AppErr

A very thin Any wrapper which does nothing more than state its intended use-case.

lib.rs:

AppErr is a wrapper object intended to hold application-specific errors.

The archetypal use-case is to allow applications that call library runtimes which call application callbacks to allow the application callbacks to return application-specific errors back to itself through the runtime.

In order to lessen the risk of wrapping an unintended type, the AppErr constructor only take in types that implement apperr::Blessed (which is a subtrait of std::error::Error).

Alternatives

There are other ways to solve the same problem, but they are not always feasible.

• Traits can use associated types to declare the application-specific error types.
• A generic parameter can be used to declare the application-specific error type.
• Global variables can be used to store error information.