[r6rs-discuss] [Formal] Record layers are not orthogonal.

[David Van Horn]

Abdulaziz Ghuloum wrote:
> On Nov 16, 2006, at 12:50 AM, David Van Horn wrote:
>> I don't understand the problem with these syntactic layers being
>> optional.  If they are compelling, implementations will support them.
>> If not, why should they be included in the language standard?
> 
> If I may add that if they can be implemented portably, you wouldn't need
> implementation support to use them.  You can just import and hack away (in
> theory at least).

By support, I meant something like, make the library available to users, 
include documentation, etc.  In any case, it seems irrelevant.

> I see SRFIs as a way to ask implementors to support libraries that cannot
> be expressed using R6RS.  Such libraries include FFI, networking, 
> guardians,
> etc.  Libraries that can be expressed directly using R6RS such as regular
> expressions, XML parsers, adventure games, etc. are better distributed via
> some other distribution mechanism (like PlaneT) since they do not need the
> SRFI process.  Implementors can support popular libraries natively if they
> wish.

I agree that SRFIs are well suited for requesting features that cannot 
be expressed in R6RS.  But I also believe SRFIs serve a purpose for 
describing libraries that can be well-implemented portably but are 
beyond the scope of the language definition.  For example, a 
comprehensive list library is a good SRFI candidate.  The community 
benefits by having a consistent, complete, and portable library.  Should 
this be part of R6RS?  No-- R6RS should give us the means for writing 
such a library, not the library itself.  Should this be a package 
distributed by some individual or group?  No-- the community benefits 
from having a unified library with a clear immutable specification that 
has undergone public review.  Other SRFIs of this kind would include 
libraries for things like streams, comprehensions, enumerated sets, 
strings, etc, etc.  I am not convinced, but I believe it at least 
plausible that a syntax for records could fall into this category.

David