Hi John,
At 2024-08-09T16:41:11+1000, John Gardner wrote:
> [I wrote:]
> > All of the terminal output devices groff supports lack overstriking
> > support.
>
> Whoops. I forgot that what I was seeing in less(1) was actually duped
I don't think it was duped. It was being clever. There is lots of
cleverness in less(1). Some of it makes me cringe.
> using an underline effect. On that note, am I right to assume that
> \fI+\fP0 is equally implausible by virtue of terminals diverging
> wildly in their italicisation support? (Underlining, obliquity,
> ignoring the effect outright, etc).
Not equally implausible. Most terminals one encounters support enough
of what ECMA-48 calls "graphic renditions" that, _generally_, in your
exhibit the '+' and the '0' will appear in visually distinguishable
styles. But little beyond that can be said: they might be different
colors, the plus sign might be in standout (reverse video) mode, it
might be underlined, and so on.
And a document author, particularly of a man page, does _not_ want to
rely solely on text style changes to communicate meaning. Such things
go away when people do unspeakable things like copying and pasting
chunks of man pages into email messages, losing all formatting. As a
rule it's prudent to ensure that your meaning is adequately conveyed
when the text is read aloud. That's a laudable practice in all writing.
(I assume that Slack and Discord clients support "rich text", and
eagerly convert each word of styled text into 100kiB of CSS-ful HTML
overhead.[1])
> That reminds me (and I'm being dead serious here), if anybody knows
> where a Model 37 can be acquired in 2024, *please* let me know. (I
> spent all arvo yesterday searching… seriously).
I read somewhere recently, possibly on the TUHS or COFF lists, that
Model 33 machines experienced an active and deliberate period of
junking. And as far as I know Model 37s were not very common outside of
Bell Labs, which partly explains why such devices were known mainly as
"ASR 33"s, a misnomer in multiple respects.[2] Who needs a Greek box,
anyway?
Good luck. If you are ever successful I may send you a draft notice
enlisting you in the improvement of groff's hardcopy terminal support.
> Why stop there? Such a conditional could match against a named field
> (and optional value) in an output driver description (DESC) file,
> whether it's recognised by Groff or not. Something like:
>
> .if T unicode \{
> .if T res > 50 \{
>
> I mean, if we're gonna extend the syntax to include something this
> niche, we may as well go all the way.
Much of the machinery is already in place for this.
Numeric expressions are already valid conditional expressions, so all
we'd need here is a syntax for interpolating an output device parameter.
As it happens, `\T` is _not_ yet taken. So I'd write your thought
experiment as follows.
.if '\?\T"unicode"\?'\?1\?' .tm hooray! we've got Unicode!
.if \T'res'>50 .tm output device has good resolution
Except in AT&T troff compatibility mode, switching up delimiters when
nesting them is not necessary, but doing so can be kind to humans.
And yes, there's a story behind all those wacky `\?` things.
---snip---
5.23.1 Operators in Conditionals
--------------------------------
In 'if', 'ie', and 'while' requests, in addition to the numeric
expressions described in *note Numeric Expressions::, several Boolean
operators are available; the members of this expanded class are termed
"conditional expressions".
[...]
If the first argument to an 'if', 'ie', or 'while' request begins
with a non-alphanumeric character apart from '!' (see below), it
performs an output comparison test. (2) (*note Operators in
Conditionals-Footnote-2::)
'XXX'YYY'
True if formatting the comparands XXX and YYY produces the same
output commands. The delimiter need not be a neutral apostrophe:
the output comparison operator accepts the same delimiters as most
escape sequences; see *note Delimiters::. This "output comparison
operator" formats XXX and YYY in separate scratch buffers; after
the comparison, the resulting data are discarded.
[...]
Surround the comparands with '\?' to avoid formatting them; this
causes them to be compared character by character, as with string
comparisons in other programming languages.
.ie "\?|\?"\?\fR|\fP\?" true
.el false
=> false
Since GNU 'troff' reads comparands protected with '\?' in copy mode
(*note Copy Mode::), they need not even be valid 'groff' syntax.
The escape character is still lexically recognized, however, and
consumes the next character.
.ds a \[
.ds b \[
.if '\?\*a\?'\?\*b\?' a and b equivalent
.if '\?\\?'\?\\?' backslashes equivalent
=> a and b equivalent
---end snip---
(Anyone who hates the word "comparand" can blame me.)
I don't know if we'd want to support a `\T[]` syntax as well. Maybe.
Regards,
Branden
[1] I am informed that these technologies, along with GitHub Merge
Requests, are the only means of collaboration that developers need
take seriously these days. Email is for old men attempting to
thwart all progress.
https://salsa.debian.org/dep-team/deps/-/merge_requests/8
One can almost see Mark Shuttleworth, or someone of identical
properties,[3] holding the control bar of a marionette.
[2] "Teletype" was (is?) a trademark, and thus should not be used as a
noun. "ASR" was not a model identifier, but an option, and that
option specifically designated a unit _without a keyboard_. One is
not going to emulate Thompson and Ritchie that way. What people
_mean_ when uttering the slovenly, Eric-Raymondesque "ASR-33
teletype" locution is closer to:
"Western Electric (or Teletype Corporation) Model 33 (or 37) KSR
(teleprinter or teletypewriter)"
...where "KSR" means "keyboard send and receive".
There are many ways to abbreviate that lengthy identifer; "ASR-33
teletype" is a poor one.
I don't claim to know whether the vertically integrated structure of
AT&T, Western Electric, and the Teletype Corporation was stable
throughout the lifetime of these products. Regulated monopolies
lead to fascinating (and/or dismaying) ownership structures.[4]
[3] Like Luca Bocassi plus one billion dollars?
[4] https://coppolacomment.substack.com/p/thames-water-and-its-dividends
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