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notes-2-09

Notes:
  • Everyone in class should email Professor Pitt with what changes they made to the Squeak How-To. Students were required to change two topics to level 3 or level 3X.
In class we students showed two supplies from the supplies bin that they were clueless about and use them in Squeak.
  • Book: You can drag objects into book and it automatically embeds it into the page (no need to explicitly state "Embed").
  • ScrollBar: There are actually three objects in the scroll bar. The rectangular bar, the scroll box, and another box which shows the scroll box previous state. NOTE: "Mouse up" only applies to the top layer of objects.
  • Clock object does nothing besides showing time. Numbers in clocks are strings which can be picked up, but clock hands cannot be selected or picked up.
  • You should be able to drop objects into new projects, but it did not seem to work when Professor Pitt tried it.
  • Event recorder: Can be used for presentations.
  • We also had a discussion on how a Book can be used as array and/or linked list.
  • We saw how to use "Use as Page Prototype" for a book
There was also a discussion on how programming in Squeak changes your way of thinking about programming.
  • Text based code - typing certain pieces of code might not makes sense in text based code, but you are still allowed to type it in.
  • Squeak - you cant make scripts in squeak if it wont work. Squeak wont allow it.
The next discussion was about the particle simulation - when particles collide, particles split
One student found a problem - when particles colllide and you create a new particle at the moment of collision, the copied particle would instantly collide with the parent particle, causing an autmatic collision. A delay is needed for this to work right.

One way we found to make a delay:
  • "Fires per tick" is the number of times script runs per tick, this can be changed. You can change this so that the script will run on a delay.
  • Tick Rate - time rate of tick, i.e. .25 seconds per tick or 8 seconds per tick
  • You can change tick rate by holding down Clock next to script
  • Another note: Alt + Period = User interrupt
GAME OF LIFE (math game not baord game) : made by John Conway
Complexity out of simplicity. Read more about it here:
http://www.math.com/students/wonders/life/life.html
http://www.ibiblio.org/lifepatterns/

Bubblesort
We tried to use a slow downed tick rate for bubblesort so the script doesnt run as quickly as it was. The problem with this is that the bublesort script was coded recurslively instead of iteravly. What does a recursive code mean if it only runs once (answer: nothing). Coding bubblesort with a slow down tick rate could have worked if bubblesort was coding iteravily.

Projects: What kind of projects should we as a class be thinking of?
  • We need to make projects that teach CS concepts such as:Binary numbers, AI, teach conditionals...
  • How to use this technique of programming within Squeak?
  • People should be doing things in Squeak but still learn concepts.

Next week come prepared with concrete ideas of projects or pieces of projects to bring next Wednesday Feb 16.

Announcements - Kathleen has workshops about how to use Squeak to teachers in Urbana-Champaign. Students may help Kathleen with helping BEGINERS learn Squeak.
  • Parkland - the end of this month and early next month: Local Squeakfest
  • Squeak nite April 26 in the Planetarium.