在 src/lib.rs
我有以下内容
extern crate opal_core;
mod functions;
mod context;
mod shader;
然后在 src/context.rs
我有这样的东西,它试图从 src/shader.rs
导入符号:
use opal_core::shader::Stage;
use opal_core::shader::Shader as ShaderTrait;
use opal_core::GraphicsContext as GraphicsContextTrait;
use functions::*; // this import works fine
use shader::*; // this one doesn't
pub struct GraphicsContext {
functions: Gl
}
fn shader_stage_to_int(stage: &Stage) -> u32 {
match stage {
&Stage::Vertex => VERTEX_SHADER,
&Stage::Geometry => GEOMETRY_SHADER,
&Stage::Fragment => FRAGMENT_SHADER,
}
}
impl GraphicsContextTrait for GraphicsContext {
/// Creates a shader object
fn create_shader(&self, stage: Stage, source: &str) -> Box<ShaderTrait> {
let id;
unsafe {
id = self.functions.CreateShader(shader_stage_to_int(&stage));
}
let shader = Shader {
id: id,
stage: stage,
context: self
};
Box::new(shader)
}
}
问题是语句 use shader::*;
给出了错误 unresolved import。
我正在阅读文档,他们说 use
语句总是从当前 crate (opal_driver_gl
) 的根开始,所以我认为 shader::*
应该导入 opal_driver_gl::shader::*
但它似乎没有这样做。我需要在这里使用 self
或 super
关键字吗?
最佳答案
请注意,use
的行为已从 Rust 2015 更改为 Rust 2018。参见 What are the valid path roots in the use keyword?了解详情。
使用rust 2018
要在同一级别上导入模块,请执行以下操作:
random_file_0.rs
// Note how this is a public function. It has to be in order to be
// usable from other files (in this case `random_file_1.rs`)
pub fn do_something() -> bool {
true
}
random_file_1.rs
use super::random_file_0;
#[test]
fn do_something_else() {
assert!(random_file_0::do_something());
}
或替代random_file_1.rs:
use crate::random_file_0;
#[test]
fn do_something_else() {
assert!(random_file_0::do_something());
}
lib.rs
mod random_file_0;
mod random_file_1;
参见 Rust By Example有关更多信息和示例。如果这不起作用,这里是它显示的代码:
fn function() {
println!("called `function()`");
}
mod cool {
pub fn function() {
println!("called `cool::function()`");
}
}
mod my {
fn function() {
println!("called `my::function()`");
}
mod cool {
pub fn function() {
println!("called `my::cool::function()`");
}
}
pub fn indirect_call() {
// Let's access all the functions named `function` from this scope!
print!("called `my::indirect_call()`, that\n> ");
// The `self` keyword refers to the current module scope - in this case `my`.
// Calling `self::function()` and calling `function()` directly both give
// the same result, because they refer to the same function.
self::function();
function();
// We can also use `self` to access another module inside `my`:
self::cool::function();
// The `super` keyword refers to the parent scope (outside the `my` module).
super::function();
// This will bind to the `cool::function` in the *crate* scope.
// In this case the crate scope is the outermost scope.
{
use cool::function as root_function;
root_function();
}
}
}
fn main() {
my::indirect_call();
}
使用rust 2015
要在同一级别上导入模块,请执行以下操作:
random_file_0.rs
:
// Note how this is a public function. It has to be in order to be
// usable from other files (in this case `random_file_1.rs`)
pub fn do_something() -> bool {
true
}
random_file_1.rs
:
use super::random_file_0;
#[test]
fn do_something_else() {
assert!(random_file_0::do_something());
}
或替代random_file_1.rs
:
use ::random_file_0;
#[test]
fn do_something_else() {
assert!(random_file_0::do_something());
}
lib.rs
:
mod random_file_0;
mod random_file_1;
这是 Rust By Example 之前版本的另一个例子:
fn function() {
println!("called `function()`");
}
mod my {
pub fn indirect_call() {
// Let's access all the functions named `function` from this scope
print!("called `my::indirect_call()`, that\n> ");
// `my::function` can be called directly
function();
{
// This will bind to the `cool::function` in the *crate* scope
// In this case the crate scope is the outermost scope
use cool::function as root_cool_function;
print!("> ");
root_cool_function();
}
{
// `self` refers to the current module scope, in this case: `my`
use self::cool::function as my_cool_function;
print!("> ");
my_cool_function();
}
{
// `super` refers to the parent scope, i.e. outside of the `my`
// module
use super::function as root_function;
print!("> ");
root_function();
}
}
fn function() {
println!("called `my::function()`");
}
mod cool {
pub fn function() {
println!("called `my::cool::function()`");
}
}
}
mod cool {
pub fn function() {
println!("called `cool::function()`");
}
}
fn main() {
my::indirect_call();
}
关于import - 如何从同级模块导入?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/30677258/