{%- comment -%} This file can be used to fix the HTML produced by Jekyll for highlighted code with line numbers.

It works with `{% highlight some_language linenos %}…{% endhighlight %}` and with the Kramdown option to add line numbers to fenced code.

The implementation was derived from the workaround provided by Dmitry Hrabrov (DeXP) at github.com/penibelst/jekyll-compress-html/issues/71#issuecomment-188144901

EXPLANATION

The HTML produced by Rouge highlighting with lie numbers is of the form `code table`. Jekyll (<= 4.1.1) always wraps the highlighted HTML with `pre`. This wrapping is not only unnecessary, but also transforms the conforming HTML produced by Rouge to non-conforming HTML, which results in HTML validation error reports.

The fix removes the outer `pre` tags whenever they contain the pattern `<table class=“rouge-table”>`.

Apart from avoiding HTML validation errors, the fix allows the use of the [Jekyll layout for compressing HTML](jch.penibelst.de), which relies on `pre` tags not being nested, according to github.com/penibelst/jekyll-compress-html/issues/71#issuecomment-172069842

USAGE

(Any names can be used for `some_var` and `some_language`.)

{% capture some_var %} {% highlight some_language linenos %} Some code {% endhighlight %} {% endcapture %} {% include fix_linenos.html code=some_var %}

For code fences:

{% capture some_var %} “`some_language Some code “` {% endcapture %} {% assign some_var = some_var | markdownify %} {% include fix_linenos.html code=some_var %}

CAVEATS

The above does not work when `Some code` happens to contain the matched string `<table class=“rouge-table”>`.

The use of this file overwrites the variable `fix_linenos_code` with `nil`.

{%- endcomment -%}

{% assign fix_linenos_code = include.code %} {% if fix_linenos_code contains '<table class=“rouge-table”>' %}

{% assign fix_linenos_code = fix_linenos_code | replace: '<pre class="highlight">', '<pre>' %}
{% assign fix_linenos_code = fix_linenos_code | replace: "<pre><code", "<code" %}
{% assign fix_linenos_code = fix_linenos_code | replace: "</code></pre>", "</code>" %}

{% endif %} {{ fix_linenos_code }} {% assign fix_linenos_code = nil %}