spacebat

Sometimes I'd like to read from a stream that under the hood calls a supplied function to produce the next element, or write to a stream that rather than writing to disk or building a string, calls a supplied function with the character(s) written.

I've searched for this in the past and just now, best I've come up with is writing my own gray stream subclass. Is that in fact the best option? I use SBCL and LW, but the more portable the better.

Keybase proof

I hereby claim:

• I am spacebat on reddit.
• I am spacebat on keybase.
• I have a public key whose fingerprint is 0929 8712 0340 D898 4381 69DD 3067 D9AD 2796 55F6

To claim this, I am signing this object:

{
    "body": {
        "key": {
            "fingerprint": "092987120340d898438169dd3067d9ad279655f6",
            "host": "keybase.io",
            "key_id": "3067d9ad279655f6",
            "kid": "01015e6ca46c25b830e8c4e76242cf48015f73fdd22c7819e077a7c72a3c9cc4a4c90a",
            "uid": "1d5db5160bc80d7dbbcf186fa97d4400",
            "username": "space