[英]How do I import from a sibling module?
在src/lib.rs
我有以下
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)
}
}
问题是该语句use shader::*;
给出错误unresolved import 。
我正在阅读文档,他们说use
语句总是 go 从当前板条箱( opal_driver_gl
)的根目录开始,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?
谢谢,如果你能帮忙。
需要注意的是行为use
已经从2015年锈变更为2018年锈病见什么都在使用关键字的有效途径根源是什么? 详情。
要在同一级别导入模块,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());
}
库文件
mod random_file_0;
mod random_file_1;
有关更多信息和示例,请参阅Rust By Example 。 如果这不起作用,这是它显示的代码:
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();
}
要在同一级别导入模块,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;
以下是 Rust By Example 先前版本的另一个示例:
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();
}
从目录/子目录导入模块实际上有点棘手。 今天花了 3 个小时来完全理解这一点,因为该文档缺少文档,否则 Rust 的文档非常好。 我创建了一个示例项目来展示如何做到这一点。 https://github.com/amitstefen/rust_modules_example
这两个文件是关键-
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