Re: [Chicken-users] basic Scheme question

[Shawn Rutledge]

On Fri, Oct 24, 2008 at 1:00 AM, Drake Wilson <address@hidden> wrote:
> Quoth Shawn Rutledge <address@hidden>, on 2008-10-23 23:54:03 -0700:
>> > Eval only sees the top-level environment.  It may be possible to use
>> > the environments egg to construct your own environment containing v.
>>
>> I thought of that, but also thought there must be a generic Scheme way
>> to do this.
>
> From someone with admittedly limited Scheme knowledge:
>
> The generic Scheme way wouldn't involve passing around quoted names and
> expecting them to retain their associations to the original lexical symbols
> at runtime, because they generally don't.
>
> The generic Scheme way would probably be to have a function encapsulate the
> idea of reading and writing the variable inside a "location" structure of
> some sort (pair of get+set function, likely) and then have the other function
> interact with that.

Right that's the usual pattern.  But I'm trying to call it remotely.

A client REPL opens an SSH connection to a server and starts a server
REPL.  Each of them evaluates what the other sends.  So if the server
sends
(let ([v (make-thing)])
   ...)
and the client evaluates it, then later the server wants to ask the
client to do any operation on the previously-created v, how can the
client now access the variable v, which exists only in that
environment created by "let"?  Just binding it to a top-level name
would pollute the namespace.  Having to bind the accessor is not so
bad, because the same accessor can be used to modify multiple remote
objects.