Correctly ignore liquid template sections

[tmcw]

Our docs use {% highlight json %} style sections, and mdast / retext do not currently handle this, so code within these blocks causes false-positives.

[wooorm]

I’d say this should be implemented as a remark plugin. By default, mdast-util-to-nlcst (which is now wrapped in remark-retext) does not transform nodes without children to natural language nodes. This means that inlineCode, which has a value, is ignored when running, for example, retext-equality.

Could you link some examples of how and where these tags occur?

[tmcw]

Here's an example from our documentation:

Let’s make the neighborhood boundaries only show past zoom 15, but have the fill show all the time:

{% highlight scss %}
#neighborhoods {
  polygon-fill: #000; // Apply this at all zoom levels
  [zoom > 14]{ // Things to only apply past zoom 14
    line-color:#fff;
    line-width:0.5;
    line-opacity: 0.75
  }
}
{% endhighlight %}

This works almost exactly the same as our conditional formatting above, yet here we have written a rule for zoom levels only.

[wooorm]

Thanks for checking. Are those the only format? {% ... %}? I remember searching a while back for some formal grammar, I found lots of extensions (e.g., if, else, loops), are you using those at mapbox?

[tmcw]

Unfortunately liquid syntax is expansive: https://github.com/Shopify/liquid/wiki/Liquid-for-Designers

For the retext use case, it makes sense to ignore all liquid tags and the content in them, but for remark in general (if people are porting from Jekyll to something remark-based) it'd be useful for liquid-style highlight blocks to be interpreted the same way as fenced code blocks.

[wooorm]

Oh, darn...

Would it maybe be better to preprocess the file before passing it to remark? This depends on whether those tags can produce markdown and thus HTML: {{ '*' }}foo{{ '*' }} to <em>foo</em>, when compiling to HTML, or is this not the case?

[tmcw]

Yep, for my usecase censoring liquid tags will do just fine, and the general case is probably way too much work for benefit. I'll do that, it's probably just a few regexps away :)

[tmcw]

It isn't pretty, but https://github.com/mapbox/retext-mapbox-standard/blob/master/lib/strip_liquid.js does the trick.