This feels like it should've been a git issue rather than a blog post.

No feedback from the author, no explaining what the code does at a level for people new to zig, no explanations of the fundamental problem (i.e. files, buffers, and flow of data, and how to write that as code) and how it relates to what zig is doing, no alternate solution for how zig or other languages might try to solve the problem.

I have a strong suspicion that people are upvoting this based on the title of 'Zig' and 'unsafe' instead of the actual substance of the post.

I've never worked with Zig in my life, and I don't have an opinion on it either. I've heard it's neat. Despite that, this post was intuitively clear to me.

Zig's *std.Io.Reader and Writer seem to be abstractions over many types, like Java's interface class, Go's interfaces, C++'s concepts or Rust's traits. However, it seems that abstraction itself is leaky - in that the length of the buffer is an implicit dependency which cannot be known from the type alone.

Admittedly, we don't know if there's a good explanation for the behavior - but then again, HN comments are as good a place to learn as any. Maybe someone will come up and explain.

This is very readable if you know the language, plus a modicum of file I/O.