PgnToFen

A utility for transforming a PGN file of chess games into a list of all the positions in those games. The application is written in C# in .NET Core.

The project makes heavy use of a couple of other projects:

• ilf.pgn.net - for parsing PGN files into chess game data. That project is a .NET Core port of this project.

• Chess.NET - for converting positions into FENs.

Simple Example

Input:

[White "P1"]
[Black "P2"]
[Result "1-0"]

1. e4 e5 2. Bc4 Nc6 3. Qh5 Nf6 4. Qxf7# 1-0

Output:

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1
rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2
rnbqkbnr/pppp1ppp/8/4p3/2B1P3/8/PPPP1PPP/RNBQK1NR b KQkq - 1 2
r1bqkbnr/pppp1ppp/2n5/4p3/2B1P3/8/PPPP1PPP/RNBQK1NR w KQkq - 2 3
r1bqkbnr/pppp1ppp/2n5/4p2Q/2B1P3/8/PPPP1PPP/RNB1K1NR b KQkq - 3 3
r1bqkb1r/pppp1ppp/2n2n2/4p2Q/2B1P3/8/PPPP1PPP/RNB1K1NR w KQkq - 4 4
r1bqkb1r/pppp1Qpp/2n2n2/4p3/2B1P3/8/PPPP1PPP/RNB1K1NR b KQkq - 0 4

How to use

You can run the application from the command line with the name of the file to convert. For example:

PgnToFen.exe --pgnfile MyPgnFile.pgn

This will create a file called MyPgnFile.txt containing a list of all of the FENs, in the same directory as the PGN file.

You can optionally specify the location to output the FENs to with the --output flag:

PgnToFen.exe --pgnfile MyPgnFile.pgn --output MyFenFile.txt

You can also use it as part of your own project. Once you've imported PgnToFen into your solution, you can use the snippet below to save FENs to a specific location:

var conversionStrategy = new SaveFensToFileStrategy("MyFenFile.txt");
PgnToFenConverter.Convert(conversionStrategy, "MyPgnFile.pgn");

There are a couple of other 'strategies' you can use to do different things with the FENs. For example, this snippet will put all FENs into a List<string>:

var conversionStrategy = new SaveFensToListStrategy();
PgnToFenConverter.Convert(conversionStrategy, "MyPgnFile.pgn");

foreach (var fen in conversionStrategy.Fens)
    Console.WriteLine(fen);

There is also an AdvancedSaveFensToListStrategy, which is similar to the above, but instead of storing just the FEN, it will also store some metadata, such as who won the game in the end.

var conversionStrategy = new AdvancedSaveFensToListStrategy();
PgnToFenConverter.Convert(conversionStrategy, "MyPgnFile.pgn");

var decisivePositions = conversionStrategy.Positions
    .Where(position => position.FinalResult != FinalGameResult.Draw);

foreach (var position in decisivePositions)
    Console.WriteLine(position.Fen);