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Diffstat (limited to 'seam-html.el')
| -rw-r--r-- | seam-html.el | 363 |
1 files changed, 363 insertions, 0 deletions
diff --git a/seam-html.el b/seam-html.el new file mode 100644 index 0000000..8f4731c --- /dev/null +++ b/seam-html.el @@ -0,0 +1,363 @@ +;;; seam-html.el --- Seam HTML exporter -*- lexical-binding: t -*- + +;; Copyright (c) 2025 Spencer Williams + +;; Author: Spencer Williams <spnw@plexwave.org> + +;; SPDX-License-Identifier: GPL-3.0-or-later + +;; This file is not part of GNU Emacs. + +;; This program is free software: you can redistribute it and/or modify +;; it under the terms of the GNU General Public License as published by +;; the Free Software Foundation, either version 3 of the License, or +;; (at your option) any later version. + +;; This program is distributed in the hope that it will be useful, +;; but WITHOUT ANY WARRANTY; without even the implied warranty of +;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;; GNU General Public License for more details. + +;; You should have received a copy of the GNU General Public License +;; along with this program. If not, see <http://www.gnu.org/licenses/>. + +;;; Commentary: + +;; Seam's HTML exporter. +;; +;; This was blithely hacked together using large chunks of code lifted +;; straight from ox-html.el, and could do with much improvement. +;; +;; Original ox-html code is licensed under GPL v3+. Copyright (c) +;; 2011-2025 Free Software Foundation, Inc. Original authors: Carsten +;; Dominik <carsten.dominik@gmail.com> and Jambunathan K <kjambunathan +;; at gmail dot com>. + +;;; Code: + +(require 'ox-html) + +;;; NOTE: This function does not respect `:headline-levels' or +;;; `:html-self-link-headlines'. +(defun seam-html-headline (headline contents info) + "Transcode a HEADLINE element from Org to HTML. +CONTENTS holds the contents of the headline. INFO is a plist +holding contextual information." + (cond + ((org-element-property :SEAM-TITLE-P headline) + contents) + ((org-element-property :footnote-section-p headline) + nil) + (t + (let* ((level (+ (org-export-get-relative-level headline info) + (1- (plist-get info :html-toplevel-hlevel)))) + (text (org-export-data (org-element-property :title headline) info)) + (contents (or contents "")) + (id (org-html--reference headline info)) + (todo (and (plist-get info :with-todo-keywords) + (let ((todo (org-element-property :todo-keyword headline))) + (and todo (org-export-data todo info))))) + (todo-type (and todo (org-element-property :todo-type headline))) + (priority (and (plist-get info :with-priority) + (org-element-property :priority headline))) + (tags (and (plist-get info :with-tags) + (org-export-get-tags headline info))) + (full-text (funcall (plist-get info :html-format-headline-function) + todo todo-type priority text tags info))) + (let ((headline-class + (org-element-property :HTML_HEADLINE_CLASS headline))) + (format "%s%s\n" + (format "<h%d id=\"%s\"%s>%s</h%d>\n" + level + id + (if (not headline-class) "" + (format " class=\"%s\"" headline-class)) + full-text + level) + contents)))))) + +(defun seam-html-section (_section contents _info) + "Transcode a SECTION element from Org to HTML. +CONTENTS holds the contents of the section." + contents) + +(defvar seam-html-standalone-image-predicate) +(defun seam-html-standalone-image-p (element info) + "Non-nil if ELEMENT is a standalone image. + +INFO is a plist holding contextual information. + +An element or object is a standalone image when + + - its type is `paragraph' and its sole content, save for white + spaces, is a link that qualifies as an inline image; + + - its type is `link' and its containing paragraph has no other + content save white spaces. + +Bind `seam-html-standalone-image-predicate' to constrain paragraph +further. For example, to check for only captioned standalone +images, set it to: + + (lambda (paragraph) (org-element-property :caption paragraph))" + (let ((paragraph (pcase (org-element-type element) + (`paragraph element) + (`link (org-element-parent element))))) + (and (org-element-type-p paragraph 'paragraph) + (or (not (and (boundp 'seam-html-standalone-image-predicate) + (fboundp seam-html-standalone-image-predicate))) + (funcall seam-html-standalone-image-predicate paragraph)) + (catch 'exit + (let ((link-count 0)) + (org-element-map (org-element-contents paragraph) + (cons 'plain-text org-element-all-objects) + (lambda (obj) + (when (pcase (org-element-type obj) + (`plain-text (org-string-nw-p obj)) + (`link (or (> (cl-incf