Re: easing access to bit vectors in the *roff language (was: Need background on design of groff character classes)

On 02.12.25 03:42, G. Branden Robinson wrote:

> Hi dvalin--,

> Off-topic, but I'm curious...where did this practice of suffixing user

> names with multiple hyphen-minuses come from?

Nary the foggiest, Branden - here in your post's quote is the first time I've seen it. It does not appear in the Bcc back here, of that post. Mystery == Total.

>

> At 2025-12-02T09:05:59+0000, dvalin--- via GNU roff typesetting system discussion wrote:

> > > .cflags 5 \[em]

...

> The idea I've been carrying around in my head looks somewhat like the

> "symbolic" form of the chmod(1) command.

>

> Some examples should get the idea across.

>

> .warn +delim

> .warn -char

> .warn =all

> .warn =w-delim

> .warn -w+syntax+reg+mac

>

> All of these are currently invalid syntax, so this should be a

> compatible extension.

That syntax hides the OR/AND in a most user-friendly fashion, I think. (And I'm inordinately fond of explicit human-readable syntax.) If there's less wrangling of a hand-knitted parsing engine, then that's so much more viable, I figure.

> [snip]

> > Here [in AVR assembly language] that implementational detail is

> > exposed, but in groff, implementation is best hidden, I figure.

>

> I agree.  GNU troff extrapolated from AT&T troff's `hy` request.

>

> ...which, itself, I'd like to shove into a dusty corner for legacy

> features.

> https://savannah.gnu.org/bugs/?55070

> > But ORing of named flags seems to be significantly more readable than

> > groff syntax. Neh?

>

> Even a bitwise or logical "or" is more of a demand upon the user than we

> need to make.  Why not plus, minus, and equals (in the assignment

> idiom[1])?

You've won my vote, though it's only that of a groff beginner trampling the edges of the maze, when time permits.

...

> [1] ...which I have problems with, since ":=" should be assignment and

>     "=" should be equality.  But the latter is a bit of brain damage C

>     programmers cherish even as they consider themselves far superior to

>     those who learned Microsoft BASIC, which does the same thing.

Put it down to C exposure, but "==" for equality test, and "=" seem nearly good enough. However, ":=" and "==" is a more secure combination, as omission of one "=" doesn't silently convert a test to an assignment. (Who has never had to debug that one?)

>     (At least Dartmouth BASIC [and ANSI Minimal BASIC] required `LET` to

>     make the context clear.  Also, did these snooty C hackers ever

>     notice that Ken Thompson himself wrote a BASIC interpreter?)

>

> https://www.tuhs.org/pipermail/tuhs/2021-December/024944.html

Haven't done that, but I did write a Z80 two-pass assembler, pre-millennium. (Don't tell anyone, but that was in BASIC.)

I've done a bit of lex & yacc - enough to get the hang of its limited debugging. A formal grammar is a stricture, but sanity-preserving in the long run. Your courage in facing an inherited hand-knitted if-but-maybe machine is awe-inspiring. I'd scream and run.

All power to your arm, and thanks for tolerating notions from those in the back row.

Regards,

Erik