Re: Terminal problem? man formatting problem?

[Oliver Corff]

Hi Branden,

that is an interesting problem indeed. First I thought the angle
brackets (U+27E8, U+27E9) might be responsible, then I thought of trying
a different terminal emulator.

Et voilà, strange things happen.

I cannot use xterm, uxterm and Eterm on my system because of the high
screen resolution; those terminal windows appear as tiny stamps which do
not accept the Ctrl-+ resizing command.

So I tried gnome-terminal. In gnome-terminal, the same problem occurs,
too, but its behaviour is exactly the reverse of lxterm. If in lxterm a
URL is recognized correctly, in gnome-terminal the closing bracket is
read as part of the URL. If in lxterm the closing bracket is erroneously
taken as part of the URL, in gnome-terminal the URL correctly terminates
*before* the closing bracket.

That also suggests an issue with the terminal emulator.

Best regards,

Oliver.


On 24/04/2023 01:40, G. Branden Robinson wrote:
> Hi Oliver,
>
> At 2023-04-23T12:23:06+0200, Oliver Corff wrote:
> > I came across a minor case of misbehaviour when trying to open html
> > links in man pages.
> >
> > $ man 7 roff
> >
> > has a section "SEE ALSO" with a number of links to Internet sites.
> >
> > The first link under "History of Unix Manpages"
> > ⟨http://manpages.bsd.lv/history.html⟩ is ready for opening in the
> > browser once the mouse hovers over it but cannot be opened (404 file not
> > found) because the closing parenthesis ")" erroneously makes its way
> > into the link. See also the automated highlighting (on my terminal via
> > underlining). The underlined region includes the closing parenthesis
> > (but not the opening parenthesis).
> >
> > However, the next link (http://www.troff.org) is activated correctly.
> >
> > It seems to be that URLs ending in top-level domains are recognized
> > correctly whereas URS with a page element (.../history.html in the first
> > example) are not recognized correctly.
> >
> > Is this an issue of the terminal (I use lxterminal 0.4.0) of of the
> > formatting process chain?
> It can be.
>
> > The manpage source code is structurally identical in both cases:
> >
> > .\" on-screen URL highlighting includes closing parenthesis, Ctrl+Left
> > Click produces wrong URL (closing with ")")
> > .UR http://\:manpages.bsd.lv/\:history.html
> >
> > .\" on-screen URL highlighting does not include closing parenthesis,
> > Ctrl+Left Click produces correct URL
> > .UR http://\:www.troff.org
> That these hyperlink differently (with respect to trailing punctuation,
> apart from the obvious difference in URL content) suggests a problem
> with the terminal emulator...
>
> > PS: This machine runs groff 1.22.4,
> ...and that clinches it.  groff 1.22.4 did not attempt to tell the
> terminal emulator about hyperlinks; the emulator is inferring them, and
> getting it wrong.  (Not a surprise--it is an AI-hard problem to guess
> correctly.)
>
> > please forgive me if this is already fixed in the upcoming 1.23.0
> > release.
> I _hope_ that it is avoided, and that lxterminal does not try to
> pattern-match URLs in the terminal window when the character cells it
> would auto-hyperlink are already covered by an active OSC 8 escape
> sequence, but I can't promise that any given terminal emulator isn't
> buggy.
>
> This bug might be worth reporting to the lxterminal developers for the
> sake of people not yet using groff 1.23.0.  There'll be a few, since we
> haven't yet officially released.
>
> Regards,
> Branden

--
Dr. Oliver Corff
Wittelsbacherstr. 5A
10707 Berlin
G E R M A N Y
Tel.: +49-30-85727260
Mail: oliver.corff@email.de