b/README.org
index 085edba..83ee711 100644
--- a/README.org
+++ b/README.org
@@ -36,15 +36,16 @@ advantage of Company backends even if you are not using Company as frontend.
 
 * Available Capfs
 
-+ ~cape-dabbrev~: Complete word from current buffers (see also ~dabbrev-capf~ on
-  Emacs 29)
-+ ~cape-file~: Complete file name
-+ ~cape-history~: Complete from Eshell, Comint or minibuffer history
-+ ~cape-keyword~: Complete programming language keyword
-+ ~cape-symbol~: Complete Elisp symbol
-+ ~cape-abbrev~: Complete abbreviation (~add-global-abbrev~, ~add-mode-abbrev~)
-+ ~cape-dict~: Complete word from dictionary file
-+ ~cape-line~: Complete entire line from current buffer
++ ~cape-dabbrev~: Complete word from current buffers. See also ~dabbrev-capf~ on
+  Emacs 29.
++ ~cape-elisp-block~: Complete Elisp in Org or Markdown code block.
++ ~cape-file~: Complete file name.
++ ~cape-history~: Complete from Eshell, Comint or minibuffer history.
++ ~cape-keyword~: Complete programming language keyword.
++ ~cape-symbol~: Complete Elisp symbol.
++ ~cape-abbrev~: Complete abbreviation (~add-global-abbrev~, ~add-mode-abbrev~).
++ ~cape-dict~: Complete word from dictionary file.
++ ~cape-line~: Complete entire line from current buffer.
 + ~cape-tex~: Complete Unicode char from TeX command, e.g. ~\hbar~.
 + ~cape-sgml~: Complete Unicode char from SGML entity, e.g., ~&alpha~.
 + ~cape-rfc1345~: Complete Unicode char using RFC 1345 mnemonics.
@@ -56,45 +57,47 @@ Cape is available on GNU ELPA and MELPA. You can install the package with
 could be upstreamed into Emacs itself.
 
