maperr
Maperr is a functional programming concept and method used to transform the error value of a result-like type while preserving a successful value. It is commonly applied to data types such as Result<T, E> in Rust or Either<L, R> in other languages, and to similar error-handling abstractions in various libraries. The operation takes a function that maps the error type E to another error type F and returns a new result with the same success type T but with the mapped error F.
Semantics: Given a value r: Result<T, E> and a function f: E -> F, maperr(r, f) yields Result<T,
Examples: In Rust, a closely related method is map_err. For instance, let r: Result<i32, &str> = Err("bad");
Purpose and usage: Maperr is used to convert error types for uniform handling, attach contextual information,
Limitations: Maperr only affects the error branch of the result. If there is no error to map,
Origin: The concept arises from monadic error handling in functional programming. In practice, languages implement it