Support PGN notation

[lrozenblyum]

It's a world standard and will simplify import/export of games

http://portablegamenotation.com/Specification.html - down at the moment of checking on 2020-12-20
https://www.thechessdrum.net/PGN_Reference.txt
http://www.saremba.de/chessgml/standards/pgn/pgn-complete.htm

• Acceptance criteria

  • Normal moves
    • Prevent ambiguous moves like in 1. d4 d5 2. Nf3 Nf6 3. Nd2 the 3'd
    • promotion
    • castling
    • captures
  • special moves
  • output ('export') mode only? (is 'import' to be split?)
    • reduced export format?
    • seven tag roster
    • For PGN export format, a single blank line appears after the last of the tag
      pairs to conclude the tag pair section. This helps simple scanning programs to
      quickly determine the end of the tag pair section and the beginning of the
      movetext section.
  • service fields
  • non-standard fields
  • game outcome
  • tool for validation might be useful: https://www.cs.kent.ac.uk/people/staff/djb/pgn-extract/help.html#flag-summary

• Issue with PGN itself https://zuttobenkyou.wordpress.com/2012/01/27/problems-with-the-portable-game-notation-pgn-standard/

  • Pay attention to encoding...
  • Line separators
  • 4.2. Tab character prohibition
  • Event (the name of the tournament or match event)
    • Simple case
    • Customization
    • colons processing (?)
    • special characers (?)
  • Site (the location of the event)
    • simple case
    • customization
  • Date (the starting date of the game)
    • known date
    • missing parts (?)
    • missing full day
  • Round (the playing round ordinal of the game)
    • number of game played
    • question if unknown
    • hyphen if not appropriate
  • White (the player of the white pieces)
    • human
      • Last name
      • first name/first initial
      • 1/more middle initials
      • More than 1 person playing white pieces
    • computer program
      • name
      • version information
    • Question mark if unknown
  • Black (the player of the black pieces)
  • Result (the result of the game)
    • white wins
    • black wins
    • drawn game
    • game still in progress
    • game abandoned
    • result otherwise unknown
    • same as termination marker in movetext
  • movetext section
    • export format (?): justification + 80
    • export format: space at start/end prohibition
    • The movetext section is composed of chess moves, move number indications,
      optional annotations, and a single concluding game termination marker.
    • move number indication
    • SAN
    • illegal moves not permitted
      • illegal moves permitted in commentary section
    • 8.2: Movetext section

• Architectural challenge

  • Where to implement: custom player? Game level?

• Testing ways

  • Engine vs Engine
  • Engine vs Winboard
    • Compare with Winboard-generated?
  • Engine vs UCI (?)
  • Import the output to some chess software, check if it's reasonable
  • extract a new project with PGN support (?)
  • PGNGameRealPlayersTest is running too long