Alice Workshop
Implementation
Algorithm  Code
World.my first method
Control blocks
Statements (methods, data, more)
Copyright 2011
Wanda Dann, Steve Cooper, Don Slater
Next Step
Problem Statement
Understand
the
problem
Test the
code
Design a
solution
Implement
the design
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Wanda Dann, Steve Cooper, Don Slater
Load World
Why start with a standard world for active
learning?
Load from: Presentations/Worlds
3-GoodVibrationsSetUp.a2w
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Wanda Dann, Steve Cooper, Don Slater
Do in order
By default, statements in the code are
performed in order, but you can also create
a Do in order code block.
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Control Statements
Alice has two fundamental control
statements
 Do in order
• perform the actions in sequence
 Do together
• perform the actions simultaneously
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Wanda Dann, Steve Cooper, Don Slater
First action statement
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1. Select object
Start by selecting an object in the object
tree (or click on the object in the scene)
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Wanda Dann, Steve Cooper, Don Slater
2. Select methods tab
In the details panel
Tabs



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Properties 
values of object
properties
Procedures 
methods that
perform an action
Functions 
methods that
return a value
3. Find method tile
Scroll down in methods tab
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Wanda Dann, Steve Cooper, Don Slater
4. Drag-n-drop
Select data from drop-down menu…
“turn to face” needs a target object
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Wanda Dann, Steve Cooper, Don Slater
Next Step
Problem Statement
Understand
the
problem
Test the
code
Design a
solution
Implement
the design
Copyright 2011
Wanda Dann, Steve Cooper, Don Slater
Play (Run)
Click the Play button
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Wanda Dann, Steve Cooper, Don Slater
World.my first method
When Play button is clicked, the world’s
my first method is executed
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Modify
Alice allows some optional information to
modify how an action is performed.
 By default a statement in Alice runs in 1 second. The
duration can be changed using more…
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Wanda Dann, Steve Cooper, Don Slater
Next action
Actually, several actions
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Wanda Dann, Steve Cooper, Don Slater
Method?
No “vibrate” tile?
 Method tiles built-in to Alice are
simple actions
 Some models have complex
actions defined, e.g., walk
 For other complex actions, we
may create our own
Copyright 2011
Wanda Dann, Steve Cooper, Don Slater
Decompose
How can we create our own “vibrate”
method?
Decompose a complex action into simple
actions
garfield.vibrate
do together
play vibrating sound
do in order
garfield move up a short distance, quickly
garfield move down same distance, quickly
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Create a new method
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Name the method
Name should begin with a lowercase letter
and have no spaces (use camelCase, if
needed)
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garfield.vibrate
New method tile and editor tab
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Number pad
Select “other” for number pad entry
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Duplicate
Hold Ctrl(Alt on Mac) and drag statement
down to create a duplicate
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Modify
Click drop-down menu to select a different
(argument) value
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Test
Warning???
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Call the method
Alice must be given an instruction to
perform the actions defined in the method.
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Test
Does the action performed by garfield
appear to be a vibration?
Why or why not?
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Revise Design
An object that vibrates is oscillating in a
rhythmic repetition
We need to repeat the action several
times
garfield.vibrate
do together
play vibrating sound
repeat 5 times
do in order
garfield move up a short distance, quickly
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Wanda Dann, Steve Cooper, Don Slater
garfield move down same distance, quickly
Loop
Drag in Loop control tile and select
“5 times”
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Loop control block
Drag code statements into the Loop
control block
A block of program code that repeats a
counted number of times.
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Test
Does the action performed by garfield
appear to be a vibration?
Why or why not?
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Wanda Dann, Steve Cooper, Don Slater
Revise #2
Play a sound at the same time….
garfield.vibrate
do together
play vibration sound
loop 5 times
garfield moves up a short distance, quickly
garfield moves down same distance, quickly
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Import sound
World properties panel
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Imported file, timing
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Do together
Drag in do together code block
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Play sound
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Nested control blocks
Do in order inside do together
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Test
Are sound and vibration in sync?
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Wait
Useful for synchronizing sound and action
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Save
Be sure to save the world every half-hour,
or so…
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Textbook
More information
 Coding
• Chapter 2, Section 2
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