Re: [Groff] Possible bug in -doc

[Ingo Schwarze]

Hi,

Carsten Kunze Heirloom wrote on Mon, Oct 03, 2016 at 12:31:02PM +0200:

> the problem in the document is the missing "-width" argument for .Bl.
> From groff_mdoc:
> 
> If a width is not specified for the tag list
> type, every time ?.It? is invoked, an attempt
> is made to determine an appropriate width.
> If the first argument to ?.It? is a callable
> macro, the default width for that macro will
> be used; otherwise, the default width of
> ?.No? is used.

Carsten's confusion shows that such behaviour isn't very user-friendly:
Even very experienced users, heck, even one of the main mdoc(7)
language hackers like Carsten, doesn't expect it, and i never noticed
that quirk either, not even after working on a major mdoc(7)
implementation for more than half a decade.

Even if we would want lists with non-uniform indentation, binding
that to the default widths of the first macros renders the feature
practically useless, and besides, i don't consider changing indentation
within a list typographically sound.  It will confuse manual readers
about as much as manual writers.  On top of that, neither Heirloom -
which is closest to the original 4.4BSD implementation - nor
mandoc(1) - which nowadays is the default mdoc(7) implementation
of all operating systems using the mdoc(7) language by default for
their mainuals - behave that way.  So it's also a portability
nuisance.

So i have submitted a patch to remove the feature and simply use a
reasonable, uniform default width for .Bl -tag without -width: 6n,
the same default width as for -hang:

  https://savannah.gnu.org/bugs/index.php?49272

Yours,
  Ingo