optional documentation formats and targets?

[Karl Berry]

(Sorry for the wide distribution, but I wasn't sure who would be
affected, and wanted to seek advice.)

Eric Blake from m4 (thanks Eric) asked about the coding standards:

    And since dvi et. al are not invoked by 'make all', it is not
    obvious whether 'make install-dvi' should depend on dvi or be a
    no-op if the user didn't first do 'make dvi'.

I am inclined to say that install-DOCFMT should depend on DOCFMT.  Does
that sound ok?  ... Analogous to `install' depending on `all'.  (Doesn't
it?)  It seems that latter dependency is only implicitly stated in the
standards, but maybe that is ok.


Eric also pointed out a possible discrepancy in the coding standards
saying that not all documentation formats need be supported:

    http://www.gnu.org/prep/standards/standards.html#Directory-Variables
    states that for htmldir, dvidir, pdfdir, psdir, "(It is not required to
    support documentation in all these formats.)".  

I am not sure why that caveat is present.  Does anyone see a problem
with simply removing the parenthetical?  I think in practice it will not
make a difference; there is no suggestion that these formats should be
included in distributions, or built by default, or anything like that.

One more related point from Eric:

    dvi, html, pdf, and ps are also listed as standard make targets, but
    with a caveat "Generate documentation files in the given format, if
    possible."

In this case, I think the caveat is ok.  I can imagine some (unusual)
manual not making sense in, say, DVI format, because it makes extensive
use of hyperlinks or something.


Thoughts?

Thanks,
Karl