[Newbies] RE: KeyPress On World of Squeak Wonderland (was:Disappointed)

Ron Teitelbaum Ron at USMedRec.com
Wed Nov 8 21:09:20 UTC 2006

Hi Jeff,


This is actually one of the things that I found interesting about
wonderland.  It's a bit too cleaver.  In my block I would have expected to


[:event | self move: #left] since the code is being stored on a helicopter
but instead I needed to put in [:event | helicopter move: #left].  Now it
seems that Wonderland is doing what it is you want but at the expense of
making you believe this is some sort of magic.  


The answer to your question is rather simple, but it will be confusing with
what you have already seen.  


The answer is: Object message.  Every message is sent to an object, and
objects can be either Classes or instances.  But even this is a bit
confusing since Classes are instances of a Class, but forget I mentioned


Now a Class can have instances.  Like this:    aGlass := Glass new.


This sets the temp variable aGlass to an instance of the Class Glass.  It's
relatively easy to find a class in Smalltalk since it does it for you
automatically.  If you had created the class Glass then select Glass and
inspect_it will bring up the class definition.  This is not true for
instances.  You are required to manage your own instances of a class.
Normally we do this by storing instances in instance variables.  This helps
to form a relationship between objects.


So if I did this 


            Object subclass: Glass

                        instanceVariables: 'content'


                        "initialize the instance of Glass"

                        content := OrderedCollection new.


                        "return a collection of matter that represents
contents of a glass"



            Object subclass: Matter


Matter subclass: Liquid


            Liquid subclass: Water


            Matter subclass: Solid


            Solid subclass: Ice


Then I could make an Instance of Ice and put it in the Glass.


            aGlass := Glass new.

            aGlass content add: Ice new.



If I do this then I get back an instance of Glass with some ice in it.  Now
I could set some properties so that ice over time turns into water.


Notice something about this.  If I go to another workspace and do


            aGlass := Glass new.  


I get a new glass, not the same one as before.  Is it possible for me to go
to another workspace and get the same glass back?  Yes but this is not the
way that we normally do things.  If I add an id to glass this will make more


            aGlass := Glass new;

                        id: 'Glass 1';



Now in another workspace I can do: 


            myGlass1 := Glass allInstnaces detect: [:a | a id = 'Glass 1']
ifNone: [Transcript show: 'you need glasses'].


So if this is not how we would normally do things what is?  Well remember
ice?  We made an instance of Ice and it's still in the glass.


            aGlass := Glass new.

            aGlass content add: Ice new.


            If we wanted to get this back in the same code we could use the
aGlass temporary variable to retrieve it.


            myContent := aGlass content at: 1 ifAbsent: [Transcript show:
'you still need glasses'. nil].


            Now myContent has Ice in it.


            (we would actually do something like this instead.  But instead
of talking about methods and browsers since we are still in a workspace, I'm
trying to give you an example that will make sense: 


            aGlass := Glass new.

            myIce := Ice new.

            aGlass content add: myIce.


            See now we don't have to retrieve it back since we already have
a temp variable)


What is wonderland doing?

            Well something very interesting, it is holding onto instances of
Actor and naming them and replacing those names for you.  So while it looks
like you are just using the name, you are really using temporary variables.
Cool huh?


How does all this help you?  Well if you start wonderland in a workspace:


            Wonderland new.


You can inspect this.  (not do_it but inspect_it instead).  You will get
back an inspector which IS the wonderland instance you are looking for.  You
can now write any code you want to try out on the instance.  w or your
instance of Wonderland is now: self, so on your inspector you can do: self
addActor: . or whatever.  You can find your actors, browse code, do all
kinds of cool stuff.  You can not save this code.  This is a way for you to
get used to what's going on.  It's a try it area.  Look around, inspect more
things, browse code that makes up these instances.  


The key take away here is that instances are like children.  They are not
interchangeable.  It's like children.  You don't get the same one each time
you make a new one.  And you don't ask a question of just any child.  You
need to ask your daughter to clean up the backyard, and your son to do the
dishes, or whatever.  


Happy coding,


Ron Teitelbaum

President / Principal Software Engineer

US Medical Record Specialists

Ron at USMedRec.com 





From: beginners-bounces at lists.squeakfoundation.org
[mailto:beginners-bounces at lists.squeakfoundation.org] On Behalf Of Jeff
Sent: Wednesday, November 08, 2006 1:44 PM
To: Ron at USMedRec.com; hombreviii at myway.com;
beginners at lists.squeakfoundation.org
Subject: [Newbies] RE: KeyPress On World of Squeak Wonderland


Thanks Ron,
There's some good info. in there. Unfortunately, scene doesn't have
respondWith: to: method, but I might be able to find a workaround. 

One method I was trying to use in the past was to create a script from
tiles, and have that script always ticking and just send the helicopter the
command to move in response to the world's last keystroke. I couldn't get
the script to find the helicopter at all, and have been having trouble with
going from one workspace to another attempting to refer to the same thing,
and also with the differences between tile scripts and workspace scripts,
for some reason they don't act the same and I'm not sure why. Even when I
tried creating a class MyWonderland with instance variables | wonder copter
|, I couldn't figure out how to get a method to understand what 'copter' was
and pass messages to it other than the one that created it. Also related,
when I define jump as 
jumpup := wonder helicopter move:#up.

