[r6rs-discuss] [Formal] SRFI-39 should be made an R6RS library

[William D Clinger]

I am posting this as an individual member of the Scheme
community.  I am not speaking for the R6RS editors, and
this message should not be confused with the editors'
eventual formal response.

Kent Dybvig quoting Mike Sperber:
> > (Pure deep binding doesn't have this problem.)
> 
> Deep binding has undesirable overhead of its own, as I'm sure you are
> aware, i.e., reference cost proportional to the number of current dynamic
> bindings.

And deep binding can, of course, be cached on a per-thread
basis, which does not, of course, change the worst-case
behavior, which I could go on about, but...

I think you guys have reached the point where you are
arguing over minutia.  In particular, the performance
issues appear miniscule compared to many other costs
that are being introduced by the draft R6RS (e.g. the
as-yet-unknown-but-quite-possibly-significant cost of
letrec* semantics for internal and library definitions),
and the semantic issues appear miniscule considering
the fact that Scheme doesn't even have a portable memory
model for multi-threaded execution.

Will