feat: added option to add line numbers to code blocks

As requested in #176 code blocks can be configured to display
line numbers by adding a = to the specified language. e.g.

```python=
print("Hello Line Numbers!")
```

Author: redimp

otterwiki/renderer.py

@@ -58,7 +58,7 @@ def wrap(self, source):
         yield 0, '</pre></div>'
 
 
-def pygments_render(code, lang):
+def pygments_render(code, lang, linenumbers=False):
     try:
         lexer = get_lexer_by_name(lang, stripall=True)
     except ClassNotFound:
@@ -71,8 +71,8 @@ def pygments_render(code, lang):
                 mistune.escape(code.strip()),
             )
         )
-    formatter = CodeHtmlFormatter(classprefix=".highlight ")
-    # formatter = html.HtmlFormatter(classprefix=".highlight ")
+    linenos = "table" if linenumbers else None
+    formatter = CodeHtmlFormatter(classprefix=".highlight ", linenos=linenos)
     return highlight(code, lexer, formatter)
 
 
@@ -161,8 +161,9 @@ def clean_html(html: str) -> str:
             break
         try:
             if any(
-                x in element.attrs.keys() for x in REMOVE_ATTRIBUTES
-            ):  # pyright: ignore
+                x in element.attrs.keys()
+                for x in REMOVE_ATTRIBUTES  # pyright: ignore
+            ):
                 _escape = True
                 break
         except AttributeError:
@@ -209,7 +210,8 @@ def codespan(self, text):
 
     def block_code(self, code, info=None):
         prefix = ""
-        if not info:
+        linenumbers = False
+        if not info or not len(info):
             return (
                 '\n'
                 + _pre_copy_to_clipboard_tag()
@@ -218,6 +220,9 @@ def block_code(self, code, info=None):
         if cursormagicword in info:
             info = info.replace(cursormagicword, "")
             prefix = cursormagicword
+        if info[-1] == "=":
+            info = info[:-1]
+            linenumbers = True
         cursorline, code = hidemagicword(code)
         if info == "math":
             html = "".join(
@@ -232,7 +237,9 @@ def block_code(self, code, info=None):
             html = '\n<pre class="mermaid">{}\n</pre>\n'.format(code.strip())
             return html
         else:
-            html = prefix + pygments_render(code, info)
+            html = prefix + pygments_render(
+                code, info, linenumbers=linenumbers
+            )
         html = showmagicword(cursorline, html)
         return prefix + html
 

otterwiki/static/css/elements/page.css

@@ -116,3 +116,34 @@
 .page table > :last-child > tr:last-child > th {
     border-bottom: 0;
 }
+
+/* highlighttable with linenumbers */
+
+.highlight table.highlighttable {
+    width: 100%;
+    padding: 0;
+    margin: 0;
+    background-color: transparent;
+}
+
+.highlight table > tbody > tr > td.linenos {
+    padding: 0;
+    margin: 0;
+    width: 0;
+    border-right: 0;
+    background-color: transparent;
+}
+
+.highlight table > tbody > tr > td.linenos > div.linenodiv > pre {
+    background-color: rgba(0, 0, 0, 0.1);
+    margin-block-start: 0;
+    margin-block-end: 0;
+    border: 1px solid rgba(0,0,0,.05);
+}
+
+.page table > tbody > tr > td.code {
+    padding: 0;
+    border: 0;
+    margin: 0;
+    background-color: transparent;
+}

otterwiki/templates/snippets/syntax.html

@@ -195,6 +195,7 @@ <h4>{{ name }}</h4>
 </div>
 </div>
 
+
 <div class="row">
 <div class="col-md-6 col-sm-12 p-5">
 <pre>```
@@ -205,12 +206,18 @@ <h4>{{ name }}</h4>
 </div>
 </div>
 
+
+<div class="row">
+To add syntax highlighting, specify a language next to the backticks before the fenced code block.
+</div>
+
 <div class="row">
 <div class="col-md-6 col-sm-12 p-5">
 <pre class="block-compact">```python
 #!/usr/bin/env python
 assert 1 + 1 == 2
-print("Hello World!")```</pre>
+print("Hello World!")
+```</pre>
 </div>
 <div class="col-md-6 col-sm-12 p-5">
 <div class="highlight"><pre class="block-compact"><span></span><span class=".highlight ch">#!/usr/bin/env python</span>
@@ -220,6 +227,21 @@ <h4>{{ name }}</h4>
 </div>
 </div>
 
+<div class="row">
+To enable line numbers in the code block, append an equal sign <code>=</code> to the language.
+</div>
+<div class="row">
+<div class="col-md-6 col-sm-12 p-5">
+<pre class="block-compact">```python=
+print("Hello Line Numbers!")
+```</pre>
+</div>
+<div class="col-md-6 col-sm-12">
+<div class="highlight"><table class="highlighttable"><tbody><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span></pre></div></td><td class="code"><div><div class="copy-to-clipboard-outer"><div class="copy-to-clipboard-inner"><button class="btn alt-dm btn-xsm copy-to-clipboard" onclick="otterwiki.copy_to_clipboard(this);" type="button"><i "="" alt="Copy to clipboard" aria-hidden="true" class="fa fa-copy"></i></button></div><pre class="copy-to-clipboard code"><span class=".highlight nb">print</span><span class=".highlight p">(</span><span class=".highlight s2">"Hello Line Numbers!"</span><span class=".highlight p">)</span>
+</pre></div></div></td></tr></tbody></table></div>
+</div>
+</div>
+
 {{ heading("Mathjax") }}
 
 <div class="row">
@@ -406,4 +428,3 @@ <h4>Alerts</h4>
 <a href="http://daringfireball.net/projects/markdown/syntax">syntax</a> for more information.
 
 Please Note: An Otter Wiki is not using the official implementation. This might lead to small differences in the little things.
-

tests/test_renderer.py

@@ -81,6 +81,25 @@ def test_code():
     )
     assert pre_code is not None
     assert pre_code.text.startswith('non_existing_lexer')
+    # test highlight with line numbers
+    html, _ = render.markdown(
+        """```python=
+n = 2
+```"""
+    )
+    assert '<table class="highlighttable">' in html
+    table_code = BeautifulSoup(html, "html.parser").find(
+        'table', attrs={"class": "highlighttable"}
+    )
+    assert table_code is not None
+    td_linenos = table_code.find(
+        "td", attrs={"class": "linenos"}
+    )  # pyright: ignore
+    assert td_linenos is not None
+    assert td_linenos.text.startswith('1')
+    td_code = table_code.find("td", attrs={"class": "code"})  # pyright: ignore
+    assert td_code is not None
+    assert td_code.text.startswith('n = 2')
 
 
 def test_img():