I still don't know exactly how to make this method do this again. I've tried
World jumpup. jumpup. wonder helicopter jumpup. but only jumpup loop. seems
to work, and again only from the particular workspace I defined it in. I
know all of this is related somehow. Anyone got a hint?

--- On Wed 11/08, Ron Teitelbaum < Ron at USMedRec.com > wrote:

From: Ron Teitelbaum [mailto: Ron at USMedRec.com]
To: hombreviii at myway.com, beginners at lists.squeakfoundation.org
Date: Wed, 8 Nov 2006 11:07:48 -0500
Subject: KeyPress On World of Squeak Wonderland (was: Disappointed)


Hi Jeff,



Welcome to the beginners list!



I appreciate the fact that you are
sticking with the problem. That in my opinion is the best way to learn. I
didnt answer your question because I do not feel that I am an expert in
Wonderland. If the question was something like how can I map a key to so
some action that is pretty easy, IF that action is an isolated easily called
method. Something like: Utilities garbageCollectAndReport. This is
a class method and there is no instance that needs to be sent to. 



If a key stroke needs to be captured and affect
a running instance it is a bit more difficult to do but still very possible.
issue here is that there is a complicated event loop that needs to be tapped
into but this would be very difficult to explain to someone with limited
The fact that you are using wonderland means that there is probably already
hook to do what you want so a complicated explanation of what I know will
probably only confuse the matter and make things more difficult for you. 



There are people on this list that have
much more experience with Wonderland, but nobody that will answer your
within hours.



I would love to have Squeak be much more a
pleasant experience for you. My suggestion is that you start slower and
work on understanding basic concepts of Squeak. Do more tutorials; look
into how some things work before trying to extend them. 



Also a comment, starting with the
assumption that people are not going to help you is discouraging to people
might. People are more likely to help people that work hard themselves
and will benefit from the help and will appreciate that help. I think you
have the work hard part down. You need to be a bit more appreciative of
the effort and time that goes into helping you.



Now to your question: Matthias was right
and he sent you to exactly the place you needed to go. I just
loaded a 3.8 image and did the helicopter tutorial. I have to say it was
great fun! Wonderland is a very nice piece of code and I can see that it
would be fun to play with. The tutorial is fun but the concepts are not
easy and how the authors did what they did is very clever but also difficult
when you venture off the beaten path. You picked a hard place to
start! That by itself can be very frustrating. 



Here is your answer but the answer is not
perfect. What I noticed is that the keys only have focus when the actor
is under the mouse. There may be a way to make this work in the context
of a world but I couldnt get it to work that way. The world does
not appear to have a reactions collection, but there does seem to be a
little hook
in Scene that might have been intended to work that way. Again this is an
advanced concept. I also tried adding a reaction to the ground to make it
easier for this to work. The ground accepted the reaction but did not act
on it. I added a reaction of [:event | self halt] but that did nothing so
maybe background items like ground and sky dont quite work or dont
respond to certain reactions the way other actors do. It makes sense that
Wonderland might be written this way. If you added a right key press to
multiple objects how is it supposed to know which item the key press should
control. There could be a number of ways to fix this like adding an actor
that is a control stick or something, then placing the mouse over the
stick would work the helicopter. (just a suggestion of where you might go
from here)



Ok so here is the code: 



helicopter addResponse: [:event | 


getMorphicEvent keyString = '' 


[helicopter move: #left].


getMorphicEvent keyString = ''


[helicopter move: #right].


] to: #keyPress



I hope that helps, welcome to the list and



Happy coding,



Ron Teitelbaum


President / Principal Software Engineer


US Medical Record Specialists


Ron at USMedRec.com





face="Times New Roman">




beginners-bounces at lists.squeakfoundation.org
[mailto:beginners-bounces at lists.squeakfoundation.org] 
style='font-weight:bold'>On Behalf Of Jeff
Sent: Wednesday, November 08, 2006
12:28 AM
beginners at lists.squeakfoundation.org
Subject: [Newbies] Disappointed




I'm pretty disappointed with this list at the moment. My last post,
"beginners questions" talked about how beginners often don't get
their questions answered and pointed out that often when the experts see
an answer, ANY answer, was given they then assume the question was answered,
they don't offer anything more. Now I do appreciate Matthias's honest
to answer the question, so I don't want this to be misconstrued as an attack
him. But he obviously misread it. And, well, once people saw that the
of how to make a wonderland actor move in response to mouse clicks had been
answered, I didn't get any more help. The question I asked was how to move a
wonderland actor with the arrow keys, and I need to do that without the
having the focus. Unfortunately, since it's been taking so many hours for
messages I've tried to send to get posted on here, (I think I had screwed up
joining the list somehow, and redid it so hopefully that problem is solved),
took me a full day to get my question asked and now another full day to
that the answer I got was to a different question. By the by, I've been
spending about 10 hours a day for 5 days now trying to solve this problem.
getting quite frustrating for me and making me want to give up on squeak. 
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