Zig has a special / compiler-known ADT for "value OR error". This is similar to Result<T,E> in Rust. Or in C++, e.g., folly::Expected<T,E>. The Zig one is so

Zig has a special / compiler-known ADT for "value OR error". This is similar to Result<T,E> in Rust. Or in C++, e.g., folly::Expected<T,E>. The Zig one is so special and compiler-blessed that there is special syntax for defer blocks that only run when the function return is an error variant of that result ADT -- errdefer.