[bug #52526] [gn]roff: no warning or error when a line ends with "\{"

[G. Branden Robinson]

Follow-up Comment #4, bug #52526 (project groff):

[comment #3 comment #3:]

> > Is this a manifestation of bug #45502?
> 
> I'm going to say no?  According to what we see there, AT&T troff has an
extra-special syntax case where if there are no tokens (or spaces only?) after
the conditional expression of an .if or .ie request before a newline, then the
newline is ignored.
> 
> This is a hypothesis.  I should fire SIMH back up and see.  Or read the
V7/Heirloom source.

The above turns to be wrong--in fact, it seems to be backwards. Heirloom
Doctools troff and V7 Unix troff both produce the same output for the
following input.


$ cat if.roff 
.if \nb
one
.nr a 1
.if !\na
two
.br
.pl \n(nlu


That output being


one two


This is what I would have expected given the documentation I just freakin'
_wrote_ not too long ago.

Imagine, then, my shock when groff itself didn't behave this way.


$ groff -Tutf8 if.roff  | od -c
0000000


And that's groff 1.22.4, not something I horked up on Git HEAD.

I'm thinking the above is indeed a manifestation of bug #45502.

I think Carsten was right, but it was hard for me to see that because he
characterized the syntax used as "wrong".  It wasn't wrong, just degenerate. 
He also, I feel, inaccurately characterized the specification of the control
structure requests; in "traditional" troff, whitespace is optional between
both the request and the conditional expression, _and_ the conditional
expression and the "body" of the if/ie.

On V7 Unix we see:


$ nroff
.nra 2
.if\na=2foobar
foobar
[65 blank lines]


Anyway, I guess the balance of the discussion should move back to bug #45502.



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