[Larceny-users] ERR5RS Default Record Printer

[William D Clinger]

Ray Racine asked:
> Is (record-updater (record-type-descriptor thread-rtd) 'printer) ...)
> valid ERR5RS or shall it be considered as a Larceny and therefore
> non-portable extension?

That's Larceny-specific and therefore non-portable.
There are likely to be some implementations of ERR5RS
that implement ERR5RS records as R6RS records, which
means the record printer may not be customizable.

(Some implementations of R6RS records may support a
similar extension, but portable code can't rely on
any extension at all, and certainly can't rely on
extensions being compatible with Larceny's.)

Will