Discuss Scratch

bharvey
Scratcher
1000+ posts

Snap! user discussion

edward789121 wrote:

nope, it does something once (function λ), and then returns the reporter (var λ).
Yes, I understand what your block does. I was using a loop as an example to explain why the language lets you control explicitly when the script is run – you might want to do it more than once. Your own use case is simpler.

Do you still need help, after jfb's posted script using the RUN block? Are we both misunderstanding what's standing in your way?

f1lip
Scratcher
1000+ posts

Snap! user discussion

The for () = () to () block isn't there. Is this a glitch or was it removed or something?
joefarebrother
Scratcher
500+ posts

Snap! user discussion

I just encountered a weird bug - The JavaScript block seemed to be running more than once sometimes, and I couldn't figure out any pattern to how many times it ran. But when I opened another project to test it, I couldn't reproduce it, and when I opened back up the original project it was affecting, it stopped happening.

It's a Heisenbug


And it was delicious! Play TBGs! Check out my Scheme Interpreter!
;
joefarebrother
Scratcher
500+ posts

Snap! user discussion

f1lip wrote:

The for () = () to () block isn't there. Is this a glitch or was it removed or something?
Click the file menu, then click “import tools”


And it was delicious! Play TBGs! Check out my Scheme Interpreter!
;
edward789121
Scratcher
500+ posts

Snap! user discussion

bharvey wrote:

edward789121 wrote:

nope, it does something once (function λ), and then returns the reporter (var λ).
Yes, I understand what your block does. I was using a loop as an example to explain why the language lets you control explicitly when the script is run – you might want to do it more than once. Your own use case is simpler.

Do you still need help, after jfb's posted script using the RUN block? Are we both misunderstanding what's standing in your way?
the run block just spawns what i put in.

my website go there if you want information about me.
edward789121
Scratcher
500+ posts

Snap! user discussion

joefarebrother wrote:

You need to use the run block for the c section, and the call block for the unevaluated variable. So your code will be

(do (function λ) for (var λ)::operators) :: control hat   
run (function) :: control
report (call (var) :: control) :: control cap

Someone else will be able to explain this better than I can.
Inside: error
expecting a ring but getting (getting whatever var is)

my website go there if you want information about me.
joefarebrother
Scratcher
500+ posts

Snap! user discussion

Oh, you need to make the type of var “Any (Unevaluated)”, that way it's automatically wrapped in a ring for RUN to handle.


And it was delicious! Play TBGs! Check out my Scheme Interpreter!
;
f1lip
Scratcher
1000+ posts

Snap! user discussion

joefarebrother wrote:

f1lip wrote:

The for () = () to () block isn't there. Is this a glitch or was it removed or something?
Click the file menu, then click “import tools”
Thanks!
joefarebrother
Scratcher
500+ posts

Snap! user discussion

Jens, can you explain how WARP works and why sometimes it makes things faster, and sometimes slower?


And it was delicious! Play TBGs! Check out my Scheme Interpreter!
;
bharvey
Scratcher
1000+ posts

Snap! user discussion

IANJ, but let me give this a try.

So, you understand that your computer is only as fast as it is, and all WARP can do is speed up one piece of computation at the expense of other pieces.

In particular, nothing changes on the display during a WARP. This can result in a subjective speedup because some intermediate displays may be skipped altogether, as for example when you're drawing a fractal tree and it all appears at once, instead of displaying each MOVE. On the other hand, if you're using a change in the display to measure the progress of a computation, it'll subjectively slow down because nothing changes for a long time.

I think the interaction between WARP and display uodating explains most cases of speedup or slowdown. But of course WARP also prevents other scripts from running, so if other scripts (same sprite or other sprites) contribute to “things,” that may result in a subjective slowdown.

And of course if the warped computation runs long enough for the browser to decide Snap! is being unresponsive, that can lead to a big increase in actual elapsed time. (This shouldn't happen, though, because Snap! interrupts even warped threads if they run for a long time.)

joefarebrother
Scratcher
500+ posts

Snap! user discussion

Well, I was warping a block that just did calculations, no display work, and was comparing it with RESET TIMER and TIMER, and when unwarped it had a time of 0, but when warped it was 0.1.

This function is called in a loop, so I thought it was important to optimise


And it was delicious! Play TBGs! Check out my Scheme Interpreter!
;
bharvey
Scratcher
1000+ posts

Snap! user discussion

Okay, you've gone beyond my expertise. My guess is that it has to do with when the timer gets updated, but I'm not sure. What happens when you time the entire loop? Is the time difference significant?

NoMod-Programming
Scratcher
1000+ posts

Snap! user discussion

bharvey wrote:

Okay, you've gone beyond my expertise. My guess is that it has to do with when the timer gets updated, but I'm not sure. What happens when you time the entire loop? Is the time difference significant?
Probably because the warp block doesn't actually warp the blocks; it only stops the display from updating while it is run. Therefore, it has to make sure the display doesn't update and has to affect every yield that will be called, which could be time consuming.

NOTE: I don't know much about snap!'s code, so I may be (and probably am) wrong

Last edited by NoMod-Programming (June 12, 2016 20:45:55)


Long-since moved on from Scratch, if you need to find all my posts, search this in google: 3499447a51c01fc4dc1e8c3b8182b41cb0e88c67
Jonathan50
Scratcher
1000+ posts

Snap! user discussion

I made a Snap! “wrapper” around JavaScript's websocket client. The project is here.

Last edited by Jonathan50 (June 13, 2016 07:40:27)

joefarebrother
Scratcher
500+ posts

Snap! user discussion

Jonathan50 wrote:

I made a Snap! “wrapper” around JavaScript's websocket client. The project is here.
Interesting!


And it was delicious! Play TBGs! Check out my Scheme Interpreter!
;
bharvey
Scratcher
1000+ posts

Snap! user discussion

Now all we need is a way for a Snap! project to make itself a server. We could do that in a standalone node.js implementation, right?

liam48D
Scratcher
1000+ posts

Snap! user discussion

bharvey wrote:

Now all we need is a way for a Snap! project to make itself a server. We could do that in a standalone node.js implementation, right?
That's actually what I was going for back a couple of months ago with the invoking-snap-blocks-in-JS thing

202e-202e-202e-202e-202e UNI-CODE~~~~~
klortho
Scratcher
29 posts

Snap! user discussion

Jonathan50 wrote:

I made a Snap! “wrapper” around JavaScript's websocket client. The project is here.
Did you take it down, or am I missing something? I just tried to check it out, and it looks like an empty project to me.
klortho
Scratcher
29 posts

Snap! user discussion

I have a very general question about the higher-order function features of Snap!. Is there any sort of tutorial material for learning about these, other than the reference manual? I've been trying to go through the ref. man., but is seems like it goes from very basic, to extremely difficult, in a giant quantum leap.
Jonathan50
Scratcher
1000+ posts

Snap! user discussion

klortho wrote:

Jonathan50 wrote:

I made a Snap! “wrapper” around JavaScript's websocket client. The project is here.
Did you take it down, or am I missing something? I just tried to check it out, and it looks like an empty project to me.
I added custom blocks to the sensing palette.

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