vagrawal/thc-chess-library

General Purpose Rules of Chess Library for C++

This repository serves as the genesis of the files src/thc.cpp and src/thc.h in the peer repository tarrasch-chess-gui. Those files serve as a bedrock chess API for the program Tarrasch Chess GUI. Those two files are basically a concatenation of the files present in this library. The idea for that was inspired by SQLite, which is similarly distributed as single concatenated .c and .h files to avoid the pain point of integrating a library into a project.

This repository has recently been brought up to date with its peer tarrasch-chess-gui repository. It is easier to understand the more granular presentation of the code in this repository. I used to say One day it would be nice to add a python script or similar to this repository to automatically regenerate the concatenated two file version of the library. I can now (August 7th 2019) say that this has been successfully implemented with a new program test-framework.cpp. This should make it practical to keep the repositories in sync from now on.

Background

This is a general purpose chess library for C++. It provides clients with simple facilities for creating and manipulating chess positions and moves in accordance with the rules of standard chess.

Features

• Import/export positions using FEN (Forsyth Edwards Notation)
• Import/export moves using SAN (Standard algebraic notation)
• Generate legal move list, understands all chess rules
• Make moves in positions, push and pop moves in positions
• Evaluate positions for mate and all draw rules
• Compress positions
• Generate fast position hash codes move by move.
• Fast operation using lookup tables, efficient data structures

Status

This code was written as part of the Tarrasch Chess GUI [see peer repository/(ies)]. At a certain point it seemed sensible to break the Chess API out into a library. After some experience with using a thc.lib / thc.a static library with Visual Studio/Windows and XCode/Mac I have reluctantly concluded that libraries can be very annoying and I now use a slightly different mechanism; I concatenate the modules together and provide a single thc.cpp and thc.h file to include in any project in the simplest possible way. This idea was inspired by SQLite3 which does the same thing. The thc.cpp and thc.h files are in the source directory, and they are the only files you need EXCEPT, unfortunately DebugPrintf.h and Portability.h, which are Tarrasch Chess GUI files and are also needed just at the moment. The presence of DebugPrintf.h requires that the user contribute a DebugPrintfInner() or similar function.

CMake Build

If you instead use CMake as a build system, you may prefer adding the library to your project as a CMake submodule. CMakeLists.txt provides the variable THC_CHESS_INCLUDE for the headers include directory and the libraries thc_chess (shared) and thc_chess_static (static).

Usage example:

add_subdirectory("${PROJECT_SOURCE_DIR}/path/to/library" EXCLUDE_FROM_ALL)
include_directories(${THC_CHESS_INCLUDE})
target_link_libraries(your_binary_name thc_chess_static) # or thc_chess for dynamic linking

To Do

I would like to do a bit of a renaming exercise - I am moving away from "using" and prefer explicit use of namespaces. All the thc library code is in namespace thc, so thc::position for example would be more logical than thc::ChessPosition (note thc = triple happy chess, where triple happy comes from triplehappy.com, a domain I use).

An annoying thing is that all the code in this repository seems to have reverted to Windows CR/LF endings despite me carefully standardising on LF only. I need to sort this out. I blame (possibly unfairly) GitHub.

Although you won't find much test code (yet), the code is battle proven from years of use and incremental improvement inside the Tarrasch Chess GUI project.

Bill Forster [email protected] 25Mar2014