What is metaprogramming?

"Lisp isn't a language, it's a building material."

– Alan Kay

Any program, regardless of the language used, contains two entities: data and instructions that manipulate the data. The usual flow of a program is mostly concerned with manipulating data. The issue with instructions, though, is that once you write them, it's like they've been carved into stone, and so they are non-malleable. It would be more enabling if we could treat instructions as data and generate new instructions using code. Metaprogramming provides exactly that!

 

It's a programming technique where you can write code that has the ability to generate new code. Depending on the language, it can be approached in two ways: at runtime or at compile time. Runtime metaprogramming is available in dynamic languages such as Python, Javascript, and Lisp. For compiled languages, it's not possible to generate instructions at runtime because these languages perform the ahead of time compilation of programs. However...