[r6rs-discuss] [Formal] Requirement to detect circular lists

[Abdulaziz Ghuloum]

On Oct 3, 2006, at 5:38 AM, Dan Muresan wrote:

> So in the end, circular lists seem easier to create, more efficient,
> and potentially safer *for the periodic case*.

Just in case you haven't been paying attention, mutable pairs were
considered for removal from Scheme at some point in time.  The final
resolution was to keep them in their own (r6rs mutable-pairs) little
library that is not even imported by default when you import r6rs.

set-car! and set-cdr! are a thing from the past and I sure hope that
R6RS is the last Scheme standard to support them.  The benefits from
dropping mutable pairs far outweigh the alleged benefits of making
map, length, and friends accept circular lists.  Just my opinion.

Aziz,,,