link-count) 1) + (not (org-html-inline-image-p obj info)))) + (_ t)) + (throw 'exit nil))) + info nil 'link) + (= link-count 1)))))) + +(defun seam-html-link (link desc info) + "Transcode a LINK object from Org to HTML. +DESC is the description part of the link, or the empty string. +INFO is a plist holding contextual information. See +`org-export-data'." + (let* ((html-ext (plist-get info :html-extension)) + (dot (when (> (length html-ext) 0) ".")) + (link-org-files-as-html-maybe + (lambda (raw-path info) + ;; Treat links to `file.org' as links to `file.html', if + ;; needed. See `org-html-link-org-files-as-html'. + (save-match-data + (cond + ((and (plist-get info :html-link-org-files-as-html) + (let ((case-fold-search t)) + (string-match "\\(.+\\)\\.org\\(?:\\.gpg\\)?$" raw-path))) + (concat (match-string 1 raw-path) dot html-ext)) + (t raw-path))))) + (link-type (org-element-property :type link)) + (raw-path (org-element-property :path link)) + ;; Ensure DESC really exists, or set it to nil. + (desc (org-string-nw-p desc)) + (path + (cond + ((string= "seam" link-type) + (let ((slug raw-path)) + (when-let ((file (seam-lookup-slug slug))) + (let ((type (seam-get-note-type file))) + (when (and (member type seam-export--types) + (file-exists-p (seam-make-file-name slug type))) + (concat seam-export--root-path + slug + (if seam-export--no-extension "" ".html"))))))) + ((string= "file" link-type) + ;; During publishing, turn absolute file names belonging + ;; to base directory into relative file names. Otherwise, + ;; append "file" protocol to absolute file name. + (setq raw-path + (org-export-file-uri + (org-publish-file-relative-name raw-path info))) + ;; Possibly append `:html-link-home' to relative file + ;; name. + (let ((home (and (plist-get info :html-link-home) + (org-trim (plist-get info :html-link-home))))) + (when (and home + (plist-get info :html-link-use-abs-url) + (not (file-name-absolute-p raw-path))) + (setq raw-path (concat (file-name-as-directory home) raw-path)))) + ;; Maybe turn ".org" into ".html". + (setq raw-path (funcall link-org-files-as-html-maybe raw-path info)) + ;; Add search option, if any. A search option can be + ;; relative to a custom-id, a headline title, a name or + ;; a target. + (let ((option (org-element-property :search-option link))) + (if (not option) raw-path + (let ((path (org-element-property :path link))) + (concat raw-path + "#" + (org-publish-resolve-external-link option path t)))))) + (t (url-encode-url (concat link-type ":" raw-path))))) + (attributes-plist + (org-combine-plists + ;; Extract attributes from parent's paragraph. HACK: Only + ;; do this for the first link in parent (inner image link + ;; for inline images). This is needed as long as + ;; attributes cannot be set on a per link basis. + (let* ((parent (org-element-parent-element link)) + (link (let ((container (org-element-parent link))) + (if (and (org-element-type-p container 'link) + (org-html-inline-image-p link info)) + container + link)))) + (and (eq link (org-element-map parent 'link #'identity info t)) + (org-export-read-attribute :attr_html parent))) + ;; Also add attributes from link itself. Currently, those + ;; need to be added programmatically before `org-html-link' + ;; is invoked, for example, by backends building upon HTML + ;; export. + (org-export-read-attribute :attr_html link))) + (attributes + (let ((attr (org-html--make-attribute-string attributes-plist))) + (if (org-string-nw-p attr) (concat " " attr) "")))) + (cond + ;; Link type is handled by a special function. + ((org-export-custom-protocol-maybe link desc 'html info)) + ;; Image file. + ((and (plist-get info :html-inline-images) + (org-export-inline-image-p + link (plist-get info :html-inline-image-rules))) + (org-html--format-image path attributes-plist info)) + ;; Radio target: Transcode target's contents and use them as + ;; link's description. + ((string= link-type "radio") + (let ((destination (org-export-resolve-radio-link link info))) + (if (not destination) desc + (format "<a href=\"#%s\"%s>%s</a>" + (org-export-get-reference destination info) + attributes + desc)))) + ;; Links pointing to a headline: Find destination and build + ;; appropriate referencing command. + ((member link-type '("custom-id" "fuzzy" "id")) + (let ((destination (if (string= link-type "fuzzy") + (org-export-resolve-fuzzy-link link info) + (org-export-resolve-id-link link info)))) + (pcase (org-element-type destination) + ;; ID link points to an external file. + (`plain-text + (let ((fragment (concat org-html--id-attr-prefix