UsersGuide:Chapter 2:Concepts
From Real Software Documentation
Concepts
There are a few important concepts you will need to understand in order to develop applications with Real Studio. You should also be very comfortable with the graphical user interface your computer uses. If you are not, it would be a good idea to spend some time getting familiar with it before you begin using Real Studio. Otherwise, you may find many of the references in this documentation confusing.
Applications are Driven by Events
Before computers used graphical user interfaces, applications ran by simply executing a series of programming code statements starting with the first statement and ending with the last. Interfaces were all character-based. A menu was just a numbered list of commands that the user selects from to instruct the application to do a task. Most of the time, the application was just sitting there waiting for the user to make up his mind. When the user finally chose a command (perhaps by selecting the number next to the menu item and pressing the Enter key) the application would take whatever action was associated with the chosen command. When the user pressed the Enter key, an event occurred. In other words, something happened to which the application can respond.
Now that desktop computers use a graphical user interface, users have a far more intuitive way to interact with applications. However, one thing hasn’t changed: applications are still driven by events. The difference is that back in the old days there were very few events the application had to worry about responding to. The old-fashioned application was always in a modal state: It only had to respond to the limited number of choices it presented to the user. With a graphical user interface, many more choices and ways of interacting with the computer are available. The user might choose a menu item, click on a button, or type in a field. Also, the applications themselves may cause events to occur that were not directly caused by the user. For example, when a window opens, an event occurs (the window opened). When a window is moved or resized, an event occurs.
Fortunately, Real Studio makes it easy to deal with all of these different events. You can easily find out which events each part of your application’s interface can respond to. Making your application respond to an event is as easy as locating the object that will receive the event, selecting the event, and entering the instructions (using Real Studio’s programming language, Real Basic) you want the object to follow when the event occurs. Later on, you will learn about events in more detail. For now, it’s just important to understand the concept of event-driven programming.
Developing Software with Real Studio
If you have written computer programs using traditional programming languages, you already know that the process of development is three steps: write some code, compile the code (turning the code into something the computer can really understand), and test your application. When you find a problem in your application, you start the process over again. Developing software applications with Real Studio isn’t much different than that. The big difference is how often you go through this process. Compilers for traditional languages can take several minutes or more to compile an application before you can begin testing. Consequently, you spend a lot of time writing code before compiling to avoid waiting for the compiler. Real Studio’s compiler is so fast that you will find you can make a small change to your code and immediately run it to make sure the change you made works as expected. You can also ask Real Studio to check your code for errors before you even try to compile it.
Like traditional programming language compilers, Real Studio’s compiler will stop if it finds a syntactical error in your code and inform you what the error is so you can fix it. But unlike traditional compilers that require you to track down the line of code where the error occurred, Real Studio’s compiler takes you right to the point in your source code where the error occurred.
If you have used traditional programming languages, you will find developing applications with Real Studio to be easier, faster and more fun.