 #+begin_src emacs-lisp
-  ;; Enable Corfu completion UI
-  ;; See the Corfu README for more configuration tips.
-  (use-package corfu
-    :init
-    (global-corfu-mode))
-
-  ;; Add extensions
-  (use-package cape
-    ;; Bind dedicated completion commands
-    ;; Alternative prefix keys: C-c p, M-p, M-+, ...
-    :bind (("C-c p p" . completion-at-point) ;; capf
-           ("C-c p t" . complete-tag)        ;; etags
-           ("C-c p d" . cape-dabbrev)        ;; or dabbrev-completion
-           ("C-c p h" . cape-history)
-           ("C-c p f" . cape-file)
-           ("C-c p k" . cape-keyword)
-           ("C-c p s" . cape-symbol)
-           ("C-c p a" . cape-abbrev)
-           ("C-c p l" . cape-line)
-           ("C-c p w" . cape-dict)
-           ("C-c p \\" . cape-tex)
-           ("C-c p _" . cape-tex)
-           ("C-c p ^" . cape-tex)
-           ("C-c p &" . cape-sgml)
-           ("C-c p r" . cape-rfc1345))
-    :init
-    ;; Add `completion-at-point-functions', used by `completion-at-point'.
-    (add-to-list 'completion-at-point-functions #'cape-dabbrev)
-    (add-to-list 'completion-at-point-functions #'cape-file)
-    ;;(add-to-list 'completion-at-point-functions #'cape-history)
-    ;;(add-to-list 'completion-at-point-functions #'cape-keyword)
-    ;;(add-to-list 'completion-at-point-functions #'cape-tex)
-    ;;(add-to-list 'completion-at-point-functions #'cape-sgml)
-    ;;(add-to-list 'completion-at-point-functions #'cape-rfc1345)
-    ;;(add-to-list 'completion-at-point-functions #'cape-abbrev)
-    ;;(add-to-list 'completion-at-point-functions #'cape-dict)
-    ;;(add-to-list 'completion-at-point-functions #'cape-symbol)
-    ;;(add-to-list 'completion-at-point-functions #'cape-line)
-  )
+;; Enable Corfu completion UI
+;; See the Corfu README for more configuration tips.
+(use-package corfu
+  :init
+  (global-corfu-mode))
+
+;; Add extensions
+(use-package cape
+  ;; Bind dedicated completion commands
+  ;; Alternative prefix keys: C-c p, M-p, M-+, ...
+  :bind (("C-c p p" . completion-at-point) ;; capf
+         ("C-c p t" . complete-tag)        ;; etags
+         ("C-c p d" . cape-dabbrev)        ;; or dabbrev-completion
+         ("C-c p h" . cape-history)
+         ("C-c p f" . cape-file)
+         ("C-c p k" . cape-keyword)
+         ("C-c p s" . cape-symbol)
+         ("C-c p a" . cape-abbrev)
+         ("C-c p l" . cape-line)
+         ("C-c p w" . cape-dict)
+         ("C-c p \\" . cape-tex)
+         ("C-c p _" . cape-tex)
+         ("C-c p ^" . cape-tex)
+         ("C-c p &" . cape-sgml)
+         ("C-c p r" . cape-rfc1345))
+  :init
+  ;; Add `completion-at-point-functions', used by `completion-at-point'.
+  ;; NOTE: The order matters!
+  (add-to-list 'completion-at-point-functions #'cape-dabbrev)
+  (add-to-list 'completion-at-point-functions #'cape-file)
+  (add-to-list 'completion-at-point-functions #'cape-elisp-block)
+  ;;(add-to-list 'completion-at-point-functions #'cape-history)
+  ;;(add-to-list 'completion-at-point-functions #'cape-keyword)
+  ;;(add-to-list 'completion-at-point-functions #'cape-tex)
+  ;;(add-to-list 'completion-at-point-functions #'cape-sgml)
+  ;;(add-to-list 'completion-at-point-functions #'cape-rfc1345)
+  ;;(add-to-list 'completion-at-point-functions #'cape-abbrev)
+  ;;(add-to-list 'completion-at-point-functions #'cape-dict)
+  ;;(add-to-list 'completion-at-point-functions #'cape-symbol)
+  ;;(add-to-list 'completion-at-point-functions #'cape-line)
+)
 #+end_src
 
 * CAPF adapters and transformers
diff --git a/cape.el b/cape.el
index b51a94a..bda53cd 100644
--- a/cape.el
+++ b/cape.el
@@ -387,6 +387,32 @@ If INTERACTIVE is nil the function acts like a Capf."
         ,(cape--table-with-properties obarray :category 'symbol)
         ,@cape--symbol-properties))))
 
+;;;;; cape-elisp-block
+
+(declare-function org-element-at-point "org-element")
+(declare-function markdown-code-block-lang "ext:markdown-mode")
+
+;;;###autoload
+(defun cape-elisp-block (&optional interactive)
+  "Complete Elisp in Org or Markdown code block.
+This Capf is particularly useful for literate Emacs configurations.
+If INTERACTIVE is nil the function acts like a Capf."
+  (interactive (list t))
+  (if interactive
+      (cape-interactive #'cape-elisp-block)
+    (when-let ((face (get-text-property (point) 'face))
+               (lang (or (and (if (listp face)
+                                  (memq 'org-block face)
+                                (eq 'org-block face))
+                              (plist-get (cadr (org-element-at-point)) :language))
+                         (and (if (listp face)
+                                  (memq 'markdown-code-face face)
+                                (eq 'markdown-code-face face))
+                              (save-excursion
+                                (markdown-code-block-lang)))))
+               ((member lang '("elisp" "emacs-lisp"))))
+      (elisp-completion-at-point))))
+
 ;;;;; cape-dabbrev
 
 (defvar cape--dabbrev-properties