How to write a custom hash function ? | Zig Programming Language | Page 1

Hello guys, I have to write a custom hash function on a specific type with strings in its fields, Here it's the type LayoutElement, as you can see their is a nested structure so it makes things difficult...

// The type I want to store as key of HashMap :
pub const LayoutElement = struct {
    data: LayoutElementKind,
    media_query: ?MediaQuery,
};

pub const LayoutElementKind = union(enum) {
    component: Component,
    utility: LayoutClass,
};

pub const Component = union(enum) {
    box: Box,
    center: Center,
};

pub const Box = struct {
    max_width: []const u8 = "",
    grow: bool = false,
};

pub const Center = struct {
    max_width: []const u8 = "",
    and_text: bool = false,
    recursive: bool = false,
};

pub const LayoutClassName = enum(u32) {
    //Component Attributes
    max_width = 0,
    grow,
    and_text,
    recursive,
    // Utilities
    pb = 100,
};

pub const LayoutClass = struct {
    name: LayoutClassName,
    value: []const u8,
};

pub const MediaQuery = union(enum) {
    superior_to: struct { breakpoint: usize, value: []const u8 },
    inferior_or_equal_to: struct { breakpoint: usize },
};```

#How to write a custom hash function ?