On 26 Jan 2025, at 19:35, Wolfgang Corcoran-Mathe <xxxxxx@sigwinch.xyz> wrote:

> On 2025-01-25 17:41 -0500, Antero Mejr wrote:
>> Is there an intended use case that necessitates the inclusion for the
>> :|| syntax? The SRFI says that most implementations do not offer a
>> syntax. I think ":||" will be a bit annoying to implement in a reader:
>> it isn't prefixed by "#", and ":" is a valid character in identifiers.
>
> Uninterned symbols must have a datum notation if they're to be usable
> with datum->syntax. That's necessary, I believe, to implement the kind
> of macros Daphne discusses in her message (at least, in the way she
> implements them).

I think the Right Thing in the absence of all other precedent would be to require uninterned symbols to print as #< unreadable objects, because read/write invariance under the datum equivalence predicate, equal?, can not be preserved, unlike for all other datums.

However, since so many implementations already print gensyms either as if they were regular symbols or with some other lexical syntax, probably it is the Right Thing considering precedent to try to settle a standard lexical syntax.

Not having lexical syntax would indeed require adjusting the specification of procedures which take specifically a datum as argument, hmm. I’m not sure there are too many of these. Datum->syntax might in fact be the only one.

Daphne