4D v16 R6 introduces a new concept of communication between processes: shared object and shared collection variables! They are a solution so you can avoid using interprocess variables (which can’t be used in multi-thread mode). Thanks to this, you will be able to easily share information between preemptive processes.
Quite frankly, we love objects. 4D Write Pro uses objects as the input/output of commands and functions to manipulate documents, text, paragraphs, etc. In this blog post, we’ll show you four different ways to use objects with 4D Write Pro.
In 4D v16 R4, we enriched object commands so you can validate JSON objects. 4D v16 R5 is going even further by introducing the support of JSON pointers. Great – but what is a JSON pointer and what can I do with it?
Just like you don’t store company details for each employee in a database record (using a link to the company record instead), it can be really useful to structure a JSON document with parts that can be reused in a number of places.
For instance, let’s take an example of a website order; the customer enters the shipping address and designates the billing address as the same. Instead of duplicating the address information, we can define the shipping address as a reference to the the billing address.
With 4D v16 R4, we introduced Object Notation which is a great enhancement to the 4D language: your code is fast, flexible, efficient and elegant! This feature created a lot of interest on the 4D forums and we received a lot of feedback from our customers highlighting situations when there were undefined values making the code challenging to write.
With 4D v16 R5, we have taken your feedback into account and have simplified the use of undefined properties and values with Object Notation.
Wouldn’t it be great if you could just open a form and pass it some parameters to initialize your form objects? What about being able to also get the data back to process, after it’s been modified by the user? 4D v16 R5 makes your coding so much easier by greatly simplifying communications with forms.
Until now, when you wanted to display data (not coming from the database itself, but computed or external) to multiple users, you had two options: either write complex code to handle data display in multiple processes, or create as many forms as necessary with a bunch of global variables. But you know that global variables are not an optimized way of coding, from a memory point of view.
So get rid of your complex code and global variables! With 4D v16 R5 you can just bind an object to your form and use it internally with the new Form command. Painless…and powerful!
From 4D v16 R4, we have added the support of pictures in object attributes. For example, if you use an object to exchange settings or data between methods, forms or processes, now, you can also pass an icon or a picture in this object. You don’t need anymore to temporarily save the picture on disk.
This new type can be used like any other object attribute type: you can use, get and set pictures in objects. You can also use the controls of the picture theme.
4D introduces a new Null type to ease the management of objects and collections. Thanks to the null value, you can represent a missing value and easily verify if your object or collection is correctly set.
4D v16 R4 introduces a new type of variable called Collection. What are these variables intended for? Like Objects or BLOBs, collections can be used to hold almost any kind of variable types like texts, numerics, booleans, objects and even other collections. The good thing is that, all these variables types previously mentioned can be mixed inside the same collection, where arrays must always contain the same type of elements!
We use more and more the JSON format. For example, to save settings in a file, to store software configuration, or to exchange client-data on the web with other servers.
How can you validate that the received data is in the expected format? How can you validate that all the necessary information is actually present? How can you do this validation without writing a tiresome method for each type of JSON format?
Simply by writing a JSON schema and use the JSON Validate new command!
With the object notation, available as a preview in 4D v16 R4, your code is simpler to write, easier to read and more natural to think. That is true. But did you really see the full potential of the object notation?
Before 4D v16 R4, when you wanted to create a detail form to enter contact information from an object field, you had no choice but to write an expression like OB GET ([CONTACT]Info; “City”) in the variable data source. You could retrieve the attribute value, but it was not possible to change it. Moreover, you had to write a loadRecord method with the OB GET command for each attribute and a saveRecord method with the OB SET command for each attribute.
What does object notation change in this scenario? From 4D v16 R4, you just write [CONTACT]Info.City in the variable data source! This variable is available in Read/Write mode. OB GET and OB SET commands are no longer necessary. That’s it! Now you see the full potential.
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