w_result

This Rust crate defines WResult, a result type that carries warnings.

Documentation

Sometimes it may be possible for an operation to proceed despite encountering errors. In these cases it's useful to notify the caller about these errors in case they need to act on them. For this, functions can return a WResult.

enum WResult<T, W, E> {
    WOk(T, Vec<W>),
    WErr(e),
}

WResult is similar to Result except that the ok variant carries a vector of warnings alongside it's value. The advantages over just using Result<(T, Vec<W>), E> are

• Clarity.
• Some WResult methods will automatically accumulate warnings from multiple WResults (See for example and and the FromIterator<WResult<..>> impl).

Conversion to Result

Often, the only thing you'll want to do with a WResult is convert it to a Result. WResult provides several methods for doing this that differ in how they handle the warnings:

• WResult::result_log(self) -> Result<T, E> converts to a Result by logging the warnings using the log crate.
• WResult::result_discard(self) -> Result<T, E> converts to Result by discarding the warnings.
• WResult::result_werr(self) -> Result<T, E> converts to Result by treating warnings as errors. If there are warnings, the first warning is returned as the error. This method only exists if the warning and error types are the same type.
• WResult::result_werr_res(self) -> Result<T, Result<W, E>> is similar to result_werr but allows the warning and error types to be two different types.