支持从模板生成解析器的模板引擎

Question

I am trying to make my templating engine for Python work backwards. That is, not only generate a document given a template and data, but also extract the data given a template and a document.

Given the page

<ul>
    <li><a href="/polls/456/">What is your name, stranger?</a></li>
</ul>

and the template

{% if latest_question_list %}
    <ul>
    {% for question in latest_question_list %}
        <li><a href="/polls/{{ question.id }}/">{{ question.text }}</a></li>
    {% endfor %}
    </ul>
{% else %}
    <p>No polls are available.</p>
{% endif %}

it will return a latest_question_list containing that one item.

What tool do you use to do this? It does not have to support Django templates, other templating engines will do just fine.

Answer 1

This breakthrough happened already. This is called bidirectional or invertible parsing. See it discussed here https://news.ycombinator.com/item?id=16392654

And this paper https://dl.acm.org/doi/10.1145/1863523.1863525 "Invertible syntax descriptions: unifying parsing and pretty printing"

And this Haskell library https://hackage.haskell.org/package/roundtrip among others

source: https://news.ycombinator.com/item?id=25319810