2 ms·

Why was this downvoted? Is it not factual? If it's not, it would be far more helpful if it would be pointed out. If it's implemented as stated by int_19h then

• int_19h 8y ago
  The protocol itself is transport-agnostic - it just needs a bidirectional stream, and the spec doesn't define what it is. In practice, both stdin/stdout and sockets are used - the latter usually for language servers that are "heavyweight", such that it is advantageous to spin up the server once, "prime" it (let it do any indexing etc), and then reuse it between concurrent sessions. The standard streams are usually the default choice for simplicity reasons, though. Implementing a server in Brainfuck is theoretically possible, but only if you ignore the heat death of the universe as the upper time boundary. ~