Clayfish is a toy chess engine written in C using Pottery containers and algorithms.

It has a simple command-line interface for playing chess. It also supports the UCI protocol so it can be used with chess GUIs and chess AI tournament software like Cute Chess. Pass -u as a command-line argument to run it in UCI mode.

Clayfish demonstrates various uses of Pottery in a "real" application:

• A Pottery vector of moves is used for move generation, principal variation storage, etc. It uses a large internal capacity to almost always avoid allocations, although it can grow to arbitrary size. This demonstrates how to instantiate a non-static container with a custom .t.h file to avoid duplicating the configuration. See move.h and moves.t.h for the vector configuration.

• Pottery's quick sort is used to sort move lists to improve alpha-beta search. It demonstrates how to use a comparison expression with an external context (the game board.) See it in search.c.

• Pottery's string is used extensively in UCI protocol parsing and general string formatting. Take a look at position_format() to see how nice this is compared to standard C strings.

• A Pottery ring of Pottery strings is used to queue input from a background thread that blocks on standard input. This demonstrates how to store a non-bitwise-movable type in a Pottery container. See it in uci.c.