# Multi-bounded-array

**URL:** <https://ziggit.dev/t/multi-bounded-array/8388>\
**Category:** Showcase\
**Created:** [February 5, 2025, 10:42pm UTC](https://ziggit.dev/t/multi-bounded-array/8388 "2025-02-05T22:42:54Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Travis](https://ziggit.dev/letter_avatar_proxy/v4/letter/t/bbce88/32.png) [@Travis](https://ziggit.dev/u/Travis)\
**Post date:** [February 5, 2025, 10:42pm UTC](https://ziggit.dev/t/multi-bounded-array/8388/1 "2025-02-05T22:42:54Z")

</div>

[https://github.com/travisstaloch/multi-bounded-array](https://github.com/travisstaloch/multi-bounded-array)

# About

Similar to std.MultiArrayList() but backed by fixed size arrays with a  
shared runtime length.

Each field of T becomes an array with max length `buffer_capacity`. To  
access the arrays as slices use `items(field)` or `constItems(field)`.

Useful when a struct of small arrays is desired with capacity that is  
known at compile time. Like std.BoundedArray, MultiBoundedArrays are only  
values and thus may be copied.

# Usage

```console
$ zig fetch --save=multi-bounded-array git+https://github.com/travisstaloch/multi-bounded-array#main"

```

```zig
// build.zig
const dep = b.dependency("multi-bounded-array", .{ .optimize = optimize, .target = target });
exe.root_module.addImport("multi-bounded-array", dep.module("multi-bounded-array"));

```

```zig
// main.zig
const MultiBoundedArray = @import("multi-bounded-array").MultiBoundedArray;
var a = MultiBoundedArray(struct { int: u8, float: f32 }, 64){};
// ...

```

# Example

From tests in lib.zig which also contains more tests.

```zig
test "basic" {
    const T = struct { int: u8, float: f32 };
    var a = MultiBoundedArray(T, 64){};
    try testing.expectEqual(0, a.len);
    try a.append(.{ .int = 1, .float = 1 });
    const mut_ints = a.items(.int);
    // items() slice constness is inherited
    try testing.expectEqual([]u8, @TypeOf(mut_ints));
    try testing.expectEqual(1, mut_ints.len);
    try testing.expectEqual(1, mut_ints[0]);
    mut_ints[0] = 2;
    const a_const_copy = a;
    mut_ints[0] = 3;
    const const_ints = a_const_copy.items(.int);
    // items() slice constness is inherited
    try testing.expectEqual([]const u8, @TypeOf(const_ints));
    try testing.expectEqual(2, const_ints[0]);
}

```

---

<div class="post-metadata">

**Author:** ![Travis](https://ziggit.dev/letter_avatar_proxy/v4/letter/t/bbce88/32.png) [@Travis](https://ziggit.dev/u/Travis)\
**Post date:** [February 6, 2025, 11:03am UTC](https://ziggit.dev/t/multi-bounded-array/8388/2 "2025-02-06T11:03:08Z")

</div>

Update: I’ve added support tagged unions and sorting and also added all tests from std.MultiArrayList.