How to auto fold html tags?

Question

I am new to vim.

I have a HTML code with lots of <li></li> with its content that could span multiply lines like below:

<ol>
    <li>
        text
        text
    </li>
    <li>
        text
        text
    </li>
</ol>

When I apply :set foldmethod=syntax, vim does nothing on folding that tags. When I apply :set foldmethod=indent, vim apply code folding like this:

<ol>
    <li>
+---- 2 lines: text------
    </li>
    <li>
+---- 2 lines: text------
    </li>
</ol>

However, I intend to fold the code like when I use manual folding zfat:

<ol>
+---- 4 lines: <li>------
+---- 4 lines: <li>------
</ol>

So that it is more condensed and, at the same time, I know it is a listed items.

The problem is: how do I achieve this with auto folding?

Answer 1

You can achieve this using foldexpression. The best would be to create a function, that analyzes each line and returns an actual foldlevel. Here is a short example, that should get you started:

set fen fdm=expr fde=getline(v:lnum)=~#'<[^>]*>'?'a1':getline(v:lnum)=~#'</[^>]*>'?'s1':'='

Read the details at :h fold-expr (especially the special meaning of the return values for the evaluation of the expression.