Skip to content

Latest commit

 

History

History
129 lines (85 loc) · 2.96 KB

pgn.rst

File metadata and controls

129 lines (85 loc) · 2.96 KB

PGN parsing and writing

Game model

Games are represented as a tree of moves. Each GameNode can have extra information such as comments. The root node of a game (Game extends GameNode) also holds general information, such as game headers.

.. autoclass:: chess.pgn.Game
    :members:

    .. py:attribute:: headers

        A `collections.OrderedDict()` of game headers.


.. autoclass:: chess.pgn.GameNode
    :members:

    .. py:attribute:: parent

        The parent node or `None` if this is the root node of the game.

    .. py:attribute:: move

        The move leading to this node or `None` if this is the root node of the
        game.

    .. py:attribute:: nags
        :annotation: = set()

        A set of NAGs as integers. NAGs always go behind a move, so the root
        node of the game can have none.

    .. py:attribute:: comment
        :annotation: = ''

        A comment that goes behind the move leading to this node. The root
        node of the game can have no comment.

    .. py:attribute:: starting_comment
        :annotation: = ''

        A comment for the start of a variation or the game. Only nodes that
        actually start a variation (`starts_variation()`) and the game itself
        can have a starting comment.

    .. py:attribute:: variations

        A list of child nodes.

Parsing

.. autofunction:: chess.pgn.read_game


.. autofunction:: chess.pgn.scan_offsets

Writing

If you want to export your game game with all headers, comments and variations you can use:

>>> print(game)
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
<BLANKLINE>
1. e4 e5 { Comment } *

Remember that games in files should be separated with extra blank lines.

>>> print(game, file=handle, end="\n\n")

Use exporter objects if you need more control. Exporter objects are used to allow extensible formatting of PGN like data.

.. autoclass:: chess.pgn.StringExporter
    :members:


.. autoclass:: chess.pgn.FileExporter
    :members:

NAGs

Numeric anotation glyphs describe moves and positions using standardized codes that are understood by many chess programs. During PGN parsing, annotations like !, ?, !!, etc. are also converted to NAGs.

.. py:data:: NAG_NULL
    :annotation: = 0


.. py:data:: NAG_GOOD_MOVE
    :annotation: = 1

    A good move. Can also be indicated by `!` in PGN notation.


.. py:data:: NAG_MISTAKE
    :annotation: = 2

    A mistake. Can also be indicated by `?` in PGN notation.


.. py:data:: NAG_BRILLIANT_MOVE
    :annotation: = 3

    A brilliant move. Can also be indicated by `!!` in PGN notation.


.. py:data:: NAG_BLUNDER
    :annotation: = 4

    A blunder. Can also be indicated by `??` in PGN notation.


.. py:data:: NAG_SPECULATIVE_MOVE
    :annotation: = 5

    A speculative move. Can also be indicated by `!?` in PGN notation.


.. py:data:: NAG_DUBIOUS_MOVE
    :annotation: = 6

    A dubious move. Can also be indicated by `?!` in PGN notation.