zig/test/cases/this.zig

const assert = @import("std").debug.assert;

const module = this;

fn Point(comptime T: type) type {
    return struct {
        const Self = this;
        x: T,
        y: T,

        fn addOne(self: *Self) void {
            self.x += 1;
            self.y += 1;
        }
    };
}

fn add(x: i32, y: i32) i32 {
    return x + y;
}

fn factorial(x: i32) i32 {
    const selfFn = this;
    return if (x == 0) 1 else x * selfFn(x - 1);
}

test "this refer to module call private fn" {
    assert(module.add(1, 2) == 3);
}

test "this refer to container" {
    var pt = Point(i32){
        .x = 12,
        .y = 34,
    };
    pt.addOne();
    assert(pt.x == 13);
    assert(pt.y == 35);
}

test "this refer to fn" {
    assert(factorial(5) == 120);
}