Author: Codenga 19.04.2022

On the path of your programming adventure, you may come across such a term as Domain-Specific Language (DSL).

In this article we will try to explain this interesting concept. At the same time, we will give some examples of languages considered as domain-specific languages.

Two main language groups

We can roughly divide programming languages into two main groups:

• General-purpose languages
• Domain-specific languages, specific to a particular domain.

When it comes to general-purpose languages, we are dealing with languages that are universal. You can use them to create all kinds of software. We can have endless examples of such languages: Python, Java, JavaScript, C++, C#, etc. These are the languages that immediately come to mind when we talk about programming.

Domain-specific languages, on the other hand, as the name suggests, are specialty languages. They are used to work with a specific domain and are usually not suitable for developing broad, general-purpose software.

The lines between these two groups are quite blurred. Sometimes you may encounter a general-purpose language that is used primarily in one selected area.

You can also find examples of DSL-type languages that have applications that extend beyond one field. To be honest, it is not that important. Practice is much more important than academic definitions.

HTML

HTML is a language for building web pages. You could say that HTML is an example of a domain-specific language. Why?

Because we use it mainly to build websites, in other words in one particular area. With HTML it is hard to create an advanced 3D game or a desktop application. It is a language with strictly defined applications.

It could be argued that almost anything is created using modern HTML. There is a lot of truth in this. There are countless examples of games, mobile apps, and other HTML-based programs. Here, however, you need to remember one key thing.

These projects were all built using a combination of HTML and JavaScript. HTML alone would not be enough to build a functional application because it does not have such capabilities. All functional elements are therefore built using a general-purpose language which is JavaScript. HTML is used only to build content and structure because it was created for this purpose.

SQL

SQL is another example of a domain-specific language. We use it to write database queries. So we operate in one specific domain.

We cannot use SQL to build a complete application. Instead, we can use its specialized capabilities to write queries, and to work with a database. So SQL does one specific thing. It is used in one specific area.

Other examples

SQL and HTML are examples of very popular domain-specific languages. Of course, they are not the only ones.

It could be argued that CSS is such a language. We use it to write styles for web pages. That is, we are dealing with a specialized language that is used to write one particular thing.

We also have various specialized languages like Gawk used to process text in the terminal. Or Make for describing the process of building application files. Such examples could be multiplied almost endlessly. Practically every domain has its own, sometimes very niche, domain-specific languages. This is a very broad topic.

As we wrote earlier, sometimes the boundaries between general-purpose languages and domain-specific languages (DSLs) are very fluid.

The most important thing to realize is the very concept of a domain-specific language. Which is, one that inherently has applications limited to one particular domain.