> This is useful for compiler programmers, or maybe also those writing source code analyzers/optimizers, but is that it?
It is also useful for anyone wanting to implement language-level features as simple libraries. Someone else brought up Nim here: it's a great example of what can be done with metaprogramming (and in a non-Lisp language) as it intentionally sticks to a small-but-extendable-core design.
There's macro-based libraries that implement the following, with all the elegance of a compiler feature: traits, interfaces, classes, typeclasses, contracts, Result types, HTML (and other) DSLs, syntax sugar for a variety of things (notably anonymous functions `=>` and Option types `?`), pattern matching (now in the compiler), method cascading, async/await, and more that I'm forgetting.
It is also useful for anyone wanting to implement language-level features as simple libraries. Someone else brought up Nim here: it's a great example of what can be done with metaprogramming (and in a non-Lisp language) as it intentionally sticks to a small-but-extendable-core design.
There's macro-based libraries that implement the following, with all the elegance of a compiler feature: traits, interfaces, classes, typeclasses, contracts, Result types, HTML (and other) DSLs, syntax sugar for a variety of things (notably anonymous functions `=>` and Option types `?`), pattern matching (now in the compiler), method cascading, async/await, and more that I'm forgetting.
https://github.com/ringabout/awesome-nim#language-features