position

position provides a Position struct, representing a source code position, as well as a convenient here!() macro for creating a position corresponding to the location where here!() was invoked:

use position::{here, Position};
let p: Position = here!();
assert_eq!(p.file(), "src/lib.rs");
assert_eq!(p.line(), 5);
assert_eq!(p.column(), 19);
assert_eq!(p.module_path(), "rust_out");
assert_eq!(p.to_string(), "src/lib.rs:5:19");

If position is compiled with the location feature, on by default, Position implements oi::Location, so it can be used with oi::ErrAt::err_at:

# #[cfg(feature = "location")]
# {
use std::{io, fs::File};
use oi::ErrAt;
use position::{here, Position};

let result: oi::Result<File, io::Error, Position> =
  File::open("foo.txt").err_at(here!());

assert_eq!(
  result.unwrap_err().to_string(),
  "src/lib.rs:11:32: No such file or directory (os error 2)",
);
# }