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使用 try 传播失败

用一个关键字向上层传递错误。

使用 try 传播失败 是 CoddyKit 上的免费 Zig Academy 课时。这是第 3 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 Zig Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Zig Academy 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

Handling Gets Repetitive

Writing an if-else around every fallible call to forward its error gets noisy fast. Zig offers a shortcut: the try keyword.

try Unwraps or Returns

Put try before a fallible call. On success it hands you the value; on error it returns that error from your current function.

const n = try parse(input);

It Is Pure Sugar

That one line is exactly the same as catching the error and returning it yourself. try just writes the boilerplate for you.

const n = parse(input) catch |e| return e;

Your Function Must Be Fallible

Because try can return an error, the enclosing function needs an error union return type. Otherwise the compiler rejects it.

fn run() !void {
    const n = try parse(input);
}

Chain Many tries

Stack several try calls in a row. Each one stops the function early on failure, so the happy path reads top to bottom.

const f = try open(path);
const data = try read(f);

try in the Middle of Expressions

You can place try right inside a larger expression. The unwrapped value flows straight into the surrounding call or math.

const total = base + try parse(input);

try with void Calls

Even when a call returns !void, use try to forward any failure. You get no value back, only the early return on error.

try file.writeAll(data);

Errors Climb the Stack

With try in every layer, a failure deep down propagates all the way up until some caller finally decides to handle it.

Readable Happy Path

The big win is clarity: error forwarding fades into a single keyword, so the main logic stays front and center.

try Does Not Handle

Remember that try only forwards an error; it never recovers from one. To react locally you reach for catch instead.

When to Forward

Use try when the right move is to let the caller deal with failure. Most intermediate functions simply pass errors upward.

Quick Check

You write try doThing() inside a function. What happens if doThing returns an error?

Recap

You learned that try unwraps on success and returns the error otherwise. It is shorthand for catch and forward, keeping code clean. ✅

常见问题解答

「使用 try 传播失败」课时是免费的吗？

是的 — 「使用 try 传播失败」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Zig Academy 课程的其余内容，请升级到 CoddyKit PRO。 Zig Academy 课程共包含 4 节课。

「使用 try 传播失败」这节课中我会学到什么？

用一个关键字向上层传递错误。你通过在浏览器中直接运行的动手代码来练习 Zig Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

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无需任何先前经验。CoddyKit 上的 Zig Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 3 节课，共 4 节。

「使用 try 传播失败」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 Zig Academy 课中编写并运行代码吗？

能。每节 Zig Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

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