In imperative programming, it is developer responsibility because s/he directly manages the control flow. Understanding behaviors of both runtime eases to solve the dilemma and gives concrete practices. However, in declarative programming, since the system is accepting declarative statements, the runtime is fully in charge. The definition of declarative programming is widely used. However, the important point here is to understand of the runtime because its specifications define system behaviors. Declarative programming is an enabler of abstraction. This week, I finally found two mnemonics that work for me and I'm happy to share them in hope that they would work for you as well: Mnemonic one: … For me, one of such struggles has been remembering declarative and imperative programming — which one is which. The imperative property is the dual, where semantics are inconsistent under composition and/or can be expressed with variations of sets of statements. For example: In this case, b = a + 1 is a declarative statement that whenever a changed, the runtime should update b along with, so that, b becomes 3. Some repetitive works might be automated within methods/tactics like OOP, AOP, etc., but at the end, it is a thing that developer have to manage and configure regardless. However, if you defined aspect, it automatically updates, so that, it shortcuts, but the theory stays the same as it requires developers to code and configure. Let’s start with imperative runtime, which executes code lines as directed, and a developer is fully in charge of the flow. Declarative programming allows you to say "I want this and I don't care how I get it" while imperative programming requires you to define each and every step. Declarative runtime works with intermediate language that they are mostly considered declarative statements as abstraction of willing (Not literal statements). However, in imperative programming developer has to run something like a = 5; updateB(a); updateC(b); assuming functions contains the logic. heavily dominates programming languages. I've read a couple of posts and definitions and while they made perfect sense, I'd have to google it again after half a year. For example, you have an object, and every single time when its property is changed, you are to change update time when happened, so that, you have to call updateTime() function. Clearly, popularity of declarative and functional programming is arising, but as of today, imperative programming including its libraries, tooling, etc. Pattern Matching in TypeScript with Record and Wildcard Patterns, Dockerfile : Best practices for building an image, An Upgrade From the Venerable ATtiny85 to the New AVR 1 Series — An ATtiny412 Tutorial, How I Got AWS Certified While Having a Life, Choosing the Right Git Branching Strategy for Your Team, Lloyd, J.W., Practical Advantages of Declarative Programming. In contrast, declarative programming merely declares what to do to get the desired result, but not how to compute it. Imperative programming is a programming paradigm that uses statements that change a program’s state. Both programming styles play significant roles while programming. The key difference between Declarative and Imperative programming is that Declarative programming focuses on what the program should accomplish while Imperative programming focuses on how the program should achieve the result. From an engineering stand point, it is not a best practice if hard coded everywhere because this increases number of code lines along with complexity, may end up with serious maintainability issues. According to The Information: Declarative programming is a programming paradigm … that expresses the logic of a computation without describing its control flow. It is used even more than the definition of the imperative one. It would also be interesting to tell what declarative programming is. We can use more advanced case like including if statement: Now in this case, when a = 5 called, the runtime automatically aligns rest with calling b = a + 1 and if( b > 5 ) { .. } statements. In imperative programming, it is developer responsibility because s/he directly manages the control flow. Nucleoid is open source (Apache 2.0), a runtime environment that allows declarative programming written in ES6 (JavaScript) syntax. Since statements are declarative, the runtime provides logical integrity and persistency as hiding technical details. Control flow is probably the most important parameter in order to distinguish both because at the end of transaction, logical/data integrity cannot be broken, so that, side effects of execution requires to align with rest of the system. Imperative programming is an inhibitor of abstraction. Imperative programming is a programming paradigm in which a sequence of statements to determine how to reach a certain goal. Declarative Programming is programming with declarations, i.e., declarative sentences. Though imperative programming is easier to reason about for beginners, declarative programming allows us to write more readable code that reflects what exactly we want to see. A programming paradigm is used to classify a programming language depending on the feature. Declarative programming allows you to announce what you want to be done. If we run the same statements in imperative runtime like JavaScript engine, the result will be different: Because a in b = a + 1 only represents memory block location, so that, updating a with 2 doesn’t impact b itself. In the last example above, dependency flow goes like c -> b -> a so, at the time a is changed, the runtime automatically reruns b = a + 1 as well as if( b > 5 ) {..}.