Help - The Squeak Environment - 4. What is a programming environment?

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A programming environment is a program to write programs in. Programs are messages to the computer, by which a human user tells a computing machine what to do, for computers respond to programs they can handle by systematic behavior prescribed in the program.

These messages to the computer come by the keyboard or the mouse (and in what follows I will assume you are neither blind nor colorblind: if you are, someone needs to write another sort of tutorial for you).

By means of the mouse you can move a cursor around the screen and click or double click or Alt-click one of three buttons, for it is assumed in Squeak you use a 3-button or at least a 2-button mouse. ("Alt-click " is clicking the mouse while pressing the Alt-key. This is an important message in Squeak, that in most contexts pops up a menu of options.)

So a mouse with its buttons is one basic means to program a computer, and a keyboard another. In both cases something is sent to the computer - in fact a record of: a movement of the mouse, a key touch, a mousebutton click - and in both case the computer (if it works properly, as we also will assume) responds with some behavior. Simple responses are: The cursor is moved, a letter appears on the screen, or something else happens, like resizing a window.

These things you are supposed to know at this point, but it is well to realize that at this point you are communicating with the computer in the sense that you send it messages and it responds in definite ways to definite messages - and that this already is programming as described: Programs are messages to the computer, by which the human user tells a computing machine what to do.

There are more basic means to send messages to a computer - joysticks, microphones, switches - but for the moment we will restrict ourselves to keyboard and mouse commands to the computer, as the most basic examples of programs.

And indeed in fact every more complicated program will also be made up from keyboard inputs or mouse movements and clicks (disregarding other means of input for the moment).

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