chess/algebraic_notation

This module provides functionality to generate Standard Algrebaic Notation for chess moves.

Here are some examples of SAN:

e4 “Pawn to E4”

Qxd7 “Queen takes D7”

exd3+ “E-Pawn takes D3, check”

Nac3 “Knight A2 to C3”

Formatting rules

The formatting is generated as follows:

(<standard-move> | 'O-O' | 'O-O-O')<checks>

where:

• 'O-O' refers to a short castle
• 'O-O-O' refers to a long castle
• <checks> is:
  • '#' if this move checkmates the enemy king
  • '+' if this move checks the enemy king
  • otherwise empty

<standard-move> is defined as:

<figure><disambiguation><takes><destination><promotion>

where: (cases are processed from top to bottom)

• <figure> is:
  • empty for pawn
  • 'N' for knight
  • 'B' for bishop
  • 'R' for rook
  • 'Q' for queen
  • 'K' for king
• <disambiguation> is:
  • <file> if the moved figure is a pawn and it captures an enemy figure
  • empty if moved figure is unambigous
  • <file> if moved figure is ambigous and the ambigous figures are on different files
  • <row> if moved figure is ambigous and the ambigous figures are on different rows
  • <square> otherwise
• <takes> is:
  • 'x' if a capture takes place
  • empty otherwise
• <destination> is the <square> the figure is moved to
• <promotion> is:
  • '='<figure> if a pawn is promoting to <figure>
  • empty otherwise

pub type DescribeError {
  GameAlreadyOver
  ProvidedMoveIsIllegal
}

pub fn describe(
  game game: chess.GameState,
  move move: chess.Move,
) -> Result(String, DescribeError)