Alice3 Chapter 3

Code editor's method panel

(immediately below the Object selector) has two tabs, one containing Procedures (procedural methods) and the other containing Functions (functional methods).

Scene class

-Open it by clicking the Scene tab in the right window of the scene editor -a blueprint that tells Alice (1) what actions (procedures and functions) a scene can perform and (2) what components (properties) a scene contains

The scene class always has two built in properties:

Ground and camera

Parameter

a piece of information required to perform a task

Argument

a value sent to a parameter

Keyword

a word that has a special meaning in a programming language

Procedural methods

actions that can be performed by or on an object

Functional methods

actions that compute or retrieve information about an object.

Properties section

contains the declaration statements for the objects belonging to a scene

Code statement

created (written) by dragging a tile into the editor and supplying any information (data) needed to perform the action.

Call a method

means to tell the computer at runtime to perform the action defined by that procedure.

When you drag a procedure tile into the editor tab, Alice will often ask for some information in a dropdown menu. This is because many procedures have one or more ______.

paramenters

Run button

Test a program (code) by clicking the it. When the it is clicked, the program creates a runtime window in which the initial scene is displayed. When the scene is displayed we say the scene has been activated. When the scene is activated, the code statements in myFirstMethod are executed.

Syntax

set of rules that govern the arrangement of words, phrases, and symbols in code statements.

Active method

The code editor tab that displays on top of the other tabs. It is the method currently open for editing.

Active class

the currently open class

General format (Syntax) of an Alice statement

the name of an object followed by the name of a method that is to be performed

Implementation

the process of translating a design algorithm into program code

When you add objects to the Scene,

they become properties to the Scene

Do in order

this, at the beginning of myFirstMethod, tells Alice to execute the code statements in sequence, one after the other. The execution of a method (procedure or function) is referred to as calling it.

Detail parameter

Some procedures have parameters that have default values that are called detail parameters. If we do not specify a value for a detail parameter, Alice will use the default value. For example the duration is a detailed parameter with a default value of one second. If we do not specify a different duration value (argument) Alice will perform the procedure in one second.

Object Selector Box

Box on the left side of the screen in the code editor that you use to select the Object that you wish to work with.

When you select an object with the object selector box, the ____________ contain tiles that represent actions that the selected object "knows" how to perform.

Procedures and Functions tab

Method

Procedures and functions are two different forms of it