Hello,few days ago i opened snap after a long time,and i saw this block i never seen before.

warp {}::grey

What is this block for? Thanks.

It does the same as this:

run script {
} without screen refresh :: control

{} Follow Discussion :: ring sensing

Let's say we have the following script

repeat (100)
move (1) steps
end

You might think it behaves in the same way as this:

move (100) steps

However, it isn't. At the end of each loop iteration, Snap! will update the screen and artificially pause for a bit. This makes the sprite smoothly glide across the screen, rather than jump in one go 100 pixels.

The little pauses can be useful if you're animating, but they can slow down your script when you don't want them. “warp” disables these pauses.

warp {
repeat (100)
move (1) steps
end
} :: grey

Is therefore exactly the same (in terms of behavior) as:

move (100) steps

However, don't put any infinite loops or ‘wait’ blocks inside, as it might hang (it's trying to execute its contents as fast as it can – it'll struggle to do that with an infinite loop).