[racket] Typo in signatures

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Tue Oct 4 17:21:06 EDT 2011

Did you see Danny's reply pointing you at


? There's also equal~? in the teaching languages.


On Tue, Oct 4, 2011 at 4:15 PM, John Riedl <riedl at umn.edu> wrote:
> Of course something like check-within is what is needed.  The point
> is: there ought to be something like check-within that can be used in
> a function to test "equality within a delta".
> I suppose it's fine for each student to define one herself; I'm just
> saying I think it's so important it ought to be built-in.
> Best,
> John
> On Tue, Oct 04, 2011 at 02:23:16PM -0400, Shriram Krishnamurthi wrote:
>> check-within
>> http://docs.racket-lang.org/test-engine/index.html#(def._((lib._test-engine/racket-tests..rkt)._check-within))
> Yes.  That's exactly what students should be using ubstead of anything
> that even looks like an equality-test.  The only time you'd want an
> actual equality test on inexact numbers is whan you're using it
> algorithmically instead of numerically, such as attaching a memo-pad to
> a function on inexactt numbers.
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