PGN and Error Handling

Portable Game Notation (PGN)

The engine can import and export games in PGN format.

Header Tags

Standard tags include:

• Event: Name of the tournament or match.
• Site: Location.
• Date: When the game was played.
• Round: Round number.
• White/Black (or Red/Blue/Yellow/Green for 4-player).
• Result: Game outcome.

Error Handling

The parser is resilient to malformed PGNs but will throw descriptive errors for critical issues.

Error Code	Meaning
INVALID_MOVE	The SAN move cannot be parsed or applied to the current state.
STRICT_VIOLATION	Malformed tags or syntax in strict mode.
CAPACITY_EXCEEDED	The move list exceeds internal memory limits (rare).

Board Validation

Before applying an imported FEN or PGN, the engine performs a “deep check” to ensure:

• Exactly one King per active player.
• No pawns on the first or last rank (relative to color).
• Active player is not in a check they cannot escape (immediate stalemate/mate).