Scratch

06dknibbs wrote:

There may be a problem with this, if the block is removed now that so many projects use it, some of the older projects may become unplayable as Scratch won't support that block.

Actually, if you see there's some projects of Scratch like http://scratch.mit.edu/projects/RHY3756547/1059859 in which it includes an old block (Stretch), and works online. And this would be for Scratch 2.0-All Scratch 1.4 block games would be playable, as we can play older Scratch games. The player supports all of the blocks of new and old versions-Scratch, on the other hand, doesn't. So the project would work online yet not offline. 

Delete "forever if" ?

Not going to happen.

jslomba wrote:

EdnaC wrote:

Delete "forever if" ?

Not going to happen.

Why?

The ForeverIf block is Scratch's "while loop", common in most computer languages.

From Wikipedia:

"In most computer programming languages, a while loop is a control flow statement that allows code to be executed repeatedly based on a given boolean condition."

*This block is used by Scratchers more than the (very common) "If-Else" block. 

*It replicates a syntax that is common in other languages.  (Part of the idea of Scratch is to let people learn programming.)

*It's more sensible than using a "Forever" loop, because it can be used to turn off a loop that isn't needed - speeding up the project.

Yes, you could do the same thing with an "If" inside of a "Forever" loop, but there are lots of blocks you could do without by combining other blocks. 

ForeverIf is here to stay (IMHO).

JTxt wrote:

Yes, if it behaved like "while loop", it would make sense and be more useful, but it does not.
Instead it is a "if, loop forever" and causes confusion.

You are incorrect.  It is a "pre-test" while loop.  If the boolean is true the loop runs, if the boolean is false, looping stops.  The loop will restart if the boolean becomes true again.  According to the Scratch Wiki, this block is also somewhat faster than the "workaround".

JTxt wrote:

it is a "if, loop forever" and causes confusion.

JTxt is an experienced scratcher and even he doesn't know how the block works.

This is exactly what I'm talking about.  The block is not clear on what it does.

06dknibbs wrote:

There may be a problem with this, if the block is removed now that so many projects use it, some of the older projects may become unplayable as Scratch won't support that block.

Not at all!

I propose that whenever a project is opened, if it contains a

<forever if>
<end>

it would be silently replaced with

<forever>
<if>
<end>
<end>

BoltBait wrote:

Not at all!

I propose that whenever a project is opened, if it contains a

<forever if>
<end>

it would be silently replaced with

<forever>
<if>
<end>
<end>

I'd propose to quietly replace

<forever> with <forever if> (1 = 1)

As I haven't bothered to read the entirety of this thread, I'm just going to state that the block should not be removed but hidden, like motor blocks.

oh man. i rembered it backwards.  sorry.

i see uses for it now but i also think it's confusing and not needed.
But i tend to put multiple ifs and other blocks nested in a loop... 

(i havn't tested forever if yet for speed, but i think doing confusing tricks to apease the interpreter is backwards. including all the 1 sprite 1 script scripting which i do for speed.. but one frame per loop is how they designed this learning language. go byob and atomic blocks!)

TimeFreeze wrote:

It seems to reduce lag, because rather than running a forever, it just runs an if. Right?

With an if inside a forever, the program has to keep running a forever, but this way it is only checking to see if the boolean is true before making any actions.

Am I right, or am I missing something?

IMO I think it should be kept. (If what I've stated above is true)

*According to the Scratch Wiki, Forever If is faster than an If inside a Forever.
*Forever If replicates the "While (boolean is true) Do" loop of other computer languages.
*It is used more by Scratchers than the "If Else" block (according to the Stats).
*It reduces the width of scripts (which can become a problem on small screens).
*It won't be deleted from Scratch.

If the ST deleted stuff that is confusing to people, Broadcasts would be on the chopping block - Look at all of the suggestions to put 'receive' blocks inside scripts, if you understand that a broadcast is an event, this obviously doesn't make sense, ergo, many users don't understand broadcasts.

I put multiple "Ifs" and "If Else" statements inside a "Forever If".  The first condition makes it easy to turn off the script (useful if you wanted to pause, or if the sprite isn't active).

The idea of an unconditional "Forever" statement is pretty odd; In some environments, this would be like stating "lockup my computer, until I use CTRL-ALT-DEL to kill this game".  Scratch protects users from the lockup - but if you are looking at a program in another language, you'd likely see "while (1=1) do".  (Somewhere inside the loop, there would have to be a way to break or exit the loop.)

Early in my projects, I'll use "Forever If (1=1)" for something (like keyboard input) that I always want running.  If I later decide that loop can (or needs to) stop under certain conditions, the change is as easy as putting a "real" condition into the Forever If, otherwise, I just leave the (1=1). 

Think about how easy it is to really screw up a script by tearing it out to make a change and accidentally dropping it where another script sucks it in...

In any case, this block isn't going away - You could work around not having it (but suffer a small performance hit), but this is true of a lot of blocks.  I'd say this entire thread just points out a need to clarify the function of Forever If in the getting started guide and perhaps to use it in some of the sample projects.

Take it off! It's such a waste.

[blocks]It isn't like a while loop. A while loop ends once the condition becomes false, basically like

<repeat until><<  <not>  >> [/blocks]
It should be renamed to something like
|From now on, whenever <> do|
    {a script}

Last edited by joefarebrother (2011-08-08 01:54:34)