This is chess.info, produced by makeinfo version 6.7 from chess.texi. Copyright © 2001, 2002, 2004, 2014 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover Texts being “A GNU Manual,” and with the Back-Cover Texts as in (a) below. A copy of the license is included in the section entitled “GNU Free Documentation License.” (a) The FSF’s Back-Cover Text is: “You have the freedom to copy and modify this GNU manual.” INFO-DIR-SECTION Emacs START-INFO-DIR-ENTRY * Chess: (chess). Chess.el is an Emacs chess client. END-INFO-DIR-ENTRY Copyright © 2001, 2002, 2004, 2014 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover Texts being “A GNU Manual,” and with the Back-Cover Texts as in (a) below. A copy of the license is included in the section entitled “GNU Free Documentation License.” (a) The FSF’s Back-Cover Text is: “You have the freedom to copy and modify this GNU manual.”  File: chess.info, Node: Top, Next: The chess.el library, Up: (dir) Emacs Chess: chess.el ********************* ‘Chess.el’ is an Emacs chess client and library, designed to be used for writing chess-related programs, or for playing games of chess against various chess engines, including Internet servers. The library can be used for analyzing variations, browsing historical games, or a multitude of other purposes. The purpose of this manual is to help you understand how ‘chess.el’ is structured for use as a library, and also how to use it as a client. * Menu: * The chess.el library:: Basic objects required to deal with Chess * Modules:: The module-system explained * Chessboard displays:: Different types of chessboards in a buffer * Engines:: Internal and external chess-playing engines * Chess Session:: Tying it all together * Internet Chess Servers:: Playing chess with other people * GNU Free Documentation License:: * Concept Index:: * Function and Variable Index:: * Key Index::  File: chess.info, Node: The chess.el library, Next: Modules, Up: Top 1 The ‘chess.el’ library ************************ This chapter documents the low-level aspects of ‘chess.el’, mostly targeting developers interested in understanding the underlying APIs. *Note Chessboard displays::, and the chapters following it, if you are interested in the more user-visible aspects of ‘chess.el’. * Menu: * Positions:: * Plies:: * Variations:: * Games:: * Collections:: * Chess Opening Books::  File: chess.info, Node: Positions, Next: Plies, Up: The chess.el library 1.1 Positions ============= A chess “position” is a given layout of pieces on a chess board, also reflecting which “side” (i.e., player) is next to move, and what privileges are currently available to each side (castling short or long, en passant capture, etc). A position may be represented in ASCII using FEN (or EPD), or graphically by displaying a chess board. It is rather inconvenient to render them verbally. The position can be represented on a remote terminal using X windows, or by transmitting the FEN string via a network connection or clipboard, to another chess board rendering tool. It may of course also be represented physically, by setting up the pieces to match the FEN specification. Chess puzzles are most often provided as a set of positions. * Menu: * Creating positions:: * Position coordinates:: * Position details:: * Annotations:: * FEN notation:: * EPD notation::  File: chess.info, Node: Creating positions, Next: Position coordinates, Up: Positions 1.1.1 Creating positions ------------------------ -- Function: chess-pos-create &optional blank Create a new chess position, set at the starting position. If BLANK is non-‘nil’, all of the squares will be empty. The current side-to-move is always white. -- Function: chess-pos-copy position Copy the given chess POSITION. If there are annotations or EPD opcodes set, these lists are copied as well, so that the two positions do not share the same lists. -- Variable: chess-starting-position Starting position of a chess game. -- Function: chess-fischer-random-position Generate a Fischer Random style position.  File: chess.info, Node: Position coordinates, Next: Position details, Prev: Creating positions, Up: Positions 1.1.2 Position coordinates -------------------------- First of all, position coordinates use a coordinate system of octal indices, where the index ‘?