RE: Seeking advice on writing a "line-based" major mode

[Drew Adams]

Thanks for providing more info.

> 1. EWOC has built-in support for checking which entry the point is
> on. I didn't find anything like that in tabulated-list-mode.

Not sure what you mean, but that sounds like `tabulated-list-get-entry':

  Return the Tabulated List entry at POS. ... defaults to point.

or depending on what you mean, perhaps `tabulated-list-get-id':

  Return the entry ID of the Tabulated List entry at POS.
  ... defaults to point.

> 2. EWOC seems to be more flexible wrt the format of the entries.  In
> my use case, each entry is a large-ish alist, converted from json by
> json-read, and most of the entries in it should not show up at all.

So you want to show only some of each alist entry.

  `tabulated-list-print' calls the printer function specified by
  `tabulated-list-printer', once for each entry.  The default
  printer is `tabulated-list-print-entry', but a mode that keeps
  data in an ewoc may instead specify a printer function (e.g., one
  that calls `ewoc-enter-last'), with `tabulated-list-print-entry'
  as the ewoc pretty-printer.

and `tabulated-list-entries':

  If a list, each element has the form (ID [DESC1 ... DESCN])
  
or it can be a function that returns such a list.

In your case, one of the DESC would presumably be your alist value,
formatted to show only some of it.

I know very little about EWOC, but so far I don't really see what
more it offers here.  (Not that I need to.  The info you provide is
anyway helpful.) 

> I's also want to be able to do sorting based on more than one
> column

Same here.  That would be a useful addition to `tabulated-list-mode'.

> So basically, while the differences are significant, both tools
> could do the job - it just happens that EWOC has the parts I didn't
> want to code myself already done.

Understood (though it's not clear to me what those parts are).

> BTW, be assured that when I finish my tool (or at least get to
> a production-ready beta, which seems quite close), I'll write a blog
> post (or a few) about it, and put the code on the net somewhere.

Thx.