+[[!template id=gitbranch branch=jon/table_headerblock author="[[Jon]]"]]
+[[!tag reviewed]]
+
It would be great if it were possible to support multi-row table headers in the [[plugins/table]] plugin, so you could do e.g.
\[[!table header="""
-- [[Jon]]
[[!tag wishlist patch]]
+
+> This seems like weird overloading of the header parameter - it's
+> table data, except when it isn't.
+
+> > My first cut (now rebased out of existence I think) introduced a
+> > new "headerblock" parameter, but trying to clearly document the
+> > interaction of data/headerblock/header parameters was too awkward. -- [[Jon]]
+
+> Perhaps
+> something like this would be easier to use in practice?
+> (and also more featureful :-) )
+>
+> \[[!table header="2 rows 1 column" data="""
+> Name | Platform ||
+> | Windows | Mac | Linux
+> ikiwiki | no | yes | yes
+> Starcraft | yes | yes | via Wine
+> """]]
+
+> > Thanks for your prompt feedback!
+> >
+> > This would probably be good, yes, and having mixed row/column headers is
+> > definitely a nice-to-have. I don't relish the prospect of writing the parser
+> > but I see you've made a stab already...
+> >
+> > One thing you'd lose, but it's debatable whether this is valuable, would be
+> > to have the header defined in the directive, and the remaining table data
+> > declared in an external CSV. -- [[Jon]]
+
+> intended to be rendered like
+>
+> <table>
+> <tr><th>Name</th><th colspan=2>Platform</th>
+> <tr><th></th><th>Windows</th><th>Mac</th><th>Linux</th></tr>
+> <tr><th>ikiwiki</th><td>no</td><td>yes</td><td>yes</td></tr>
+> <tr><th>Starcraft</th><td>yes</td><td>yes</td><td>via Wine</td></tr>
+> </table>
+>
+> (Deliberately switching to plain-text to make it more obvious
+> what's a `<th>` and what's `<td>`.)
+>
+> Vague pseudocode for parsing `headers`
+> (possibly even valid Perl, I'm not sure):
+>
+> my ($header_rows, $header_cols);
+> while ($header =~ s/(\d*)\W*(\w+)//) {
+> my $n = ($1 or 0);
+> my $what = $2;
+> if ($what =~ m/rows?/) {
+> $header_rows = $n;
+> }
+> elif ($what =~ m/col(?:umn)?s?/) {
+> $header_cols = $n;
+> }
+> }
+>
+> and it would even be fairly easy to extend to support
+> `(first|last|)\W*(\d*)\W*(\w+)` later, e.g.
+> `header="1 row, first 2 cols, last column"`.
+>
+> --[[smcv]]
+
+> > To be clear I think your suggestion is a good one, but my hack has
+> > addressed my immediate need so it's the one I'm deploying at $ork for the
+> > time being. I'm unlikely to have time to implement this solution in the
+> > near future. -- [[Jon]]
+
+----
+
+I'd quite like to revisit this if that's ok. I'm still carrying a fork of
+table.pm locally to add this feature as I find it so useful. The main objection
+you made back in 2014 seems to be overloading the header= parameter, and I agree
+that this is not ideal. So I'm happy to resubmit this with an alternative parameter
+name for the new purpose. But I balked at the idea of implementing something like
+an NLP processor to define the header range. And I must stress how useful it is in
+practise to separate out the header definition from the data: quite often I don't
+want headers in my CSV files at all, for example, so I can perform rudimentary analysis
+on them with command line tools without having to factor in a header line (how many
+records? = `wc -l`; sorting on fields simply with `sort -k` etc.). Having them
+separate means I can have machine-generated or manipulated CSV files of data and then
+use ikiwiki to mark them up for human reading, but change or regenerate the data quickly
+and easily underneath.
+
+I'd appreciate your take on the above suggestions [[smcv]] before I roll my sleeves up.
+Thanks! — [[Jon]] (2018-09-24)
+
+> I continue to think that the `header` parameter shouldn't be sometimes a
+> description of which parts of the table are header, and sometimes the header
+> data itself; so if you want an inline header, it should indeed have a
+> distinct name.
+>
+> If you can think of a good name for the new parameter, and can document it
+> reasonably clearly, then I would be OK with having a separate parameter that
+> is the externally-provided header. I don't know what the right name for that
+> parameter would be: `headercontent` or `headerblock` is unwieldy but I can't
+> think of anything better.
+>
+> It would maybe simplify things to make it mutually exclusive with `header`,
+> but then you wouldn't be able to express things like "the first column of my
+> CSV is a header, the first row is just an ordinary row, and please add
+> this literal header row to the top".
+>
+> It might help to write the documentation and/or tests first, and then
+> implement it afterwards, when you have an "API" you're happy with.
+>
+> Corner cases:
+>
+> How would it work if you want to add a literal header column on the left
+> rather than adding a literal header row on the top? If you add both, what
+> happens at the top left corner?
+>
+> Is it necessary to be able to add header columns on the right (for RTL
+> languages?), or header rows (footer rows, I suppose) on the bottom?
+>
+> --[[smcv]]