Auto-linkify note links

sundown/autolink.c

@@ -29,8 +29,9 @@
 int
 sd_autolink_issafe(const uint8_t *link, size_t link_len)
 {
-	static const size_t valid_uris_count = 5;
+	static const size_t valid_uris_count = 6;
 	static const char *valid_uris[] = {
+		"§",
 		"/", "http://", "https://", "ftp://", "mailto:"
 	};
 
@@ -295,3 +296,35 @@ sd_autolink__url(
 	return link_end;
 }
 
+size_t
+sd_autolink__zet(
+	size_t *rewind_p,
+	struct buf *link,
+	uint8_t *data,
+	size_t max_rewind,
+	size_t size,
+	unsigned int flags)
+{
+	size_t link_end, rewind = 0, domain_len;
+
+	static const char sigil_size = sizeof("§")-1;
+
+	if (size < sigil_size || strncmp(data, "§", sigil_size))
+		return 0;
+
+	while (rewind < max_rewind && isalpha(data[-rewind - 1]))
+		rewind++;
+
+	if (!sd_autolink_issafe(data - rewind, size + rewind))
+		return 0;
+
+	link_end = sigil_size;
+
+	while (link_end < size && isxdigit(data[link_end]))
+		link_end++;
+
+	bufput(link, data - rewind, link_end + rewind);
+	*rewind_p = rewind;
+
+	return link_end;
+}

sundown/autolink.h

@@ -42,6 +42,10 @@ size_t
 sd_autolink__url(size_t *rewind_p, struct buf *link,
 	uint8_t *data, size_t offset, size_t size, unsigned int flags);
 
+size_t
+sd_autolink__zet(size_t *rewind_p, struct buf *link,
+	uint8_t *data, size_t offset, size_t size, unsigned int flags);
+
 #ifdef __cplusplus
 }
 #endif

sundown/html.c

@@ -86,10 +86,15 @@ rndr_autolink(struct buf *ob, const struct buf *link, enum mkd_autolink type, vo
 		type != MKDA_EMAIL)
 		return 0;
 
+	static const char zet_sigil_size = sizeof("§")-1;
+
 	BUFPUTSL(ob, "<a href=\"");
 	if (type == MKDA_EMAIL)
 		BUFPUTSL(ob, "mailto:");
-	escape_href(ob, link->data, link->size);
+	if (type == MKDA_ZET)
+		escape_href(ob, link->data + zet_sigil_size, link->size - zet_sigil_size);
+	else
+		escape_href(ob, link->data, link->size);
 
 	if (options->link_attributes) {
 		bufputc(ob, '\"');

sundown/markdown.c

@@ -72,6 +72,7 @@ static size_t char_langle_tag(struct buf *ob, struct sd_markdown *rndr, uint8_t
 static size_t char_autolink_url(struct buf *ob, struct sd_markdown *rndr, uint8_t *data, size_t offset, size_t size);
 static size_t char_autolink_email(struct buf *ob, struct sd_markdown *rndr, uint8_t *data, size_t offset, size_t size);
 static size_t char_autolink_www(struct buf *ob, struct sd_markdown *rndr, uint8_t *data, size_t offset, size_t size);
+static size_t char_autolink_zet(struct buf *ob, struct sd_markdown *rndr, uint8_t *data, size_t offset, size_t size);
 static size_t char_link(struct buf *ob, struct sd_markdown *rndr, uint8_t *data, size_t offset, size_t size);
 static size_t char_superscript(struct buf *ob, struct sd_markdown *rndr, uint8_t *data, size_t offset, size_t size);
 
@@ -87,6 +88,7 @@ enum markdown_char_t {
 	MD_CHAR_AUTOLINK_URL,
 	MD_CHAR_AUTOLINK_EMAIL,
 	MD_CHAR_AUTOLINK_WWW,
+	MD_CHAR_AUTOLINK_ZET,
 	MD_CHAR_SUPERSCRIPT,
 };
 
@@ -102,6 +104,7 @@ static char_trigger markdown_char_ptrs[] = {
 	&char_autolink_url,
 	&char_autolink_email,
 	&char_autolink_www,
+	&char_autolink_zet,
 	&char_superscript,
 };
 
@@ -837,6 +840,26 @@ char_autolink_url(struct buf *ob, struct sd_markdown *rndr, uint8_t *data, size_
 	return link_len;
 }
 
+static size_t
+char_autolink_zet(struct buf *ob, struct sd_markdown *rndr, uint8_t *data, size_t offset, size_t size)
+{
+	struct buf *link;
+	size_t link_len, rewind;
+
+	if (!rndr->cb.link || rndr->in_link_body)
+		return 0;
+
+	link = rndr_newbuf(rndr, BUFFER_SPAN);
+
+	if ((link_len = sd_autolink__zet(&rewind, link, data, offset, size, 0)) > 0) {
+		ob->size -= rewind;
+		rndr->cb.autolink(ob, link, MKDA_ZET, rndr->opaque);
+	}
+
+	rndr_popbuf(rndr, BUFFER_SPAN);
+	return link_len;
+}
+
 /* char_link • '[': parsing a link or an image */
 static size_t
 char_link(struct buf *ob, struct sd_markdown *rndr, uint8_t *data, size_t offset, size_t size)
@@ -2439,6 +2462,7 @@ sd_markdown_new(
 		md->active_char[':'] = MD_CHAR_AUTOLINK_URL;
 		md->active_char['@'] = MD_CHAR_AUTOLINK_EMAIL;
 		md->active_char['w'] = MD_CHAR_AUTOLINK_WWW;
+		md->active_char[194] = MD_CHAR_AUTOLINK_ZET;
 	}
 
 	if (extensions & MKDEXT_SUPERSCRIPT)

sundown/markdown.h

@@ -40,6 +40,7 @@ enum mkd_autolink {
 	MKDA_NOT_AUTOLINK,	/* used internally when it is not an autolink*/
 	MKDA_NORMAL,		/* normal http/http/ftp/mailto/etc link */
 	MKDA_EMAIL,			/* e-mail link without explit mailto: */
+	MKDA_ZET,			  /* zet link */
 };
 
 enum mkd_tableflags {