Re: [racket] Exercise 5.1.3 HTDP

On Jan 30, 2011, at 1:05 PM, Jeremy Duenas wrote: > Exercise 5.1.3. Develop the function check-guess3. It implements a larger > portion of the number guessing game of exercise 5.1.2 than the function > check-guess. Now the teachpack hands over the digits that the user guesses, > not the numb

Re: [racket] overlay and overlay/xy

I taught from HtDP/2e last semester, using 2htdp/image, and had similar experiences with my students playing with overlay/xy. I must admit it wasn't what I expected after using overlay, and I agree with Don. With the caveat that I'm not concerned about backward compatibility, I would prefer to see

Re: [racket] overlay and overlay/xy

On Sun, Jan 30, 2011 at 10:04 PM, Robby Findler wrote: > Do others that may depend on 2htdp/image have an opinion? Looking at both the code that we've developed for my current course, and the code that students have written (~55k lines), the only uses of `overlay/xy' are as a replacement for `pla

[racket] Exercise 5.1.3 HTDP

*Exercise 5.1.3.* Develop the function check-guess3. It implements a larger portion of the number guessing game of exercise 5.1.2 than the function check-guess. Now the teachpack hands over the digits that the user guesses, not

Re: [racket] overlay and overlay/xy

I find this to be a compelling argument but I am worried about backwards compatibilty for others. The least I can do is a better job documenting this (and thanks to your message I think I'll be able to do that) but I'm not sure about changing the semantics. Do others that may depend on 2htdp/imag

[racket] overlay and overlay/xy

I shifted entirely to using 2htdp/image this semester; now all the pinhole stuff is gone and we can do "image arithmetic" with various combinations of overlay, underlay, above, and beside, which is great. The problem is, overlay/xy now sticks out like a weird wart on the system, and it's profoundl

Re: [racket] HTDP Chapter 4

We are talking to MIT Press about the problem. Please refrain from the hyperbole while we work on this. It's not easy to check a several 100 page book. We also don't know whether the problem is for everyone or just for Duenas (possible, no?). If anyone else has the Kindle edition and can confirm o

Re: [racket] HTDP Chapter 4

On Sun, Jan 30, 2011 at 12:37:40PM -0500, Matthias Felleisen wrote: > > Jeremy, try the on-line version instead of kindle. We are not responsible for > their bugs Sorry -- Matthias But if the Kindle version is tha bad, demand your money back. They shouldn't get away with this kind of crap. --

Re: [racket] Lazy take is the identity?

I'm completely agreeing you on this. In some special cases you might consider applying it in your own code (and not tell anybody :), but definitely not in the source functions to be distibuted and documented. It could get wild after a while. I was experimenting with it to understand how it works,

Re: [racket] Lazy take is the identity?

About a minute ago, Jukka Tuominen wrote: > > Hi, > > a funny coincidence. I was just experimenting with ". args" a few > days ago - the number and order of arguments, that is. I tried it on > "filter" since I always seem to forget the order of arguments. > > (define (my-filter . args);; ignores

Re: [racket] Lazy take is the identity?

Hi, a funny coincidence. I was just experimenting with ". args" a few days ago - the number and order of arguments, that is. I tried it on "filter" since I always seem to forget the order of arguments. (define (my-filter . args);; ignores the order of arguments (filter (car (filter procedure? a

Re: [racket] Lazy take is the identity?

On Wednesday, Mark Engelberg wrote: > P.S. I was surprised to see that list-ref in #lang lazy takes the args in > opposite order than in #lang racket (which takes the list first). You were probably referring to `take' here -- that's a known issue. The lazy version follows Haskell, and was there be

Re: [racket] moby/wescheme & TCO

>> I am wondering if there are documentations on how moby/wescheme solve the >> tail call optimization issue to compile down to javascript.  My google'fu is >> failing me. Hi YC, The current runtime has an interpreter that's explicitly managing the control stack, so it can do the tail-call opti

Re: [racket] HTDP Chapter 4

This is no longer an issue. After checking the website, the problem was that in the Kindle edition of HTDP they leave out the ( < ) symbol. so when trying to compile ( < 4 5) I was getting an error because the book was telling me the syntax was ( 4 5). After realizing that I am actually getting it

Re: [racket] HTDP Chapter 4

Jeremy, try the on-line version instead of kindle. We are not responsible for their bugs Sorry -- Matthias On Jan 28, 2011, at 2:12 AM, Jeremy Duenas wrote: > I am trying to work on the examples in Chapter 4 of HTDP where they are > talking about Boolean expressions, and every time I try to

Re: [racket] moby/wescheme & TCO

I don't have your answer, but an interesting anecdote: I learned recently why the setTimeout(k, 0) trick is so slow. Apparently too many web sites (including nytimes.com, I believe) rely on a minimum delay of somewhere between 4 and 10ms to do animations, so browsers have to throttle the events.