try-insert-ext

This library provides extension traits for std types, adding or_try_insert_with (or equivalent) methods for Option, map Entry types, and HashSet. These act similarly to or_insert_with methods, but taking a function that returns a Result, and inserting only if the function returns Ok, otherwise returning the Err.

lib.rs:

Provides extension traits for Option and map Entry types, adding try_insert methods. These methods take possibly empty containers, and if empty, run an initialization function. If this function errors, an error is returned. Otherwise, the initialized value is returned.