rust/demo/demo_std.rs · 5649 字节 · 下载原文

// demo_std.rs —— **标准输出**示范（Rust）

// demo_std.rs -- the **standard output** demo (Rust)

//

// 四层示范的第一层：只用这门语言自己的标准输出，**不读输入、不画图、不弹窗**，

// The first of the four demo layers: use only this language's own standard output, **no reading input, no drawing, no dialogs**,

// 输出**逐字节确定**（同样的二进制跑多少次都一样），能正常结束。

// the output is **byte-for-byte deterministic** (the same binary gives the same bytes on every run), and it exits normally.

//

// ◆ 判据

// ◆ The criterion

//

// 输出是确定的，所以这一份可以直接和期望文本逐字节比 —— 同目录另三份

// The output is deterministic, so this one can be compared byte-for-byte against the expected text -- the other three in this directory

// （`demo_tty` / `demo_bgi` / `demo_ui`）的判据都只能弱一档（编译零错误 +

// (`demo_tty` / `demo_bgi` / `demo_ui`) can only use a criterion one notch weaker (zero compile errors +

// 退出码 0 + 不挂死 / 出图不是全黑）。

// exit code 0 + no hang / the produced image is not all black).

//

// ◆ 写法（Rust 前端的两条实测约束）

// ◆ Style (two measured constraints of the Rust frontend)

//

//   · `println!` 的**第一个实参必须是字符串字面量**，格式化值走 `{}` 占位

//   · The **first argument of `println!` must be a string literal**; formatted values go through `{}` placeholders

//     （写 `println!(x)` 会打出 `[错误: println! 的第一个实参必须是字符串字面量]`）。

//     (writing `println!(x)` prints `[error: the first argument of println! must be a string literal]`).

//   · `\x1b` 这类转义**在本前端不解析**（会原样打出 `x1b` 四个字符）⇒ 要发控制字符

//   · Escapes like `\x1b` are **not parsed by this frontend** (it prints the four characters `x1b` verbatim) => to emit a control character

//     得走 `putchar(码)`（见 `demo_tty.rs`）。

//     go through `putchar(code)` (see `demo_tty.rs`).

//

// 跑法：命令行页输入  vml run examples/rust/demo_std.rs

// How to run: type this into the command-line page:  vml run examples/rust/demo_std.rs


// ◆ UI 库的显式引用

//   The explicit reference to the UI library

//

// `use vml_ui::*;` —— 声明文件是 `Lib/rust/vml_ui.rs`（GenLib 生成，155 个 `ui_*`，**不要手改**）：

// `use vml_ui::*;` -- the declaration file is `Lib/rust/vml_ui.rs` (generated by GenLib, 155 `ui_*`; **do not hand-edit**):

//

//     cd third_party/vml && dotnet run --project tools/GenLib -- -n -c vmlui -l rust -o Lib/rust/vml_ui.rs

//

// 本前端**不需要**声明就能解析 `ui_*`（它按 `ui_` 前缀自动链 `vmlui.vml`），

// This frontend resolves `ui_*` **without** any declaration (it auto-links `vmlui.vml` by the `ui_` prefix),

// 这条引用是**文档级**的：它标明"这个程序用 UI 库"，并让这份例程与其余语言同形。

// so this line is **documentation-level**: it states that this program uses the UI library and keeps

// this example shaped like every other language's.

// 实测（删掉这一行，产物与画面完全一致）：见仓库 docs 里那份「UI 库导入约定」的第二节 rust 行。

// Measured: deleting this line changes nothing -- the same instruction count and the same drawn picture;

// see the rust row in section two of the UI-library import convention document under docs.

#include "../../../Lib/rust/vml_ui.rs"
use vml_ui::*;

fn main() {
    let lang = ui_scr_get_language();

    println!("=== Dolaima demo_std (Rust) ===");

    // ① 字符串

    // ① String

    if lang == 0 { println!("[字符串] hello, world"); } else { println!("[string] hello, world"); }

    // ② 整数

    // ② Integer

    let n = 42;
    if lang == 0 { println!("[整数] n = {}", n); } else { println!("[int] n = {}", n); }

    // ③ 计算结果（字面量与变量都要能算）

    // ③ Computed results (both literals and variables must work)

    if lang == 0 { println!("[计算] 6 * 7 = {}", 6 * 7); } else { println!("[calc] 6 * 7 = {}", 6 * 7); }
    let a = 7;
    let b = 5;
    if lang == 0 { println!("[计算] a + b = {}", a + b); } else { println!("[calc] a + b = {}", a + b); }
    if lang == 0 { println!("[计算] a * b - 3 = {}", a * b - 3); } else { println!("[calc] a * b - 3 = {}", a * b - 3); }

    // ④ 循环里算斐波那契前 10 项（确定性）

    // ④ Compute the first 10 Fibonacci numbers in a loop (deterministic)

    if lang == 0 { println!("[循环] 斐波那契前 10 项："); } else { println!("[loop] first 10 Fibonacci numbers:"); }
    let mut x = 0;
    let mut y = 1;
    let mut i = 0;
    while i < 10 {
        let z = x + y;
        x = y;
        y = z;
        println!("  fib = {}", x);
        i = i + 1;
    }

    // ⑤ 累加：1+2+…+100

    // ⑤ Accumulation: 1+2+...+100

    let mut sum = 0;
    let mut k = 1;
    while k <= 100 {
        sum = sum + k;
        k = k + 1;
    }
    if lang == 0 { println!("[累加] 1+2+...+100 = {}", sum); } else { println!("[sum] 1+2+...+100 = {}", sum); }

    // ⑥ 阶乘

    // ⑥ Factorial

    let mut fact = 1;
    let mut m = 1;
    while m <= 5 {
        fact = fact * m;
        m = m + 1;
    }
    if lang == 0 { println!("[阶乘] 5! = {}", fact); } else { println!("[factorial] 5! = {}", fact); }

    if lang == 0 { println!("=== 结束 ==="); } else { println!("=== done ==="); }
}