[racket] racket/place seems to be incompatible with DrRacket

From: Kevin Tew (tewk at cs.utah.edu)
Date: Tue Aug 30 16:27:08 EDT 2011

I completely forgot the concept that some modules exist only bound to a 
Your example helped me understand the problem better.
My analysis of the problem and and suggested solution were way off.
So I apologize.

On 08/30/2011 01:46 PM, Robby Findler wrote:
> DrRacket is naming them. They are named 'anonymous-module and are put
> into the current-namespace. (Changing the module-name-resolver in that
> manner seems like a bad idea to me -- and modules can exist just
> attached to the namespace like that. For example, '#%place is one such
> module that you are familiar with.)
> One simple-to-fix problem with 'place' was that it was not correctly
> handling symbols as module names. I've pushed a fix. (You should
> probably look at the commit message for some other, minor comments on
> the code.)
Thanks, your other changes were insightful too.  I learned a few things.
> One harder-to-fix problem (at least for me) is that dynamic-place does
> not handle such modules. I don't know if the fix is to signal an error
> or to improve how places are started, but here is an example of how
> dynamic-place is being called in this case.
I talked with Matthew and I am going to add code that detects symbol 
module names
and throws an error before the new place is ever created.
> #lang racket
> (define ns (make-base-namespace))
> (parameterize ([current-namespace ns])
>    (eval '(module m racket/base (define (f pc) (printf "hi\n"))))
>    (eval '(require 'm))
>    (eval '(require racket/place))
>    (eval '(dynamic-place ''m 'f)))
> This produces this error:
>     dynamic-require: unknown module: 'm
> which should be unsurprising to you, because the newly created place
> doesn't get the module 'm.
> A third problem: the error is printed to the original stdout of
> DrRacket (which is probably why you and David Mitchell didn't see it).
> It would be better if there were some error handling code that
> transmitted the exception record (or perhaps just the message field)
> back to the original place for rendering there. I'm thinking
> specifically in the case that the initial require fails. (I think I've
> mentioned this before so if there's some reason I'm missing that keeps
> this from being changed, please let me know.)
I'm going to add a feature that allows the user to specify file ports or 
racket pipes for a new place's standard in, out, and err ports.
In the Drracket case, I'll detect that that the current-error-port isn't 
a file port or racket pipe and set up an IO pump that
pumps a place's standard IO ports into the current Drracket ones.

I think that should provide good error messages and solve the confusion 
David Mitchell experienced


> Robby
> On Tue, Aug 30, 2011 at 1:32 PM, Kevin Tew<tewk at cs.utah.edu>  wrote:
>> Place are spawned by dynamically requiring a module.
>> It appears that an unsaved module in drracket gets the name
>> "anonymous-module" and the module-name-resolver doesn't know how to find
>> "anonymous-module".
>> I think drracket needs to uniquely name these anonymous-modules and then
>> install a
>> module-name-resolver that can return the correct anonymous module when
>> asked.
>> I assume these anonymous modules exist in the drracket environment, just not
>> on disk.
>> Kevin
>> On 08/30/2011 12:12 PM, Robby Findler wrote:
>>> Kevin: when I follow the steps exactly as written, I get this error
>>> message on stdout (under windows):
>>> standard-module-name-resolver: collection not found: "anonymous-module" in
>>> any o
>>> f: (#<path:C:\Users\robby\AppData\Roaming\Racket\\collects>
>>>   #<path:C:\Use
>>> rs\robby\git\exp\plt\collects>)
>>> I believe this to be a bug in the implementation of 'place' and to
>>> have something to do with the name of the source locations that
>>> DrRacket uses when the file is not saved.
>>> Robby
>>> On Tue, Aug 30, 2011 at 12:14 PM, Kevin Tew<tewk at cs.utah.edu>    wrote:
>>>> When I run the code below in drracket, the code seems to run
>>>> indefinitely.
>>>> When I hit the stop button the (place-channel-get p) sexp is highlighted
>>>> in
>>>> pink.
>>>> Kevin
>>>> On 08/30/2011 08:54 AM, David Mitchell wrote:
>>>> #lang racket
>>>> (define (super-simple)
>>>>    (define p
>>>>      (place ch
>>>>             (place-channel-put ch 5)))
>>>>    (place-channel-get p))
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