[TUHS] Curly braces: An evolution of UNIX and C

[Thalia Archibald via TUHS]

On Wednesday, May 20th, 2026 at 11:37, Phil Budne wrote:
> For my two fractional monetary units (the US no longer mints
> new cent pieces):
>
> The trigraphs and later digraphs are a footnote, and don't deserve to
> be featured/discussed up at the top.

Of course. But this is all footnotes.

> I think historical BCPL, using $( and $) is the place to start, moving
> on to PDP-7 B.
>
> In fact, I think I'd find a strictly chronological presentation (early
> structs before UNIX 4th edition terminal driver) would be clearest.

I presented it working backwards from our modern assumptions. It's related
periods progressing forwards, then jumping back to the next period. The B to NB
to C section really needed to be forwards.

I wrote this piece fairly linearly in one (long) sitting and it follows my
research direction. I agree that it would be better chronological.

> ISTR the UNIX terminal driver also allowed entering displaying both
> upper and lower case via escaping, tho the "upper case" versions of
> the (curly) braces are the (square) brackets.

I should have added it, but I decided against it, since UNIX style was to use
lowercase and I didn't want to change it to "Hello, world!". It would work with
the ed session.

> In the B section, instead of
> > The 1973 B language tutorial for the H6070 had the first-ever “hello, world” program
>
> I'd say that it was the first known/documented example of hello world.
>
> https://research.swtch.com/b-lang
> From 2008 says
> > Brian Kernighan's 1973 B tutorial contains what is probably the very first “hello, world” program.
>
> which makes the same conclustion but hedges whether it was in fact THE FIRST.

Good point.

Thalia