Crate convi

Convi - convenient (but safe) conversion (From-like) traits for Rust

Tired of the pain of casting usize and other types in Rust safely? This crate is here to help.

By enabling cargo features on this crate like this:

convi = { version = "*", features = [ "min_target_pointer_width_32" ] }

you can mark your code as not compatible with architectures with pointer size less than 32 bits. This will enable additional infallible usize conversions like:

use convi::CastFrom;

fn main() {
  let some_u32 = 3u32;
  println!("{}",  usize::cast_from(some_u32));
}

and display appropriate error message if anyone tries to build your code for unsupported architecture.

In addition, for times where you know that your value will always be smaller than the given type, instead of u32::try_from(some_usize).expect("must not fail"), you can:

use convi::ExpectFrom;

fn main() {
  let some_u32 = 3u32;
  println!("{}",  usize::expect_from(some_u32));
}

Zero dependencies, small code, review it yourself.

Traits

CastFrom

Like From, but defined for extra types

CastInto

Like Into but for CastFrom.

ExpectFrom

Expect cast like TryFrom but panicking, instead of returning an error.

ExpectInto

Like TryInto but for ExpectFrom.