Writing complex macros in Rust: Reverse Polish Notation

What this post added

This post introduces a detailed tutorial on writing complex macros in Rust, using Reverse Polish Notation (RPN) as a practical example. It demonstrates how to leverage Rust's macro system for compile-time evaluation by converting RPN expressions into infix notation. The tutorial covers matching tokens with `tt`, recursive macro invocation for state management (stack simulation), handling operators, and basic error handling strategies using `trace_macros`. It provides runnable code examples and links to playgrounds.