bharvey wrote:

Now it won't load for me at all – I just see a blank screen. It hates me.

jokebookservice1 wrote:

Is it your white on black browser-injected CSS? Perhaps you have a special case for Snap! that doesn't work here?

bharvey wrote:

jokebookservice1 wrote:

Is it your white on black browser-injected CSS? Perhaps you have a special case for Snap! that doesn't work here?

No, I tried it on Chrome, which I use only for Snap! so it's set up “normally.” I'll try again when I have more time, which probably means next week.

_nix wrote:

ironmannn wrote:

Speaking of which, how come I cant write something like this within the block?

function ExampleFunc ()
{
  this.gotoXY(0,0);
};

ExampleFunc();

it just errors out and returns “this.gotoXY is not a function”

That's because of JavaScript's annoying scoping issues – basically “this” will become undefined in ExampleFunc. (PS, you should probably be starting your function names with lower case letters, likeThis! That's just the global JS convention.)

var myself = this;
function exampleFunc ()
{
  myself.gotoXY(0, 0);
}
exampleFunc();

That should work. In that case, you're storing the this-object (the sprite) in a variable called “myself”, which you can access from exampleFunc.

You can also use “bind” to change the value of “this” within that function:

function exampleFunc() { /* ... */ }
exampleFunc = exampleFunc.bind(this);
exampleFunc();

Or you could use the “new” ES6 arrow functions, which keep the value of the this-object from the this-object that created it:

var exampleFunc = () => {
  this.gotoXY(0, 0);
};
exampleFunc();

_nix wrote:

ironmannn wrote:

Speaking of which, how come I cant write something like this within the block?

function ExampleFunc ()
{
  this.gotoXY(0,0);
};

ExampleFunc();

it just errors out and returns “this.gotoXY is not a function”

That's because of JavaScript's annoying scoping issues – basically “this” will become undefined in ExampleFunc. (PS, you should probably be starting your function names with lower case letters, likeThis! That's just the global JS convention.)

var myself = this;
function exampleFunc ()
{
  myself.gotoXY(0, 0);
}
exampleFunc();

That should work. In that case, you're storing the this-object (the sprite) in a variable called “myself”, which you can access from exampleFunc.

You can also use “bind” to change the value of “this” within that function:

function exampleFunc() { /* ... */ }
exampleFunc = exampleFunc.bind(this);
exampleFunc();

Or you could use the “new” ES6 arrow functions, which keep the value of the this-object from the this-object that created it:

var exampleFunc = () => {
  this.gotoXY(0, 0);
};
exampleFunc();

doloop wrote:

Is there a way to create a named (non-anonymous) function with the javascript block?

Chibi-Matoran wrote:

I made a hash set class: https://snap.berkeley.edu/snapsource/snap.html#present:Username=chibi-matoran&ProjectName=hashset

doloop wrote:

I'm experimenting with the javascript block. I don't know javascript but I want to learn it to expand my options with Snap! As an experiment, I inserted all of the example code above into the second slot (between the braces). Much to my surprise it worked. I was surprised because the block nested the example function inside of an anonymous function. I thought it would do that, but I also thought that would return an error (as I said, I don't know javascript). It is good that this works, but it seems “ugly.” Is there a way to create a named (non-anonymous) function with the javascript block?

// Do step 1, then..
requestAnimationFrame(function() {
  // Do step 2, then..
  requestAnimationFrame(function() {
    // Do step 3, then..
    requestAnimationFrame(function() {
      // Do step 4, then..
    });
  });
});

function step2() {
  // Do step 2, then..
  requestAnimationFrame(step3);
}

function step3() {
  // Do step 3, then..
  requestAnimationFrame(step4);
}

function step4() {
  // Do step 4, then..
  requestAnimationFrame(step5); // And so on.
}

bharvey wrote:

Chibi-Matoran wrote:

I made a hash set class: https://snap.berkeley.edu/snapsource/snap.html#present:Username=chibi-matoran&ProjectName=hashset

Nice. One slight problem I had reading your code is that you have a variable named “method” whose value is not a method (i.e. a procedure) but rather a message.

Oh, not in the code but in your example, maybe you already know this, but generally when you make a hash table you want to pick a prime number of buckets, rather than a power of two, so that regularities in the data (e.g., suppose all your numbers were even) get spread out among the buckets. (Sorry, as I said in another context, I can't help it, I'm a teacher.)

joefarebrother wrote:

This is why I think JS could have CallCC as a primitive. Since “callback hell” is essentially continuation passing style, which CallCC would allow you to avoid and allow you to put a sleep function or a web request in some place without having to completely restructure the program.

Chibi-Matoran wrote:

Where may I find documentation for the JS interface to the Snap! data?

_nix wrote:

joefarebrother wrote:

This is why I think JS could have CallCC as a primitive. Since “callback hell” is essentially continuation passing style, which CallCC would allow you to avoid and allow you to put a sleep function or a web request in some place without having to completely restructure the program.

I'm just curious, then – and excuse me for never properly understanding CallCC – how do I do something like this?



That runs the “play note” block later, but also now. I kind of always thought passing a continuation would delay it until I choose to call it; how would one do that using continuation-passing, and what's the reason for it not being that way?

_nix wrote:

I kind of always thought passing a continuation would delay it until I choose to call it; how would one do that using continuation-passing, and what's the reason for it not being that way?

set [done v] to <(false :: #B80000) :: operators>
launch ({
  wait (2) secs
  set [done v] to <(true :: #00B800) :: operators>
} @addInput :: grey ring) @addInput :: control
wait until (done)

_nix wrote:

Generally my solution for a case like that is this:

set [done v] to <(false :: #B80000) :: operators>
launch ({
  wait (2) secs
  set [done v] to <(true :: #00B800) :: operators>
} @addInput :: grey ring) @addInput :: control
wait until (done)

<(1) is [even v] :: operators>
<(num # = 1) is (a = even) :: operators> :: control hat
if <(a) = [prime]> :: control
report [] :: cap control
end
. . .