On Jul 16, 2011, at 1:58 PM, Shriram Krishnamurthi wrote:
> On Sat, Jul 16, 2011 at 11:16 AM, Stephen Bloch wrote:
>>
>> Here's another idea: provide a "sprite+picture" structure, and have all the
>> operations take in and return it.
>
> This is unwieldy beyond measure in our syntax.
Yes, th
On Sat, Jul 16, 2011 at 7:33 AM, Stephen Bloch wrote:
> These functions would presumably maintain the invariant that each name
> corresponds to at most one sprite in a world. Letting the kids manipulate
> the list of sprites directly does NOT maintain that invariant, so I think I
> have to do
On Sat, Jul 16, 2011 at 11:16 AM, Stephen Bloch wrote:
>
> Here's another idea: provide a "sprite+picture" structure, and have all the
> operations take in and return it.
This is unwieldy beyond measure in our syntax.
Shriram
_
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Matthias Felleisen írta:
>
> And that leaves only one option: start with mathematical-style programming
> because we know that this is mathematics and there is no transfer needed. It
> is the *same* skill.
Just my 2 cents. :-)) I fully agree with this.
We teach "web programmers". They learn
On Jul 16, 2011, at 10:33 AM, I wrote:
> some version of [each sprite having a name] may be the least-bad idea so far,
> including mine :-)
Here's another idea: provide a "sprite+picture" structure, and have all the
operations take in and return it. One could use it directly as a world in
bi
On Jul 16, 2011, at 10:55 AM, Stephen Bloch wrote:
> I have a hard time believing that EVERY CS educator who evangelizes for
> something other than PBD "has no scruples".
I made a typically Matthias-strong statement and I need to explain what I mean.
1. We want to teach every child how to
On Jul 16, 2011, at 10:34 AM, Matthias Felleisen wrote:
> Since these people have no scruples -- don't even understand that they dont
> have any -- go for the imperative version.
I have a hard time believing that EVERY CS educator who evangelizes for
something other than PBD "has no scruples".
On Jul 16, 2011, at 10:16 AM, Stephen Bloch wrote:
> I'm looking at our competition in the marketplace of ideas, and I want to
> beat (or at least match) them at their own game.
>
> Who's with me?
Since these people have no scruples -- don't even understand that they dont
have any -- go for t
Mark Engelberg wrote:
> I see you're already representing the World as a picture and a list of
> sprites, so just let the kids manipulate that directly.
>
> Since you want to support multiple sprites, what if each sprite in the
> sprite list had a name, so the contract is:
> move: String (sprite-
On Jul 16, 2011, at 12:46 AM, Nadeem Abdul Hamid wrote:
> Ah, right. How about you keep the picture separate, and functions like
> 'move', 'rotate', etc. add to a list in the sprite structure; when the sprite
> structure is passed to the draw handler, the draw handler updates the picture
> bas
Carl Eastlund wrote:
> Why is affecting the sprite "functional" and affecting the picture
> "imperative"? Any part of a program can be mutated imperatively, and
> likewise any part of a program can be passed around functionally. If
> you need to modify the picture, why not pass around the pictur
On Jul 15, 2011, at 3:12 PM, Matthias Felleisen wrote:
> I don't understand your solution. But if students cannot test their event
> handling functions in a functional style, then the answer to the last
> question is YES, you're pregnant.
Based on my toy examples so far, they can test their e
On Sat, Jul 16, 2011 at 12:34 AM, Mark Engelberg
wrote:
>
> Because the image is not only dependent upon the current location of
> the sprite, but also the entire history of the sprite's movements when
> its pen was down. So you either have to store a very long list of
> line segments in the worl
On Fri, Jul 15, 2011 at 11:56 AM, Stephen Bloch wrote:
> Last Monday I attended Dan Garcia's workshop on BYOB. He kept pointing out
> (presumably for the benefit of Emmanuel and me) that it really is a
> functional language. And yes, it has "map", "filter", "foldl", and
> "lambda"... but most
On Fri, Jul 15, 2011 at 12:24 PM, Nadeem Abdul Hamid wrote:
> Why don't you just have the picture generated based on the state of the
> sprite each tick of the animation, just as in HtDP "world"? Functions like
> move, rotate, etc. produce a modified sprite, and when that sprite gets
> passed to
On Fri, Jul 15, 2011 at 2:56 PM, Stephen Bloch wrote:
> The problem is that some sprite actions (most obviously, "move" when you're
> in pen-down mode) affect not only the sprite itself but the world's picture.
> So far the least-bad solution I've come up with is to hide a mutation of
> that pic
On Fri, Jul 15, 2011 at 2:56 PM, Stephen Bloch wrote:
> Last Monday I attended Dan Garcia's workshop on BYOB. He kept pointing out
> (presumably for the benefit of Emmanuel
> and me) that it really is a functional language. And yes, it has "map",
> "filter", "foldl", and "lambda"... but most o
On Jul 15, 2011, at 2:56 PM, Stephen Bloch wrote:
> I've experimented with a couple of ways to do that. One way is to define (in
> my code, not visible to student code) a box named "world-pic", which is
> set-box!ed in "move" and "run-byob-world". Another is to use just a plain
> variable an
Last Monday I attended Dan Garcia's workshop on BYOB. He kept pointing out
(presumably for the benefit of Emmanuel and me) that it really is a functional
language. And yes, it has "map", "filter", "foldl", and "lambda"... but most
of the examples and assignments one normally does in BYOB use v
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