Use

Use allows you to bring names in modules into your current scope so they can be used without prefixing.

sys::net::subscribe(...); // call subscribe in the sys::net module
use sys::net;
subscribe(...) // same function

Use is valid anywhere expressions are valid

let list = {
  use array;
  map([1, 2, 3, 4, 5], |x| x * 2)
};
list

will print [2, 4, 6, 8, 10]

let list = {
  use array;
  map([1, 2, 3, 4, 5], |x| x * 2)
};
map(list, |x| x * 2)

will not compile, e.g.

$ graphix test.gx
Error: in file "test.gx"

Caused by:
    at line: 5, column: 1 map not defined

Use paths are always absolute — they are resolved from the root of the module tree, not relative to the current module. For example, if you are inside the sys::net module and want to use the sys::time module, you must write use sys::time, not use time.

// inside sys::net
use sys::time;     // correct — absolute path

A submodule can reference bindings from its parent directly, but only if the mod declaration comes after those bindings in the parent’s interface file.

Use shadows earlier declarations in it’s scope. Consider,

let map = |a, f| "hello you called map!";
let list = {
  use array;
  map([1, 2, 3, 4, 5], |x| x * 2)
};
(list, map(list, |x| x * 2))

prints

$ graphix test.gx
([2, 4, 6, 8, 10], "hello you called map!")