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Literate Org Haskell
(defconst fn/haskell-file-extension ".hs"
"The de facto haskell file extension.")
(defun fn/add-haskell-file-extension (name)
"Add the extension of .hs to a file or buffer NAME."
(if (string/ends-with name fn/haskell-file-extension)
name (concat name fn/haskell-file-extension)))
(defvar fn/org-haskell-mode-hook nil
"Hook when buffer is haskellized.")
(defun fn/haskellize-buffer-file (&optional buffer)
"Renames an BUFFER with a .hs extension if it doesn't have one."
(with-current-buffer (or buffer (current-buffer))
(lexical-let ((name (buffer-name))
(file-name (buffer-file-name)))
(if (not (and file-name (file-exists-p file-name)))
(error "Buffer '%s' has no backing file" name)
(lexical-let ((haskellized-name (fn/add-haskell-file-extension name))
(haskellized-file-name (fn/add-haskell-file-extension file-name)))
((get-buffer haskellized-name)
(error "A buffer named '%s' already exists" haskellized-name))
((string-equal name haskellized-name)
(message "Buffer %s is already haskellized" haskellized-name))
(rename-file file-name haskellized-file-name t)
(rename-buffer haskellized-name)
(set-visited-file-name haskellized-file-name)
(set-buffer-modified-p nil)
(message "Buffer %s is now haskellized" haskellized-name))))))))
(defun fn/org-haskell-buffer-p (&optional buffer)
"Check if BUFFER is an org-haskell buffer."
(with-current-buffer (or buffer (current-buffer))
(and (eq major-mode 'haskell-mode)
(fboundp 'org-src-edit-buffer-p)
(defun fn/haskellize-org-haskell-buffer (&rest _)
"Haskellize org haskell buffer."
(when (fn/org-haskell-buffer-p)
(fn/haskellize-buffer-file (current-buffer))
(run-hooks 'fn/org-haskell-mode-hook)))
(defun fn/save-org-haskell-buffer (&rest _)
"Save haskell buffer along with the edit buffer."
(when (fn/org-haskell-buffer-p)
(defun fn/cleanup-org-haskell-buffer (orig-fun &rest args)
"Cleanup the org-haskell buffer when exiting the edit buffer."
(lexical-let ((org-haskell-file-name (buffer-file-name))
(org-haskell-buffer-p (fn/org-haskell-buffer-p)))
(apply orig-fun args)
(when (and (file-exists-p org-haskell-file-name) org-haskell-buffer-p)
(delete-file org-haskell-file-name))))))
(add-hook 'org-src-mode-hook #'fn/haskellize-org-haskell-buffer t)
(advice-add 'org-edit-src-save :before #'fn/save-org-haskell-buffer)
(advice-add 'org-edit-src-exit :around #'fn/cleanup-org-haskell-buffer)
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