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

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Sun Nov 1 16:38:34 EST 2009

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.


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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