Zig Collections

NOTE Tested on the current stable version of Zig (0.13.0 as of today) and on the latest Mach Nominated Zig version

Implementation of some useful data structures in Zig. Inspired by Python's collections module.

Installation

1. In the root directory of your project, run the following command to add zig-collections to your build.zig.zon file:

   zig fetch --save https://github.com/insolor/zig-collections/archive/refs/heads/main.zip
   

   Replace main in the URL with the tag you want to use.

2. Add zig-collections as a dependency module in your build.zig file, example:

   const zig_collections = b.dependency("zig-collections", .{});
   exe.root_module.addImport("zig-collections", zig_collections.module("zig-collections"));
   

After that, you'll be able to import zig-collections namespace from your code:

const zig_collections = @import("zig-collections");
const Counter = zig_collections.Counter;
const DefaultHashMap = zig_collections.DefaultHashMap;

Usage examples

Implemented so far:

• ✅ Counter:
  • a minimal functionality is implemented: increment of a value of a key, counting of duplicate values from a slice or an iterator
• ✅ defaultdict (DefaultHashMap)

Counter usage examples:

test "test add from slice" {
    var counter = Counter(u8).init(allocator);
    defer counter.deinit();

    const array = [_]u8{ 1, 2, 2, 3, 3, 3 };
    try counter.addFromSlice(array[0..]);
    try expectEqual(1, counter.get(1));
    try expectEqual(2, counter.get(2));
    try expectEqual(3, counter.get(3));
}

test "test add from iterator" {
    var counter = Counter([]const u8).init(allocator);
    defer counter.deinit();

    const text = "alice bob alice";
    var iterator = std.mem.splitSequence(u8, text, " ");
    try counter.addFromIterator(&iterator);
    try expectEqual(2, counter.get("alice"));
    try expectEqual(1, counter.get("bob"));
}

DefaultHashMap example:

test "test defaulthashmap list" {
    const Factory = struct {
        allocator: std.mem.Allocator,

        fn produce(self: @This()) ArrayList(u8) {
            return ArrayList(u8).init(self.allocator);
        }
    };

    var map = collections.DefaultHashMap(
        u8,
        ArrayList(u8),
        Factory{ .allocator = allocator },
        Factory.produce,
    ).init(allocator);

    defer {
        map.deinitValues();
        map.deinit();
    }

    const array = [_]u8{ 3, 3, 1, 2, 3, 2 };
    for (array, 0..) |item, i| {
        map.get(item).append(@intCast(i)) catch unreachable;
    }

    try expectEqualDeep(&[_]u8{2}, map.get(1).items);
    try expectEqualDeep(&[_]u8{ 3, 5 }, map.get(2).items);
    try expectEqualDeep(&[_]u8{ 0, 1, 4 }, map.get(3).items);
}