README.md

tree-sitter-pgn

Overview

Chess Portable Game Notation (PGN) grammar for tree-sitter.

Used in

• Emacs pygn-mode

Highlighting Example

Python Example

import more_itertools
from tree_sitter import Language, Parser
import tree_sitter_pgn as ts_pgn

PGN_LANGUAGE = Language(ts_pgn.language())
parser = Parser(PGN_LANGUAGE)

query = PGN_LANGUAGE.query(
    '''
    (series_of_games
      game: (game) @game)

    (movetext
      san_move: (san_move) @san_move)

    (movetext
      lan_move: (lan_move) @lan_move)
    ''')

with open('input_file.pgn', 'rb') as file:
    tree = parser.parse(file.read())

matches = query.captures(tree.root_node)

merged_nodes = [
    *matches.get('game', []),
    *matches.get('san_move', []),
    *matches.get('lan_move', []),
]
merged_nodes = sorted(merged_nodes, key=lambda elt: elt.start_byte)

for game in more_itertools.split_before(merged_nodes, lambda node: node.type == 'game'):
    main_line = []
    for node in game:
        if node.type in ['san_move', 'lan_move'] and node.text is not None:
            main_line.append(node.text.decode().strip())
            continue
    print(' '.join(main_line))

References

• PGN specification
• Commonly-used extensions
• Commonly-used annotation glyphs