[racket] why is the comparimng always false

From: Roelof Wobben (r.wobben at home.nl)
Date: Sat Jun 30 03:03:41 EDT 2012

Op 30-6-2012 1:38, Neil Van Dyke schreef:
> Stephen Bloch wrote at 06/29/2012 06:01 PM:
>> Either you introduce this stuff much better than I do, or your 
>> students are much sharper.
> For the possible benefit of any students reading, I think someone say 
> it, rather than leave it implied: Or the difference could be an 
> isolated effect of, say, some subtle difference in how one concept was 
> first introduced in their respective educations, not a reflection on 
> the instruction or students overall.
> Aside: I think students are much the same everywhere, and most all 
> students have potential to be good at this stuff.  But learning this 
> stuff well requires a lot of work, and I think students generally do 
> need to have sufficient sense that they're ``sharp,'' so that they 
> stick with it and put in the necessary work.  Or, there is another 
> category of person, who sees themself as slow but determined; that 
> will also lead to learning the stuff, if the self image gets them to 
> put in the necessary work.  (However, the ones who are self-assured 
> and yet who don't do the learning work... they are doomed to be dim 
> and to have few job options other than some kind of politician.)
> Neil V.
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>  Racket Users list:
>  http://lists.racket-lang.org/users

Im rereading the chapter and I think I found a piece of the puzzle.

In the chapter there is a mention of this :

;A SIGS(short for "space invader game state") is one of:
;--(make-aimUFO <#%28tech._mix._ufo%29>Tank <#%28tech._mix._tank%29>)
;--(make-firedUFO <#%28tech._mix._ufo%29>Tank 
<#%28tech._mix._tank%29>Missile <#%28tech._mix._missile%29>)

I can do the same for my problem.

; A Vanimal is one of :
; - (make-Vcat ( x happiness)
;   (make-Vcham ( x happiness)

So Vanimal is not a struct but strictly a name.

Am I on the right track.


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