Re: r6rs libraries

[Julian Graham]

Hi Andy,

Thanks so much for helping me parse!


> I think you're right, yes. I think that the approach that you describe
> has been called "Implicit phasing" by Ghuloum and Dybvig. They have a
> paper about it, "Implicit phasing in R6RS libraries" -- but I haven't
> been able to find it freely on the web. ACM fail.

Oooh -- if you do find it, let me know.  That sounds interesting.


> I could not find the quote that you referred to here -- I think what I
> can tell (from 7.2):

(Yes, that was the bit I was referring to.  Sorry about that.)

One thing that occurred to me, though, while I was brooding on this,
is the case in which you've got two bindings that share the same name
that are both imported (from different libraries) into library foo --
one's a syntax transformer used to expand library foo, the other's a
function used by library foo at runtime.  R6RS seems designed to
address cases like this so that they work out, you know, hygienically.
 And I think Guile's module system can handle this as well, though it
may require some slightly weird designs.

E.g., one thing I was thinking of trying was mapping an R6RS library
onto *two* generated Guile modules: One to represent the expansion
environment, and one to represent the environment of the expanded
library in which the library bindings and top-level expressions are
actually evaluated (I guess this is the same as the runtime
environment?).  The first module's imports would include bindings
required for expansion; the second's would include the stuff for
runtime.


> I don't think you're missing anything big, no. I hadn't fully poked into
> these implementations -- if it is easier just to build something on top
> of Guile's modules than to retrofit guile's modules into one of their
> implementations, then that's all the better, right?

Strongly agree.


Regards,
Julian