dc showmanship (was: Need background on design of groff character classes)

"G. Branden Robinson" <[email protected]> Sat, 10 Jan 2026 16:57:28 -0600

Newsgroups	gmane.comp.printing.groff.general
Message-ID	<20260110225728.63ijsrklixsst24d@illithid>

I left out a footnote mark.  And since I'm here (and still waiting on
the GNU admins to issue my automated upload credentials[A]), I'll
indulge the Unix nerdery I forwent previously.

At 2026-01-10T15:43:05-0600, G. Branden Robinson wrote:
[...]
> The rationale for the `class` request was to facilitate groff usage by
> those composing documents in Chinese or Japanese.  To do so well means
> applying character flags to the characters used by thse languages'
> scripts.  Such characters are numerous.  Here's a sample.
> 
> tmac/zh.tmac:
>     .\" Chinese glyphs.
>     .class [CJKnormal] \
>       \[u4E00]-\[u9FFF]
> 
>     .cflags 512 \C'[CJKnormal]'
> 
> That's--let's see...
> 
> $ echo 'ibase=16;(FFF+1)*(9-5)+2*(FF+1)' | bc
> 16896
> 
> (Derivation available on request.)[7]
> 
> ...almost 17,000 characters affected for Chinese.
[...]
> [7] I admit, I was tempted to perform this calculation in dc(1)
>     instead.  But (a) I'm not au fait enough with it to casually toss
>     off an RPN version of that algebra--I'd need to check the man page
>     to see how to change the input base, which may be the 'i' command
>     but maybe not--and (b) this discussion is probably already
>     esoteric enough without such a gratuitous display.

Gratuitous display, complete with Thompsonesque gratuitous neglect of
spacing between operators:

$ echo '16i1 FFF+9 5-*FF 1+2*+p' | dc
16896

Took only a few tries.  The 'f' command stands for 'friendly'.

Regards,
Branden

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