Beej's Bit Bucket
a day ago
- The author implements a Reverse Polish Notation (RPN) calculator in Rust, explaining the stack-based evaluation process.
- Initial code uses command line arguments, parse/match, and unwrap() for error handling, which is improved by direct iterator usage and skipping the program name.
- Discussion of Rust's collect() method, type inference, and turbo fish notation is provided.
- Token parsing is done by attempting to parse as i64; if that fails, the token is checked against operators.
- Error handling is refined by replacing unwrap() with if let patterns and tuple assignments, eventually returning a Result from a generic math_op function.
- The final code uses closures (FnOnce) to pass operator logic, resulting in cleaner code with proper error propagation.
- The article concludes with a reference to the Shunting-yard algorithm for infix-to-postfix conversion.