[plt-scheme] Delay/force printing behavior in advanced student language

From: Mark Engelberg (mark.engelberg at gmail.com)
Date: Sun Nov 1 17:10:14 EST 2009

It was pretty obvious how to change it, but now when I run advanced
student language, I get:
require: namespace mismatch; reference (phase 0) to a module
"C:\Program Files\PLT\collects\scheme\private\kw.ss" that is not
available (phase level 0)

When I change the file back to the way it was, I get the same problem.
 So I'm thinking somehow I corrupted the various dependencies or
compilation process.

How do I rebuild everything to incorporate the changed file?



On Sun, Nov 1, 2009 at 1:38 PM, Robby Findler
<robby at eecs.northwestern.edu> wrote:
> I don't think that there is any particular reason. The relevant
> library is pconvert.ss, if you wanted to sort out how to change it.
> Robby
> On Sun, Nov 1, 2009 at 2:58 PM, Mark Engelberg <mark.engelberg at gmail.com> wrote:
>> Compare the printing behavior of delays in student languages versus
>> the module language by executing the following code:
>> (define a (delay 2))
>> (force a)
>> a
>> In the module language:
>> #<promise!2>
>> In the advanced student language:
>> (delay ...)
>> Note that the way it prints in module language gives you information
>> about the contents of the promise once it has been forced.
>> It seems like the advanced student language should give at least as
>> good information as the module language.
>> Therefore, I would like to see it print as:
>> (delay ...) before it is forced and
>> (delay 2) once it has been forced.
>> Any particular reason it doesn't do this?
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