Add support for backslash escape in wikilinks

src/parser/inlines.rs

@@ -1730,7 +1730,7 @@ impl<'a, 'r, 'o, 'c, 'd, 'i> Subject<'a, 'r, 'o, 'c, 'd, 'i> {
         let startpos = self.pos;
         let component = self.wikilink_url_link_label()?;
         let url_clean = strings::clean_url(component.url);
-        let (link_label, link_label_start_column, link_label_end_column) =
+        let (link_label, link_label_start_column, _link_label_end_column) =
             match component.link_label {
                 Some((label, sc, ec)) => (entity::unescape_html(label), sc, ec),
                 None => (
@@ -1744,11 +1744,8 @@ impl<'a, 'r, 'o, 'c, 'd, 'i> Subject<'a, 'r, 'o, 'c, 'd, 'i> {
             url: String::from_utf8(url_clean).unwrap(),
         };
         let inl = self.make_inline(NodeValue::WikiLink(nl), startpos - 1, self.pos - 1);
-        inl.append(self.make_inline(
-            NodeValue::Text(String::from_utf8(link_label).unwrap()),
-            link_label_start_column,
-            link_label_end_column,
-        ));
+
+        self.label_backslash_escapes(inl, link_label, link_label_start_column);
 
         Some(inl)
     }
@@ -1844,6 +1841,63 @@ impl<'a, 'r, 'o, 'c, 'd, 'i> Subject<'a, 'r, 'o, 'c, 'd, 'i> {
         true
     }
 
+    // Given a label, handles backslash escaped characters. Appends the resulting
+    // nodes to the container
+    fn label_backslash_escapes(
+        &mut self,
+        container: &'a AstNode<'a>,
+        label: Vec<u8>,
+        start_column: usize,
+    ) {
+        let mut startpos = 0;
+        let mut offset = 0;
+        let len = label.len();
+
+        while offset < len {
+            let c = label[offset];
+
+            if c == b'\\' && (offset + 1) < len && ispunct(label[offset + 1]) {
+                let preceding_text = self.make_inline(
+                    NodeValue::Text(String::from_utf8(label[startpos..offset].to_owned()).unwrap()),
+                    start_column + startpos,
+                    start_column + offset - 1,
+                );
+
+                container.append(preceding_text);
+
+                let inline_text = self.make_inline(
+                    NodeValue::Text(String::from_utf8(vec![label[offset + 1]]).unwrap()),
+                    start_column + offset,
+                    start_column + offset + 1,
+                );
+
+                if self.options.render.escaped_char_spans {
+                    let span = self.make_inline(
+                        NodeValue::Escaped,
+                        start_column + offset,
+                        start_column + offset + 1,
+                    );
+
+                    span.append(inline_text);
+                    container.append(span);
+                } else {
+                    container.append(inline_text);
+                }
+
+                offset += 2;
+                startpos = offset;
+            } else {
+                offset += 1;
+            }
+        }
+
+        container.append(self.make_inline(
+            NodeValue::Text(String::from_utf8(label[startpos..offset].to_owned()).unwrap()),
+            start_column + startpos,
+            start_column + offset - 1,
+        ));
+    }
+
     pub fn spnl(&mut self) {
         self.skip_spaces();
         if self.skip_line_end() {

src/tests/fixtures/wikilinks_title_after_pipe.md

@@ -44,4 +44,26 @@ HTML entities are recognized both in the name of page and in the link title.
 [[Geschütztes Leerzeichen|Über  ]]
 .
 <p><a href="Gesch%C3%BCtztes%20Leerzeichen" data-wikilink="true">Über &amp;nbsp;</a></p>
-````````````````````````````````
+````````````````````````````````
+
+Escaping characters is supported
+
+```````````````````````````````` example
+[[https://example.org|foo\[\]bar]]
+.
+<p><a href="https://example.org" data-wikilink="true">foo[]bar</a></p>
+````````````````````````````````
+
+```````````````````````````````` example
+[[Name \[of\] page]]
+.
+<p><a href="Name%20%5Bof%5D%20page" data-wikilink="true">Name [of] page</a></p>
+````````````````````````````````
+
+Emphasis or other inline markdown is not supported
+
+```````````````````````````````` example
+[[Name _of_ page]]
+.
+<p><a href="Name%20_of_%20page" data-wikilink="true">Name _of_ page</a></p>
+````````````````````````````````

src/tests/fixtures/wikilinks_title_before_pipe.md

@@ -52,4 +52,26 @@ HTML entities are recognized both in the name of page and in the link title.
 [[Über  |Geschütztes Leerzeichen]]
 .
 <p><a href="Gesch%C3%BCtztes%20Leerzeichen" data-wikilink="true">Über &amp;nbsp;</a></p>
-````````````````````````````````
+````````````````````````````````
+
+Escaping characters is supported
+
+```````````````````````````````` example
+[[foo\[\]bar|https://example.org]]
+.
+<p><a href="https://example.org" data-wikilink="true">foo[]bar</a></p>
+````````````````````````````````
+
+```````````````````````````````` example
+[[Name \[of\] page]]
+.
+<p><a href="Name%20%5Bof%5D%20page" data-wikilink="true">Name [of] page</a></p>
+````````````````````````````````
+
+Emphasis or other inline markdown is not supported
+
+```````````````````````````````` example
+[[Name _of_ page]]
+.
+<p><a href="Name%20_of_%20page" data-wikilink="true">Name _of_ page</a></p>
+````````````````````````````````

src/tests/wikilinks.rs

@@ -47,6 +47,16 @@ fn wikilinks_sanitizes_the_href_attribute_case_2() {
     );
 }
 
+#[test]
+fn wikilinks_title_escape_chars() {
+    html_opts!(
+        [extension.wikilinks_title_before_pipe, render.escaped_char_spans],
+        concat!("[[Name \\[of\\] page|http://example.com]]",),
+        concat!("<p><a href=\"http://example.com\" data-wikilink=\"true\">Name <span data-escaped-char>[</span>of<span data-escaped-char>]</span> page</a></p>\n"),
+        no_roundtrip,
+    );
+}
+
 #[test]
 fn wikilinks_supercedes_relaxed_autolinks() {
     html_opts!(
@@ -228,4 +238,20 @@ fn sourcepos() {
             ])
         ])
     );
+
+    assert_ast_match!(
+        [extension.wikilinks_title_before_pipe],
+        "This [[link\\[label|http://example.com]] that\n",
+        (document (1:1-1:44) [
+            (paragraph (1:1-1:44) [
+                (text (1:1-1:5) "This ")
+                (wikilink (1:6-1:39) [
+                    (text (1:8-1:11) "link")
+                    (text (1:12-1:13) "[")
+                    (text (1:14-1:18) "label")
+                ])
+                (text (1:40-1:44) " that")
+            ])
+        ])
+    );
 }