Re: notice: intent to kill off 'Df'

[John Gardner]

Hi Branden,

Support for 'f' may disappear in the next release, producing an error
> diagnostic regarding an unrecognized command.
>

This doesn't sit right with me. Removing an obsolete feature to encourage
adoption of a newer one runs counter to Groff's normative handling of
legacy features—a manual that's formatted correctly and consistently for
the past 20 years will logically be expected to continue doing so. I'm
aware that \D'f…' isn't supported by AT&T Troff (although it *is* supported
by SQTroff), but that strikes me as a weak argument to justify the
feature's removal.

Assuming there's no practical benefit to removing \D'f…' outright, I
instead suggest documenting it as an explicitly obsolete feature, similar
to how the *"Legacy command(s)"* section in groff_out(5) documents the old
"jump right *dd*u and print char *c**"* method for outputting text. The
section makes it crystal clear to readers that this syntax is supported for
backwards compatibility only, and suggests modern alternatives they should
be using instead. \D'f…' should do likewise, IMO.

Regards,
— John

On Thu, 29 Jun 2023 at 04:13, G. Branden Robinson <
g.branden.robinson@gmail.com> wrote:

> I admit this may be a bit rash with only 20 years of warning.
>
> If anyone's wondering, the 'Df' drawing command is not documented in
> CSTR #54.
>
> Also see <https://savannah.gnu.org/bugs/?64353>.
>
> This if for groff 1.24--but to give more notice, if there is to be a
> groff 1.23.1, I propose cherry-picking it onto a 1.23-stable branch or
> similar.
>
> Diff attached.  Comments welcome.
>
> troff
> -----
>
> o GNU troff now issues an error diagnostic when the 'f' drawing command
>   is used (in a `\D'f 500'` escape sequence, for example).  This drawing
>   command was declared obsolete in this NEWS file 20 years ago as part
>   of the groff 1.19 release.  Users of this escape sequence will want to
>   migrate to the `Fg` drawing command or use higher level language
>   features, like the `defcolor` and `fcolor` requests, and the `\M`
>   escape sequence, for setting a grayscale fill color for geometric
>   objects.  Support for 'f' may disappear in the next release.
>
> Output drivers
> --------------
>
> o Output drivers now issue a warning diagnostic when the 'f' drawing
>   command is used (`Df 500 0`, for example).  This drawing
>   command was declared obsolete in this NEWS file 20 years ago as part
>   of the groff 1.19 release.  Users of this escape sequence will want to
>   migrate to the `Fg` drawing command to set a grayscale fill color for
>   geometric objects.  Support for 'f' may disappear in the next release,
>   producing an error diagnostic regarding an unrecognized command.
>
> Regards,
> Branden
>