update: update gpa to DebugAllocator in learn module#119
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This pull request updates the Zig tutorial documentation to replace the deprecated GeneralPurposeAllocator with the new DebugAllocator for Zig 0.16.0. However, the reviewer identified a widespread syntax error: std.heap.DebugAllocator is a struct rather than a generic function, meaning that initializing it with (.{}){} will result in a compilation error; it should be initialized directly as std.heap.DebugAllocator{}. Additionally, several explanations and Chinese translations in the documentation still incorrectly describe it as a generic function or refer to it as the "General Purpose Allocator" and need to be corrected.
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| var dpa = std.heap.DebugAllocator(.{}){}; | ||
| const allocator = dpa.allocator(); |
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| var dpa = std.heap.DebugAllocator(.{}){}; | ||
| const allocator = dpa.allocator(); |
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| var dpa = std.heap.DebugAllocator(.{}){}; | ||
| const allocator = dpa.allocator(); |
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| var dpa = std.heap.DebugAllocator(.{}){}; | ||
| const allocator = dpa.allocator(); |
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| var dpa = std.heap.DebugAllocator(.{}){}; | ||
| const allocator = dpa.allocator(); |
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| 你可能会注意到,创建 `dpa` 的语法有点奇怪。什么是`DebugAllocator(.{}){}`? | ||
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| 我们之前见过这些东西,只是现在都混合了起来。`std.heap.GeneralPurposeAllocator` 是一个函数,由于它使用的是 `PascalCase`(帕斯卡命名法),我们知道它返回一个类型。(下一部分会更多讨论泛型)。也许这个更明确的版本会更容易解读: | ||
| 我们之前见过这些东西,只是现在都混合了起来。`std.heap.DebugAllocator` 是一个函数,由于它使用的是 `PascalCase`(帕斯卡命名法),我们知道它返回一个类型。(下一部分会更多讨论泛型)。也许这个更明确的版本会更容易解读: | ||
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| ```zig | ||
| const T = std.heap.GeneralPurposeAllocator(.{}); | ||
| var gpa = T{}; | ||
| const T = std.heap.DebugAllocator(.{}); | ||
| var dpa = T{}; | ||
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| // 等同于: | ||
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| var gpa = std.heap.GeneralPurposeAllocator(.{}){}; | ||
| var dpa = std.heap.DebugAllocator(.{}){}; | ||
| ``` |
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Since std.heap.DebugAllocator is a struct and not a generic function, the explanation about DebugAllocator(.{}){} being a function that returns a type is incorrect and misleading. We should update this section to explain that it is a simple struct initialized with {}.
Note that since DebugAllocator is a simple struct and does not use std.heap.general_purpose_allocator.Config, the subsequent paragraph (around line 302 in the original file) explaining Config and default values is also obsolete and should be removed or updated in a separate change.
Suggested replacement:
创建 dpa 的语法非常简单:std.heap.DebugAllocator{}。因为 DebugAllocator 是一个结构体(struct),而不是像以前的 GeneralPurposeAllocator 那样是一个返回类型的泛型函数,所以我们不需要传递配置参数,直接实例化即可:
var dpa = std.heap.DebugAllocator{};| ## [std.testing.allocator]($heading.id('std-testing-allocator')) | ||
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| 希望当我们谈到内存泄漏时,你已经足够烦恼,而当我提到 Zig 可以提供帮助时,你肯定渴望了解更多这方面内容。这种帮助来自 `std.testing.allocator`,它是一个 `std.mem.Allocator` 实现。目前,它基于通用分配器(GeneralPurposeAllocator)实现,并与 Zig 的测试运行器进行了集成,但这只是实现细节。重要的是,如果我们在测试中使用 `std.testing.allocator`,就能捕捉到大部分内存泄漏。 | ||
| 希望当我们谈到内存泄漏时,你已经足够烦恼,而当我提到 Zig 可以提供帮助时,你肯定渴望了解更多这方面内容。这种帮助来自 `std.testing.allocator`,它是一个 `std.mem.Allocator` 实现。目前,它基于通用分配器(DebugAllocator)实现,并与 Zig 的测试运行器进行了集成,但这只是实现细节。重要的是,如果我们在测试中使用 `std.testing.allocator`,就能捕捉到大部分内存泄漏。 |
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The Chinese text still refers to DebugAllocator as "通用分配器" (General Purpose Allocator). It should be updated to "调试分配器" (Debug Allocator) to match the new allocator name.
Suggested replacement:
希望当我们谈到内存泄漏时,你已经足够烦恼,而当我提到 Zig 可以提供帮助时,你肯定渴望了解更多这方面内容。这种帮助来自 std.testing.allocator,它是一个 std.mem.Allocator 实现。目前,它基于调试分配器(DebugAllocator)实现,并与 Zig 的测试运行器进行了集成,但这只是实现细节。重要的是,如果我们在测试中使用 std.testing.allocator,就能捕捉到大部分内存泄漏。
| var dpa = std.heap.DebugAllocator(.{}){}; | ||
| const allocator = dpa.allocator(); |
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| var dpa = std.heap.DebugAllocator(.{}){}; | ||
| const allocator = dpa.allocator(); |
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| var dpa = std.heap.DebugAllocator(.{}){}; | ||
| const allocator = dpa.allocator(); |
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Pull request overview
This PR updates the learn-module documentation examples to stop using std.heap.GeneralPurposeAllocator and instead demonstrate std.heap.DebugAllocator, aligning the tutorial with newer Zig standard library allocator naming/usage.