\044’ signifies rank 4 file 4 (i.e., "e4"). Rank is numbered 0 to 7, top to bottom, and file is 0 to 7, left to right. -- Function: chess-index-rank index Return the rank component of the given INDEX. -- Function: chess-index-file index Return the file component of the given INDEX. -- Function: chess-rf-to-index rank file Convert RANK and FILE coordinates into an octal index. For those who wish to use ASCII coordinates, such as "e4", there are two conversion functions: -- Function: chess-coord-to-index coord Convert a COORD string into an index value. -- Function: chess-index-to-coord index Convert the chess position INDEX into a coord string. For fast manipulation of chess position indices, the following constants and functions are provided: For queens and rooks: -- Constant: chess-direction-north Signify one step north, as seen from the perspective of the white player. -- Constant: chess-direction-east Signify one step east, as seen from the perspective of the white player. -- Constant: chess-direction-south Signify one step south, as seen from the perspective of the white player. -- Constant: chess-direction-west Signify one step west, as seen from the perspective of the white player. For queens and bishops: -- Constant: chess-direction-northeast Signify one step northeast, as seen from the perspective of the white player. -- Constant: chess-direction-southeast Signify one step southeast, as seen from the perspective of the white player. -- Constant: chess-direction-southwest Signify one step southwest, as seen from the perspective of the white player. -- Constant: chess-direction-northwest Signify one step northwest, as seen from the perspective of the white player. -- Function: chess-next-index index direction Create a new INDEX from an old one, by advancing it into DIRECTION. If the resulting index is not valid (outside the board), ‘nil’ is returned. Due to the underlying technique used to efficiently detect off-board squares, a direction specifier should at most do two steps in any direction. Directions can be combined, so that ‘(* chess-direction-north 2)’ will give a typical initial white pawn push.  File: chess.info, Node: Position details, Next: Annotations, Prev: Position coordinates, Up: Positions 1.1.3 Position details ---------------------- Given an octal index value, you can look up what’s on a particular square, or set that square’s value: -- Function: chess-pos-piece position index Return the piece on POSITION at INDEX. -- Function: chess-pos-piece-p position index piece-or-color Return non-‘nil’ if the given PIECE-OR-COLOR is at POSITION/INDEX. If PIECE-OR-COLOR is ‘t’ for white or ‘nil’ for black, any piece of that color will do. -- Function: chess-pos-set-piece position index piece Set the piece on POSITION at INDEX to PIECE. PIECE must be one of ‘?K’, ‘?Q’, ‘?N’, ‘?B’, ‘?R’, or ‘?P’ for white pieces, or one of the corresponding lowercase letters for black pieces. -- Function: chess-pos-search position piece-or-color Look anywhere on POSITION for PIECE-OR-COLOR, returning all coordinates. If PIECE-OR-COLOR is ‘t’ for white or ‘nil’ for black, any piece of that color will do. -- Function: chess-pos-search* position &rest pieces Look on POSITION for any of PIECES. The result is an alist where each element looks like ‘(PIECE . INDICES)’. Pieces which did not appear in POSITION will be present in the resulting alist, but the ‘cdr’ of their entries will be ‘nil’. -- Function: chess-search-position position target piece &optional check-only no-castling Look on POSITION from TARGET for a PIECE that can move there. This routine looks along valid paths of movement for PIECE. It differs from ‘chess-pos-search’, which is a more basic function that doesn’t take piece movement into account. If PIECE is ‘t’ or ‘nil’, valid piece movements for any piece of that color will be considered (‘t’ for white, ‘nil’ for black). Otherwise, the letter-case of the PIECE determines color. The return value is a list of candidates, which means a list of indices that indicate where a piece may have moved from. If CHECK-ONLY is non-‘nil’ and PIECE is either ‘t’ or ‘nil’, only consider pieces which can give check (not the opponent’s king). If NO-CASTLING is non-‘nil’, do not consider castling moves. -- Function: chess-pos-can-castle position side Return whether the king on POSITION can castle on SIDE. The SIDE argument must be either ‘?K’ for the king side, or ‘?Q’ for the queen side (use lowercase to query if black can castle). -- Function: chess-pos-set-can-castle position side value Set whether the king can castle on the given POSITION on SIDE. See ‘chess-pos-can-castle’. It is only necessary to call this function if setting up a position manually. Note that all newly created positions have full castling privileges set, unless the position is created blank, in which case castling privileges are unset. See ‘chess-pos-create’. -- Function: chess-pos-en-passant position Return the index of any pawn on POSITION that can be captured en passant. Returns ‘nil’ if en passant is