2. Dividing the Story (methods)

The programs you use every day contain thousands or millions of lines of code (instructions which are tiles in the Alice programming language). The authors of those programs need tools to help them manage that complexity. Much of the power of computing comes from these complexity managing tools.

While our stories and the programs that implement them won't be getting as large as that, they'll get big enough very soon to need similar tools. You'll find that appreciating how computing people can handle this complexity is useful and is also something you will be able to recognize in programs and technology in the world around you. More on that later...

Things you will learn in this module:

1. We use methods to break up a large amount of code into smaller, more manageable pieces (note, this doesn't change the overall amount of code, it just changes how it is organized).
2. If you want your methods to be executed when you hit play, you need to call the methods in the method world.my first method (that's the one we've been working in up to this point).
3. We will use methods in this module primarily for the benefit of the human (aka you). Breaking up programs is one way we use abstraction to manage complexity in computing. Computers can do some very complex things. Humans need to use abstraction to help them manage thinking about all the instructions they give the computer in their programs.

Vocabulary for this module:

Abstraction: The process of hiding the complexity or detail of an operation while still presenting its essential characteristics. Putting the many instructions that may carry out a given operation into a method with a name that represents the operation is an example of abstraction.

Call a Method: The place in a program where you tell the computer to go execute a method (and it jumps to where that method is defined and then comes back).

Execute/Play: Tell the computer to execute instructions you have given it (for now, in world.my first method).

Method: A named collection of instructions that naturally belong together to do some thing/task (e.g., Freak Out).

Method Definition: The place where you describe/put the instructions that should be executed when this method is called (in Alice, each method definition is in a different "tab" in the program area).

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