// io — stream interface (Plan 9 Bio / Hare io::stream shape).
//
// No closures, no methods. A `stream` is a struct of function
// pointers plus a `ctx: *void`. The error channel is the return
// value of read/write/close — Hare-shaped tagged unions instead of
// errno-style integer sentinels.

// eof — read past the end of the stream. NAMED-void so it's a
// distinct variant tag from `void` (which would be "no result yet").
export type eof = void;

// closed — operation attempted on a stream that has already been
// closed. NAMED-void; same shape, different tag.
export type closed = void;

export type stream = struct {
	ctx:    *void,
	read:   fn(s: *stream, buf: []u8) (i32 | eof | closed),
	write:  fn(s: *stream, buf: []u8) (i32 | closed),
	close:  fn(s: *stream) (void | closed),
};

export fn read(s: *stream, buf: []u8) (i32 | eof | closed) = {
	return s.read(s, buf);
};

export fn write(s: *stream, buf: []u8) (i32 | closed) = {
	return s.write(s, buf);
};

export fn close(s: *stream) (void | closed) = {
	return s.close(s);
};