Zig Writer Example

zig_writer_example.zig

pub const Foo: type = struct {
    alloc: std.mem.Allocator,
    buff: std.ArrayListUnmanaged(u8),

    pub fn init(alloc: std.mem.Allocator) Foo {
        return Foo{
            .alloc = alloc,
            .buff = std.ArrayListUnmanaged(u8){},
        };
    }

    pub const Writer = std.io.GenericWriter(*Foo, Foo.Error, Foo.writeFn);

    pub fn writer(self: *Foo) Writer {
        return Foo.Writer{ .context = self };
    }

    pub fn writeFn(self: *Foo, b: []const u8) Foo.Error!usize {
        try self.buff.appendSlice(self.alloc, b);

        return b.len;
    }

    pub const Error: type = error{
        OutOfMemory,
    };
};