Re: alternative for @U{} for older texinfo

[Gavin Smith]

On Mon, Jun 05, 2017 at 06:48:24PM +0000, Assaf Gordon wrote:
> Hi,
> 
> In gnu sed we recently expanded the manual with unicode
> content (e.g. '@U{FFFD}' commands in the texinfo file).
> 
> A user alerted us that this fails with older texinfo (5.2):
> https://lists.gnu.org/archive/html/sed-devel/2017-06/msg00002.html
> 
> Checking the logs I see that @U{} was added circa 2014,
> but it was only included in next official release (6.0)
> in 2015.
> 
> Do you have any suggestions for an alternative that
> would make it work (perhaps with degraded rendering)
> on older texinfo ?

You can check if the @U command is defined, and if not, define it
as a macro.  Like:

@ifset txicommandconditionals
@ifcommandnotdefined U
@macro U{a}
(Unicode character \a\)
@end macro
@end ifcommandnotdefined
@end ifset

@ifclear txicommandconditionals
@macro U{a}
(Unicode character \a\)
@end macro
@end ifclear

> I would like to avoid requiring a new texinfo to build sed,
> and but still like to include unicode characters in the manual.

You should distribute documentation generated from Texinfo source (i.e.  
Info files) so that people building your software don't need to have
Texinfo installed unless they edit the documentation sources.  This 
happens by default if you use Automake for your build system.  It is
different for people building from a source control repository that does
not have any of the generated files tracked.  I'm not sure if it's 
possible to avoid building the documentation even if the generated 
documentation is tracked - it would depend on the timestamps of the 
files, I suppose.