Classes were introduced with 4D v18 R3. They allow you to organize your business logic and separate it from the UI part more quickly.
Classes are composed of several functions of varying lengths, so it’s not always easy to find the function you want to modify, or to move from one function to another. You can use the explorer, which displays classes and functions, but when you’re coding in the editor window, you don’t want to waste time changing windows.
With 4D v19 R4, the list of functions in your class is displayed in the code editor toolbar, allowing you to easily jump to a specific function.
With the introduction of classes in the 4D environment, the need to store your data in objects, and especially blobs, has increased. That’s why 4D v19 R2 lets you encapsulate blobs in objects.
Beyond the storage aspect, since the blob object is a reference type, your performance in terms of memory occupation and speed will be greatly improved.
Using $1, $2, and $n variables in your code not only makes the code less readable, it can also increase confusion since the human brain can find it difficult to remember what these variables correspond to. The solution is to create a variable with an understandable name and assign it the value of $1, $2, or $n.
4D v18 R5 has good news, you can now name your parameters when declaring:
- a project method,
- a trigger
- a database method
- a form method
- a constructor of a class
- a function of a class.
Let’s see how!
by guest author Tiran Behrouz, 4D developer (Vancouver, Canada)
The introduction of ORDA in 4D v17 was a game-changer. Now with the introduction of classes in 4D v18 R3, we will witness a paradigm shift in 4D programming. We can now take advantage of object-oriented programming concepts such as polymorphism, composition, and inheritance to write our own class libraries. In this video, I demonstrate how to code a simple TimeStamp class using 4D and ORDA.
By now you’re aware of the availability of ORDA classes. In this blog post, you’ll learn a few handy tips to get the most out of them!
Let’s see it in action!
In a previous blog post, we introduced you to the world of ORDA data model classes. Now it’s time to get our hands dirty and learn more!
You already know that ORDA’s structure (datastore, dataclass, entity, entity selection) is made up of objects. But they’re not just objects, they’re strongly-typed objects linked to specific ORDA classes. This means that you can write functions to hide the complexity of your data’s physical implementation.
ORDA was a revolution with 4D v17. It opened a whole new world of possibilities and took you to another programming dimension. A dimension where you can easily develop applications using an object-oriented approach.
We didn’t stop there! We continued to add enhancements to ORDA through a set of features in each subsequent feature release. Now with 4D v18 R4, we’re thrilled to be going another step further with the availability of ORDA data model classes. Classes dedicated to your data model.
This will greatly elevate your code. Your applications can now easily expose services, be more manageable and easier to maintain, and seamlessly integrate with other applications.
This is another big feature made possible thanks to the projects!
In a previous blog post, we introduced a very important concept in object-oriented programming: Classes. Now we’ll go through another core concept: Inheritance, the mechanism that allows a class to acquire the behavior of another class.