[r6rs-discuss] Rationale issues

From: Mikael Tillenius <mti>
Date: Fri, 29 Jun 2007 08:46:07 +0200

Hi Thomas

You are still missing my main point. All of what you say below is
independet of the actual syntax. Earlier I gave you theses examples:

(com tillenius utils)
(uuid-f636e6e0-79df-4ac5-a8f4-98ca4d40d4f7 utils)

The naming scheme is (mostly) independent of the syntax used for the names.

Thomas Lord escribi?:
> In the URI-oriented view of the universe, there are lots of classes of
> applications, all of which should interpret URIs similarly. No two
> classes have to interpret URIs the same way but what defines each class
> of application is that it interprets URIs the same way as all the other
> members of the same class.
>
> We could speculate, for example, that perhaps all "conforming" Scheme
> language implementations should form an application class -- all
> interpret URIs (when used as library names) in "the same way" for some
> sense of "the same".
>
> In the URI view, the next distinction is between application classes
> which simply "pass thru" URIs vs. application classes that try to
> "resolve" those URIs -- to interpret them as names and retrieve some
> data or perform some function or ....
>
> "Pass thru" applications don't need to agree about much more than what
> characters a URI can contain and that two URIs are equal if and only if
> they are character-wise equal.
>
> "Resolving" applications need to parse URIs, in some sense. For
> starters, they need to agree about the meanings of URI scheme fields.
> In that very, very limited sense, there is a need for a central
> authority -- to manage scheme names for a given class of URI-resolving
> applications.
>
> But that's all the authority that's needed, if that authority is wielded
> well. In particular, one can define uri scheme's to have a meaning in
> which an "authority" is something that anyone can create, on their own,
> with no external authority. And then, as a consequence, anyone can
> allocate names within that authority.
>
> For example, an "authority" could be a standard UUID, or it could be a
> cryptographic signature. It could be the name of a hash function that
> explains how later parts of the URI should be interpreted. There are
> lots of ways to make naming authority non-rival.
>
> So, compare and contrast:
>
> Perl-like names for modules costs 10s to 100s of thousands of dollars
> per year (including unaccounted costs) to manage something like CPAN.
> The resulting authority service is monopolistic and imposes heavy
> transaction costs on allocating new names.

I didn't know that. Do you have a reference?

Btw what has this to do with how we want to represent Scheme library
names? Would the problem be solved if Perl started to use URIs? Could it
have been solved in the same way if CPAN had prefixed all its libraries
with CPAN::?

> URI-like names for Scheme modules would have a one-time cost of agreeing
> on the semantics of one or more URI scheme names in such a way as to
> permitted distributed, decentralized allocation of authority.

And the very same thing can be said about other syntaxes for names.

>> No, the main reason for using s-exps is that Scheme usually represents
>> things by s-exps.
>
>
> You mean like complex number constants, rational number constants,
> string constants, and other examples of compound values not written as
> parenthesized trees of more atomic values? What do you mean by
> "represents things by s-exps", exactly?

Last time I looked at a Scheme program it looked very much like a
sequence of s-exps. Thats approximatly what I mean.

/Mikael
Received on Fri Jun 29 2007 - 02:46:07 UTC