------- Forwarded message -------
From: "John Cowan" <[email protected]>
To: "Aaron W. Hsu" <[email protected]>
Cc: "John Cowan" <[email protected]>
Subject: Re: [r6rs-discuss] Proposed features for small Scheme, part 1: a  
stake in the ground
Date: Sat, 05 Sep 2009 21:37:15 -0400

Aaron W. Hsu scripsit:

> to emphasize backwards compatibility. There is no reason to break
> compatibility with older systems in Scheme, since not that much has  
> really
> changed.

I've backed off the claim that R4RS is an obsolete standard, but I stick
with the claim that R4RS-only implementations are not being actively
developed: I await counterexamples other than Stalin.

> We've added things, sure, but it should still be possible to
> express that a program is R4RS instead of R5RS, IMO.

There's no way to do that now, except with ad hoc metadata.

> Using the right set of modular libraries, I bet we could also allow
> differing semantics to some extent for backwards compatibility sake,
> though I don't see any reason to do this since nearly everything is
> R5RS now, and there are precious few programs left in the Scheme world
> relying on, say, nil == #f.

Just so.  Even R4RS doesn't actually allow that, it just says some
implementations break the rules.


-- 
Of all tyrannies, a tyranny sincerely exercised for the good of its  
victims may be the most oppressive. -- C. S. Lewis

_______________________________________________
r6rs-discuss mailing list
[email protected]
http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss

Reply via email to