raw-path)) + ;; Treat links to ".org" files as ".html", if needed. + (path (funcall link-org-files-as-html-maybe + destination info))) + (format "<a href=\"%s#%s\"%s>%s</a>" + path fragment attributes (or desc destination)))) + ;; Fuzzy link points nowhere. + (`nil + (;; format "<i>%s</i>" + identity + (or desc + (org-export-data + (org-element-property :raw-link link) info)))) + ;; Link points to a headline. + (`headline + (let ((href (org-html--reference destination info)) + ;; What description to use? + (desc + ;; Case 1: Headline is numbered and LINK has no + ;; description. Display section number. + (if (and (org-export-numbered-headline-p destination info) + (not desc)) + (mapconcat #'number-to-string + (org-export-get-headline-number + destination info) ".") + ;; Case 2: Either the headline is un-numbered or + ;; LINK has a custom description. Display LINK's + ;; description or headline's title. + (or desc + (org-export-data + (org-element-property :title destination) info))))) + (format "<a href=\"#%s\"%s>%s</a>" href attributes desc))) + ;; Fuzzy link points to a target or an element. + (_ + (if (and destination + (memq (plist-get info :with-latex) '(mathjax t)) + (org-element-type-p destination 'latex-environment) + (eq 'math (org-latex--environment-type destination))) + ;; Caption and labels are introduced within LaTeX + ;; environment. Use "ref" or "eqref" macro, depending on user + ;; preference to refer to those in the document. + (format (plist-get info :html-equation-reference-format) + (org-html--reference destination info)) + (let* ((ref (org-html--reference destination info)) + (seam-html-standalone-image-predicate + #'org-html--has-caption-p) + (counter-predicate + (if (org-element-type-p destination 'latex-environment) + #'org-html--math-environment-p + #'org-html--has-caption-p)) + (number + (cond + (desc nil) + ((seam-html-standalone-image-p destination info) + (org-export-get-ordinal + (org-element-map destination 'link #'identity info t) + info '(link) 'seam-html-standalone-image-p)) + (t (org-export-get-ordinal + destination info nil counter-predicate)))) + (desc + (cond (desc) + ((not number) "No description for this link") + ((numberp number) (number-to-string number)) + (t (mapconcat #'number-to-string number "."))))) + (format "<a href=\"#%s\"%s>%s</a>" ref attributes desc))))))) + ;; Coderef: replace link with the reference name or the + ;; equivalent line number. + ((string= link-type "coderef") + (let ((fragment (concat "coderef-" (org-html-encode-plain-text raw-path)))) + (format "<a href=\"#%s\" %s%s>%s</a>" + fragment + (format "class=\"coderef\" onmouseover=\"CodeHighlightOn(this, \ +'%s');\" onmouseout=\"CodeHighlightOff(this, '%s');\"" + fragment fragment) + attributes + (format (org-export-get-coderef-format raw-path desc) + (org-export-resolve-coderef raw-path info))))) + ;; External link with a description part. + ((and path desc) + (format "<a href=\"%s\"%s>%s</a>" + (org-html-encode-plain-text path) + attributes + desc)) + ;; External link without a description part. + (path + (let ((path (org-html-encode-plain-text path))) + (format "<a href=\"%s\"%s>%s</a>" path attributes path))) + ;; No path, only description. + (t desc)))) + + +(defun seam-html-src-block (src-block _contents info) + "Transcode a SRC-BLOCK element from Org to HTML. +CONTENTS holds the contents of the item. INFO is a plist holding +contextual information." + (if (org-export-read-attribute :attr_html src-block :textarea) + (org-html--textarea-block src-block) + (let* ((lang (org-element-property :language src-block)) + (code (org-html-format-code src-block info)) + (label (let ((lbl (org-html--reference src-block info t))) + (if lbl (format " id=\"%s\"" lbl) "")))) + (format "<pre>%s%s</pre>" + ;; Build caption. + (let ((caption (org-export-get-caption src-block))) + (if (not caption) "" + (let ((listing-number + (format + "<span class=\"listing-number\">%s </span>" + (format + (org-html--translate "Listing %d:" info) + (org-export-get-ordinal + src-block info nil #'org-html--has-caption-p))))) + (format "<label class=\"org-src-name\">%s%s</label>" + listing-number + (org-trim (org-export-data caption info)))))) + ;; Contents. + (format "<code class=\"src src-%s\"%s>%s</code>" + ;; Lang being nil is OK. + lang label code))))) + +(org-export-define-derived-backend + 'seam + 'html + :translate-alist + `((headline . seam-html-headline) + (link . seam-html-link) + (section . seam-html-section) + (src-block . seam-html-src-block))) + +(provide 'seam-html) + +;;; seam-html.el ends here |