[Chicken-users] R6RS immutable pair

[Kon Lovett]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Hi Group,

R6RS appears straightforward for Chicken (except for a lot of typing,  
the nagging read/write invariance of flonums, the undecided details  
of 'library', & whatever I forgot - remind please).

Anybody want to way in on the proposed immutability of pairs? FWIW, I  
am ambivalent. My gut says NO but my heart says yes. This is the most  
serious suggested change, IMHO. It doesn't just "break some existing  
programs", it breaks with 50 years of lisp tradition.

In Chicken 'set-c*r' is a common operator. Should pairs be immutable  
something must replace them. I don't buy the suggestion of records or  
vectors as a replacement, too heavy.

My naive thought is 'list' should be disjoint from 'pair', although  
how to achieve this escapes me. The message I get from section 5 is  
'proper list' is a distinct type from 'circular list' & 'improper  
list'. I agree, but ...

- - Capt Picard: "Make it so, Number One." (wish it were that easy.)

Best Wishes,
Kon


-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.3 (Darwin)

iEYEARECAAYFAkSoABkACgkQJJNoeGe+5O5efACfRiUqQ0IN4M5QfRRL6AZD6Xws
QBEAn1VlVeKAWaQx8l63EGM9xZpQ/w9Y
=iBHz
-----END PGP SIGNATURE-----