[J3] [EXTERNAL] [BULK] Re: A couple more ideas for features

Van Snyder van.snyder at sbcglobal.net
Thu Apr 6 21:46:13 UTC 2023

On Thu, 2023-04-06 at 20:58 +0000, Brad Richardson via J3 wrote:
> Yeah, not saying it wouldn't work. Just from a language design point
> of view, if feels naked and a bit unintuitive as far as does it
> control the statements before or after? At least to a new comer to
> the language.

I remember the cover of the printed "man" pages for Unix in the 1970's
had "RTFM" in bold letters.
I don't think there would be any significant confusion if WHILE(...) at
the beginning of the construct were described, with the appropriate ISO
circumlocutions, as being tested before the construct block is
executed, and UNTIL(...) at the end of the construct were described as
being tested after the construct block is executed.
I can't think of a reason to have different constructs, one allowing
WHILE(...) at the beginning and only END DO at the end, and the other
allowing only DO at the beginning and UNTIL(...) at the end. One
construct that allows both "controls" would be simpler.
> On Thu, 2023-04-06 at 13:55 -0700, Van Snyder via J3 wrote:
> > On Thu, 2023-04-06 at 15:22 +0000, Brad Richardson via J3 wrote:
> > > I'm open to suggestions for exact syntax of the ending
> > > conditionals
> > 
> > At least one language, I don't remember which one, allowed
> > WHILE(...) at the beginning and UNTIL(...) at the end of the same
> > construct.
> > 
> > R1123 (loop-control) would remain unchanged.
> > 
> > R1134 (end-do-stmt) would have
> > 
> > or UNTIL ( scalar-logical-expr ) [ do-construct-name ]
> > 
> > added
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