Add html headings to the first cell of each row

[nathanj3]

First -- thanks for making such a great package. My unit uses it a lot for our report writing.

With the revisions to ADA Title II in the U.S., all our reports (actually, all online content generated by a public university) are now required to meet WCAG 2.1 AA requirements, which changes the way we deal with table headings.

Currently, for "simple" tables, the current heading structure works. But with the level of detail in most of our tables, it's preferable to be able to have both a heading row at the top, and a heading cell within every row, i.e.:

<table>
  <caption>Delivery slots:</caption>
  <tr>
    <td scope ="col">Time slot</th>
    <th scope="col">Monday</th>
    <th scope="col">Tuesday</th>
    <th scope="col">Wednesday</th>
  </tr>
  <tr>
    <th scope="row">09:00 – 11:00</th>
    <td>Closed</td>
    <td>Closed</td>
    <td>Closed</td>
  </tr>
  [...]

(Example from W3)¹

Would it be possible to add add_header_col, either as an arg to an existing function, or as a separate function that works with the %>% pipe? The 'scope' tag would be nice, but even without it, the option to change the first cell in each row from <td> to <th> would solve the problem for most cases.

Currently, we're running a post-processing Python/BeautifulSoup script that edits the HTML report after it's been knitted, but it would be amazing to have the <th> tags generated in the report itself.

Footnotes

1. I added "Time slot" to their example because it's impossible to leave the top left cell empty in an R data frame or matrix (plus it goes against the tidy data philosophy and such). ↩