[racket] Suggestion: Allow above, beside etc. to accept a single image.

Good to understand the trade-off.  In a  similar vein I see that in BSL (+
...), for example, requires at least two arguments vs zero or more in
racket.

I did find it a little odd that I had recourse to use a "teachpack" to gain
access to this nice set of general-purpose drawing abstractions. Are the
facilities provided in 2htdp/image used a fair bit in non-teaching
contexts? If so,
would it make sense to factor out a racket-oriented library at some stage?

Dan


On Tue, Oct 22, 2013 at 5:33 AM, Matthias Felleisen <matthias at ccs.neu.edu>wrote:

>
> This is of course a symptom of the more general problem that we fail to
> have a mechanism that specializes a module to a particular language
> context. In *SL, the restriction is absolutely great; in Racket, the
> restriction is a pain. Note that units wouldn't solve the problem cleanly
> either -- Matthias
>
>
>
>
>
>
>
> On Oct 22, 2013, at 8:14 AM, Robby Findler <robby at eecs.northwestern.edu>
> wrote:
>
> > I did this explicitly because (I believe) it helps with parenthesis
> errors when beginning students make simple mistakes using the library. For
> more advanced programmers, it seems straightforward to define things like:
> >
> > (define (above* . is) (cond [(null? is) (blank)][(null? (cdr is)) (car
> is)][else (apply above is)])
> >
> > and you can even abstract that as a function that takes something like
> above and builds an above* from it.
> >
> > Robby
> >
> >
> > On Mon, Oct 21, 2013 at 10:58 PM, Daniel Prager <
> daniel.a.prager at gmail.com> wrote:
> > Currently above from 2htdp/image requires at least two arguments. I.e.
> >
> > procedure
> > (above i1 i2 is ...) → image?
> >
> > Recently I have been using an idiom where I stack a list of one or more
> images.
> > I.e.
> >
> > (apply above list-of-images)
> >
> > I have a workaround, but it seems to me that a more tolerant "above" --
> which acts as an identity when passed a single image -- would be an
> improvement to the
> > library.
> >
> > Similarly for beside, etc.
> >
> >
> > Dan
> >
> > ____________________
> >   Racket Users list:
> >   http://lists.racket-lang.org/users
> >
> >
> > ____________________
> >  Racket Users list:
> >  http://lists.racket-lang.org/users
>
>


-- 
*Daniel Prager*
Agile/Lean Coaching, Software Development and Leadership
Twitter: @agilejitsu <https://twitter.com/agilejitsu>
Blog: agile-jitsu.blogspot.com
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