Scratch

bharvey wrote:

Well, the part about project files is more closely tied to the evaluation model.  It would make me very happy if a project were a text file, so I could debug in emacs!

Instead of all this business about running BYOB4 on top of a JS-based Scheme interpreter, why not just compile the blocks to pure JS and execute it? I would love for BYOB to eventually become a way to write vanilla Javascript, which as someone here pointed out, is arguably the most-used programming language in the world. And as browsers get better, BYOB will only become faster, without you guys doing a thing!

xly wrote:

...continue

...and pleasant to use, for all ages from 7 to 77 years. This is the basic project of Scratch , raisen at a much higher level by Brian/Jens without losing the original principles of Scratch. (Consider for example the millions of Scratch projects whereas not a single book has been edited to support this language. Compare with the hundreds of books of many hundred of pages dedicated to JS !!)

To me the applications of BYOB in its 2011 version are more limited by the creativity of Byobers rather than by its lack of technical "bells and whistles" .

OTOH there is no doubt that the team Brian/Jens is perfectly able to invent a new JS-killer "programming language", but this is a totally different story. BYOB should be finalized like it is now, in line with the Scratch spirit...And from then on, up to the 2 genial parents of BYOB 2 to start with a new adventure by inventing (not from scratch !) a new project with a totally different agenda, for example Pad-Web applications.

In the meantime I've improved my initial project at - http://www.xleroy.net/ByobTuto/New/Thumbnails.html - by using most of the new BYOB features.

If you like BYOB as it is now you can always keep the old version handy but what they are talking about is amazing and I would not be one to try and sway them.
BTW- I like your latest project, it makes scrolling a lot more elegant and far less glitchy when you do it that way, Thanks

Last edited by 14God (2011-02-14 18:24:20)

Jens wrote:

But once we're done we'll totally pwn, right?! 

BYOB already makes Scratch look like pretty bad and won't flash make Scratch slower? Yeah it'll pwn!

Last edited by 14God (2011-02-14 18:25:03)

fullmoon wrote:

Instead of all this business about running BYOB4 on top of a JS-based Scheme interpreter, why not just compile the blocks to pure JS and execute it?

Yeah, that's what Jens wants to do.  I don't mind, really, except that JS has syntax to deal with, whereas a Scheme program is already a parse tree with no syntactic nonsense.  A related point is that a Scheme program is already data -- a deep list -- and so it's very easy to have self-reflective programs.  By contrast, neither a BYOB nor a JS program is in a form that can reasonably be manipulated as data.

But Jens might wear me down on this one. 

chalkmarrow wrote:

It's great to see how BYOB is evolving, and I particularly hope that something like CS10 ends up as the basis for future high school AP CS courses. From the Berkeley site, it looks like a great class.

Wow, thanks!  There are pretty good odds that BYOB will end up being at least one of the languages for the new AP.  We're working with high school teachers who are trying to present the material to high school kids, typically not running exactly our course, but borrowing units from us for their own purposes.  And we know several other high school teachers who are writing their own BYOB-based curricula.  It's all very exciting.

(You should see the final projects that last semester's CS10 kids did!  They're all amazing.)

nXIII wrote:

Yep, with a list you don't need any new blocks. However, I find the lists-for-data idea potentially a little confusing. For example, if a user has "first name of," "last name of," and "full name of" blocks which operate on a list with three items as well as a color utility which also operates on a list with three items, they are allowed to use the name-list in the color-util function and, furthermore, the block cannot tell anything is wrong. I prefer being able to call "is (input) a (color)" (a custom block, naturally) and define custom types in order to give informative error messages and validate input rather than having code which runs fine & doesn't give any error messages but doesn't run properly.

Indeed.  I grew up (at the MIT AI Lab) with the slogan "don't protect the user from himself."  That position has definitely influenced the design of Scheme (at MIT) and BYOB.  On the other hand, the next Scheme standard (in the works) will have some form of enforced data abstraction built in.

But it's easy enough to build your own, if you feel the need.  Just use the first element of every list to store its data type.  (At one point I was advocating a feature that if the first element of a list is a command, it's used as the print procedure for this list, so, e.g., you could represent 2/3 as the list whose three elements are

THE SCRIPT [JOIN [ITEM 2 OF < >] [JOIN </> [ITEM 3 OF < >]]]
2
3

and when you SAY it, you see 2/3 instead of a list box.  I still like this idea but we haven't gone anywhere with it.)

Anyway, your procedures can check for a type tag as the first item of the list if you want to protect yourself.

