Crisp is a cryptocurrency written in Lisp. As of this writing, it's a toy blockchain written in Chez Scheme.
- Make Crisp a robust blockchain implementation written in Lisp that also uses Lisp as the transaction language.
- Experiment with the transaction language such that it provides features unavailable in existing blockchains
Crisp listens on a TCP port for control commands. Commands can be sent pretty naturally with telnet as commands are framed by the delimiter \r\n:
> blocks
> [{"index":0,"prev-hash":"","timestamp":1465154705,"data":"Genisis Block."}]
A command name and its arguments are delimited with spaces:
> peer-add 127.0.0.1 9998
> OK
| command | returns |
|---|---|
| blocks | json array of blocks |
| block-mine [msg] | newly mined block as json |
| block-last | the last block mined |
| peers | json array of peers as ip:port |
| peer-add ip port | OK |
| echo msg | msg |
Crisp peers gossip over TCP. Messages are encoded as ascii-length-prefixed JSON, where the message length and the messages themselves are delimited with \r\n. The JSON messages contain both a type and data field. When a peer asks another peer for its last block, the message looks like the following:
"31\r\n{\"type\":\"last-block\",\"data\":\"\"}\r\n"
| type | data |
|---|---|
| last-block | no data expected |
| last-block-resp | json encoded block |
| blocks | no data expected |
| blocks-resp | json array of blocks |
The valid chain with the most cumulative work always wins. Because we don't yet have transactions, valid here only means the chain itself is a valid blockchain. That is, the blocks are "linked" with the correct hash "pointers," and the timestamps between blocks is reasonable.
For the time being Crisp uses ravensc.com for package control and uses suv for io which you'll have to clone and build manually. The full process from scratch, assuming you already have chez and aren't on Windows:
$ curl -L http://ravensc.com/install | scheme
$ git clone git@github.com:huumn/crisp.git
$ cd crisp
$ raven install
$ cd lib
$ git clone git@github.com:huumn/suv.git
$ cd suv
$ cc -o3 -fPIC -shared c/suv.c -luv -o libsuv.so
$ cd ../..
$ scheme --script main.sc
You should then be able to connect to your Crisp node via telnet:
$ telnet 127.0.0.1 7777
echo hello
hello
blocks
[{"index":0,"prev-hash":"","timestamp":1465154705,"data":"Genisis Block."}]