Re: Locals revisited

On 27/03/2025 11:02 pm, albert@spenarnc.xs4all.nl wrote:

In article <87semzmwok.fsf@nightsong.com>,
Paul Rubin  <no.email@nospam.invalid> wrote:

albert@spenarnc.xs4all.nl writes:

In hindsight my locals definition is not convincing, because carnal
knowledge about the behaviour of the return stack is required.

>
It's ok if it's for a specific implementation.  But what I'm having
trouble seeing is how the locals get popped in case of an exception.

 
 
I showed it as an example of the pretty convincing usefulness
of CO. For this the example had to have to be portable.
 
A simpler example would be
\ Temporary set  some-rounding-mode  for the duration of this word.
: rounding set-rounding-mode CO truncate-mode set-rounding-mode ;
...

Actually it was that example which caused me to *not* go ahead
and implement ;: in the kernel despite a cost of only one header.
How many calls to 'rounding' will you encounter in an application?
My guess is one.  The usual example is HEX: but I already had (H.N)
that's more flexible.  For me at least locals was more credible but
again it fell into a range.  For a single use I'd do it manually;
for extensive use (where exceptions etc are likely) a proper locals
may be the only option.  OTOH such decision-making is exactly what
Forth has always been about.