imports.md

% Imports [FIXME: needs RFC]

The imports of a crate/module should consist of the following sections, in order, with a blank space between each:

• extern crate directives
• external use imports
• local use imports
• pub use imports

For example:

// Crates.
extern crate getopts;
extern crate mylib;

// Standard library imports.
use getopts::{optopt, getopts};
use std::os;

// Import from a library that we wrote.
use mylib::webserver;

// Will be reexported when we import this module.
pub use self::types::Webdata;

Avoid use *, except in tests.

Glob imports have several downsides:

• They make it harder to tell where names are bound.
• They are forwards-incompatible, since new upstream exports can clash with existing names.

When writing a test submodule, importing super::* is appropriate as a convenience.

Prefer fully importing types/traits while module-qualifying functions.

For example:

use option::Option;
use mem;

let i: isize = mem::transmute(Option(0));

[FIXME] Add rationale.