add module

rust-examples/Cargo.toml

@@ -3,7 +3,7 @@ name = "rust-examples"
 version = "0.1.0"
 authors = ["梦境迷离 <liguobin@growingio.com>"]
 edition = "2018"
-
+#build = "build.rs" 构建前操作
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]

rust-examples/src/main.rs

@@ -7,11 +7,13 @@ use crate::custom_types::*;
 use crate::flow_control::*;
 use crate::formatted_print::*;
 use crate::functions::*;
+use crate::modules::*;
 use crate::primitives::*;
 use crate::types::*;
 use crate::variable_bindings::*;
 
 pub mod formatted_print;
+pub mod modules;
 pub mod functions;
 pub mod flow_control;
 pub mod closures;
@@ -31,4 +33,5 @@ fn main() {
     flow_control();
     functions();
     closures();
+    modules();
 }

rust-examples/src/modules.rs

+///模块
+pub fn modules() {
+    struct_visibility();
+    cfg();
+}
+
+fn struct_visibility() {
+    mod my {
+        //公有结构体和公有字段
+        pub struct OpenBox<T> {
+            pub contents: T,
+        }
+
+        //公有结构体和私有字段
+        #[allow(dead_code)]//禁用编译器的 未使用警告
+        pub struct ClosedBox<T> {
+            contents: T,
+        }
+
+        impl<T> ClosedBox<T> {
+            //公有的构造函数
+            pub fn new(contents: T) -> ClosedBox<T> {
+                ClosedBox {
+                    contents: contents,
+                }
+            }
+        }
+    }
+
+    let open_box = my::OpenBox { contents: "public information" };
+    println!("The open box contains: {}", open_box.contents);
+
+    //ERROR
+    //let closed_box = my::ClosedBox { contents: "classified information" };
+
+    //使用构造函数可以
+    let _closed_box = my::ClosedBox::new("classified information");
+
+    //ERROR
+    //println!("The closed box contains: {}", _closed_box.contents);
+}
+
+fn use_declaration() {
+    //指定别名
+    // use deeply::nested::function as other_function;
+    // other_function();
+
+    //相对路径，父级和当前级
+    //super 和 self
+}
+
+//extern crate rary; 导入library库
+
+fn cfg() {
+    // This function only gets compiled if the target OS is linux
+    #[cfg(target_os = "linux")]
+    fn are_you_on_linux() {
+        println!("You are running linux!");
+    }
+
+    // And this function only gets compiled if the target OS is *not* linux
+    #[cfg(not(target_os = "linux"))]
+    fn are_you_on_linux() {
+        println!("You are *not* running linux!");
+    }
+
+    are_you_on_linux();
+
+    println!("Are you sure?");
+    if cfg!(target_os = "linux") {//target_os由rustc隐式提供，但是自定义条件条件必须使用--cfg标志传递给rustc
+        println!("Yes. It's definitely linux!");
+    } else {
+        println!("Yes. It's definitely *not* linux!");
+    }
+}
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