gara

This comment is misleading &| misinformed. Sum types are built-in [1] for formal parameters. `nil` is only for `ref|ptr` types. In much code you can just use stack allocated value types and there is neither GC concern nor nil concern, but there is also a mode to help: https://nim-lang.github.io/Nim/manual_experimental_strictnot... Nim has an easy-ish to use Lisp-like syntax macro system where you just receive & process an AST. So, to do the rest you can make libraries adding the feature without relying upon upstream compiler: such as https://github.com/beef331/sumtypes for variables with sum types or pattern matching libs like https://andreaferretti.github.io/patty/ | https://github.com/alehander92/gara.

Yes. ADT are case objects: they are widely used. https://nim-lang.org/docs/tut2.html#object-oriented-programm... There are some macros for easier generation: https://github.com/andreaferretti/patty#constructing-variant... There are pattern matching libs: pattern matching is implemented on top of metaprogramming. General pattern matching: the original https://github.com/andreaferretti/patty https://github.com/alehander42/gara (disclaimer: my lib) patty and gara should eventually combine into a single lib: including probably the current gara matching DSL(inspired by patty) and patty's variant DSL in the same place. AST pattern matching: optimized for macros, nice error reporting https://github.com/krux02/ast-pattern-matching

I see Nim lately made some cleanup in the macros module. Thats great. Macros now are much more easy to wrap my head around and I have already produced my first usable macro: https://github.com/b3liever/protocoled. Also others are trying to use the new caseStmt macros: https://github.com/alehander42/gara. Great stuff!