I suppose we could help you out by adding a Predicate slot in the long form input dialog for a type-checking predicate that reports True if the input is the right kind of thing, so we'd be doing the enforcing, but only if you ask for it.

Also, this leads to bad naming conventions such as using arbitrary numerical indices to describe a certain property of an object.

... as I did in the print-rational procedure above.  You're right, I should have defined selectors NUMERATOR and DENOMINATOR but I wanted the example to be readable on its own.  In my own code I generally try to have abstract selectors for the members of a finite non-variadic data type.

One of our goals should be to be able to write, in BYOB, a block that would look like

MAKE-SELECTORS <rational> [LIST <numerator> <denominator>]

and the result would be to define

NUMERATOR-RATIONAL <rational>
  REPORT [ITEM <2> OF <rational>]

DENOMINATOR-RATIONAL <rational>
  REPORT [ITEM <3> OF <rational>]

We can do it if we have first class variables! 

Last edited by bharvey (2011-02-14 19:08:00)

Funny to think we didn't start with a page 113 today.

xly wrote:

(Imagine the potential of Byob + 3D applications !!!)

Provided that it was fast enough BYOB would have kids making some pretty sweet programs.

"I think I talk too much" -me

Last edited by 14God (2011-02-14 19:55:45)

Yet another experimental release:

Jens wrote:

This build once again changes invisible things:

     - the ATTRIBUTE reporter can now be dropped into Boolean slots
     - the functionality of the experimental GET _ OF _ block has been merged into the _ OF _ block

Now there is only one OF block again (the "old" one known from Scratch and previous versions of BYOB), and it is supposed to support all existing Scratch and BYOB projects as well as the new crazy attribute stuff without ever evaluating its object slot "accidentally" (in case there's a CLONE reporter in there).

There are some hairy details to this, so please let me know if you come upon any major glitches (aside from the fact, that recent projects that use the interim OF block will no longer be able to use it).

Enjoy!
--Jens

bharvey wrote:

chalkmarrow wrote:

It's great to see how BYOB is evolving, and I particularly hope that something like CS10 ends up as the basis for future high school AP CS courses. From the Berkeley site, it looks like a great class.

Wow, thanks!  There are pretty good odds that BYOB will end up being at least one of the languages for the new AP.  We're working with high school teachers who are trying to present the material to high school kids, typically not running exactly our course, but borrowing units from us for their own purposes.  And we know several other high school teachers who are writing their own BYOB-based curricula.  It's all very exciting.

(You should see the final projects that last semester's CS10 kids did!  They're all amazing.)

Great to hear. As I may have mentioned ('complained') to Jens , there's a real void in public high school CS programs these days, I think, even compared to the early 80's.  In the old days, we all got excited and stayed after school to type Basic programs from Byte into the TRS-80s or Apple IIs that were stored in the corner of the math classroom. Now, 11th graders are told, on the first day of AP CS, "start your programs with 'public static void main(String [ ] args)', and we'll tell you why later."  I think something like CS10 is exactly what we need. The fact that "Kinect," "Recursion," and "Game Theory" all appear on your CS10 web page is all I need to know 

chalkmarrow wrote:

The fact that "Kinect," "Recursion," and "Game Theory" all appear on your CS10 web page is all I need to know 

Don't forget my favorite, higher order functions! 

fullmoon wrote:

I don't know if I'm going to take AP CS, but I'd sign up today if it was in BYOB!

This course isn't meant to replace the Java-based AP CS A.  This one is the "CS 0" course for humanities types with no programming experience.  Anyway, you'll be in college before the AP people get around to writing a CS Principles (which is what they call it) exam.

bharvey wrote:

Doesn't tempt me at all -- I'm not a graphics person!

The Scratch Team made a deliberate decision to go with 2-D graphics and I think they were right about that.  People who program in Alice (3-D) put a ton of effort into getting the camera position and angles right, none of which has any intellectual interest.

/My/ idea of what we should add to get sweet kid programs is text boxes! 

What about 3d math? I had to learn a lot to use 3d environments as apposed to 2d ones. But If Jens wants to make it so BYOB is backwards compatible with JS so you can edit any JS program with it, then I could use my uncles game engine(3d) and script my program with BYOB.

14God wrote:

What about 3d math? I had to learn a lot to use 3d environments as opposed to 2d ones.

If you wanted to write your own 3D library in BYOB, then you'd learn some trigonometry.  But if we do that work for you, I don't see where the math comes in.

P.S. You and fullmoon should just learn Scheme.