Changes:
- Replaced
GeneralPurposeAllocatorusages in code snippets withDebugAllocator(gpa→dpa) across learn articles. - Updated headings and explanatory text in the heap-memory lesson to describe
DebugAllocator. - Adjusted allocator-related examples and surrounding narrative to match the new allocator choice.
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.
| File | Description |
|---|---|
| content/learn/heap-memory.smd | Updates allocator section (heading, narrative, and multiple code snippets) to use DebugAllocator instead of GeneralPurposeAllocator. |
| content/learn/generics.smd | Updates the allocator instantiation in the generics example to use DebugAllocator. |
| content/learn/coding-in-zig.smd | Updates multiple code examples to use DebugAllocator in place of GeneralPurposeAllocator. |
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| const T = std.heap.DebugAllocator(.{}); | ||
| var dpa = T{}; | ||
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| // 等同于: | ||
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请按照英文原文进行适配,那边已经适配0.16了 |
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Fixed, please review again. |
| fn classify(power_level: u32) ![]const u8 { | ||
| var buf: [20]u8 = undefined; | ||
| return std.fmt.bufPrint(&buf, "over: {d}\n", .{power_level}); | ||
| } |
| var buf: [20]u8 = undefined; | ||
| const msg = try std.fmt.bufPrint(&buf, "over: {d}!\n", .{power_level}); | ||
| std.debug.print("{s}\n" , .{msg}); |
| ``` | ||
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| 上述代码仍然创建了一个 16 字节的数组,但它的每个元素都没有被赋值。 | ||
| 上述代码仍然创建了一个 20 字节的数组,但它的每个元素都没有被赋值。 |
| ```zig | ||
| pub fn main() void { | ||
| std.debug.print("{any}\n", .{@TypeOf(.{.year = 2023, .month = 8})}); | ||
| std.debug.print("{}\n", .{.{.year = 2023, .month = 8}}); |
| // TODO: use a proper seed, not 0. | ||
| var prng = std.Random.DefaultPrng.init(0); | ||
| const random = prng.random(); | ||
| return random.uintAtMost(u8, 5) + 5; |
| ## [std.testing.allocator]($heading.id('std-testing-allocator')) | ||
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| 希望当我们谈到内存泄漏时,你已经足够烦恼,而当我提到 Zig 可以提供帮助时,你肯定渴望了解更多这方面内容。这种帮助来自 `std.testing.allocator`,它是一个 `std.mem.Allocator` 实现。目前,它基于通用分配器(GeneralPurposeAllocator)实现,并与 Zig 的测试运行器进行了集成,但这只是实现细节。重要的是,如果我们在测试中使用 `std.testing.allocator`,就能捕捉到大部分内存泄漏。 | ||
| 希望当我们谈到内存泄漏时,你已经足够烦恼,而当我提到 Zig 可以提供帮助时,你肯定渴望了解更多这方面内容。这种帮助来自 `std.testing.allocator`,它是一个 `std.mem.Allocator` 实现。目前,它基于通用分配器(DebugAllocator)实现,并与 Zig 的测试运行器进行了集成,但这只是实现细节。重要的是,如果我们在测试中使用 `std.testing.allocator`,就能捕捉到大部分内存泄漏。 |
| const builtin = @import("builtin"); | ||
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| pub fn main() !void { | ||
| var gpa: std.heap.DebugAllocator(.{}) = .empty; |
| ``` | ||
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| 值看起来没问题,但键不一样。如果你不确定发生了什么,那可能是我的错。之前,我故意误导了你的注意力。我说哈希表通常声明周期会比较长,因此需要同等生命周期的值(value)。事实上,哈希表不仅需要长生命周期的值,还需要长生命周期的键(key)!请注意,`buf` 是在 `while` 循环中定义的。当我们调用 `put` 时,我们给了哈希表插入一个键值对,这个键的生命周期比哈希表本身短得多。将 `buf` 移到 `while` 循环之外可以解决生命周期问题,但每次迭代都会重复使用缓冲区。由于我们正在更改底层的键数据,因此它仍然无法工作。 | ||
| 值看起来没问题,但键不一样。如果你不确定发生了什么,那可能是我的错。之前,我故意误导了你的注意力。我说哈希表通常生命周期会比较长,因此需要同等生命周期的值(value)。事实上,哈希表不仅需要长生命周期的值,还需要长生命周期的键(key)!请注意,`buf` 是在 `while` 循环中定义的。当我们调用 `put` 时,我们给了哈希表插入一个键值对,这个键的生命周期比哈希表本身短得多。将 `buf` 移到 `while` 循环之外可以解决生命周期问题,但每次迭代都会重复使用缓冲区。由于我们正在更改底层的键数据,因此它仍然无法工作。 |
| 但是如果我们传递一个实现了`writeAll`函数的`*std.Io.Writer`对象,代码就能正常运行 | ||
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| ```bash | ||
| User 1 has power of 10 | ||
| User 2 has power of 20 | ||
| over 9000\n |
Remove
std.heap.GeneralPurposeAllocator,update tostd.heap.DebugAllocatorin learn module.