unavailable. -- Function: chess-pos-set-en-passant position index Set the index of any pawn on POSITION that can be captured en passant. -- Function: chess-pos-status position Return whether the side to move in the POSITION is in a special state. Return ‘nil’ if not, otherwise one of the keywords: ‘:check’, ‘:checkmate’ or ‘:stalemate’. -- Function: chess-pos-set-status position value Set whether the side to move in POSITION is in a special state. The VALUE should either be ‘nil’, to indicate that the POSITION is normal, or one of the symbols: ‘check’, ‘checkmate’, ‘stalemate’. -- Function: chess-pos-side-to-move position Return the color whose move it is in POSITION. -- Function: chess-pos-set-side-to-move position color Set the color whose move it is in POSITION. -- Function: chess-pos-passed-pawns position color &optional pawn-indices If COLOR has Passed Pawns in POSITION, return a list of their indices. Optionally, if INDICES is non-‘nil’, those indices are considered as candidates. A Pawn whose advance to the eighth rank is not blocked by an opposing Pawn in the same file and who does not have to pass one on an adjoining file is called a passed Pawn. -- Variable: chess-pos-always-white When set, it is assumed that white is always on move. This is really only useful when setting up training positions. This variable automatically becomes buffer-local when changed. -- Function: chess-pos-move position &rest changes Move a piece on the POSITION directly, using the indices in CHANGES. This function does not check any rules, it only makes sure you are not trying to move a blank square.  File: chess.info, Node: Annotations, Next: FEN notation, Prev: Position details, Up: Positions 1.1.4 Annotations ----------------- -- Function: chess-pos-annotations position Return the list of annotations for this position. -- Function: chess-pos-add-annotation position annotation Add an annotation for this position.  File: chess.info, Node: FEN notation, Next: EPD notation, Prev: Annotations, Up: Positions 1.1.5 FEN notation ------------------ “FEN” (Forsyth-Edwards Notation) encodes a chess position using a simple string. The format is: POSITION SIDE CASTLING EN-PASSANT The POSITION gives all eight ranks, by specifying a letter for each piece in the position, and a number for any intervening spaces; ranks are separated by slashes. Trailing spaces need not be counted. Uppercase letters signify white pieces, and lowercase black. For example, if your position only had a black king on d8, your POSITION string would be: 3k//////// for the three spaces (a, b and c file), the black king, and then all the remaining ranks (which are all empty, so their spaces can be ignored). The SIDE is ‘w’ or ‘b’, to indicate whose move it is. The CASTLING can contain ‘K’, ‘Q’, ‘k’ or ‘q’, to signify whether the white or black king can still castle on the king or queen side. If neither color can castle on any side, ‘-’ should be provided. The EN-PASSANT signifies the target square of an en passant capture, such as ‘e3’ or ‘a6’. -- Function: chess-fen-to-pos fen Convert the FEN string FEN to a chess position. -- Function: chess-pos-to-fen position &optional full Convert a chess POSITION to a FEN string. If FULL is non-‘nil’, represent trailing spaces as well. This is how the starting position looks like: (chess-pos-to-fen chess-starting-position) ⇒ "rnbqkbnr/pppppppp/////PPPPPPPP/RNBQKBNR w KQkq -" Some external programs might have problems parsing terse FEN strings. If you are unsure, use the more verbose form: (chess-pos-to-fen chess-starting-position t) ⇒ "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq -"  File: chess.info, Node: EPD notation, Prev: FEN notation, Up: Positions 1.1.6 EPD notation ------------------ “EPD” (Extended Position Description) is a standard for describing chess positions along with an extended set of structured attribute values using the ASCII character set. It is intended for data and command interchange among chess-playing programs. It is also intended for the representation of portable opening library repositories. A single EPD uses one text line of variable length composed of four data fields, followed by zero or more operations. The four fields of the EPD specification are the same as the first four fields of the FEN specification (*note FEN notation::). A text file composed exclusively of EPD data records should have a file name with the ‘.epd’ extension. -- Function: chess-epd-to-pos &optional string Convert extended position description STRING to a chess position. If STRING is not specified, look for an EPD string in the current buffer, and advance point after the correctly parsed position. -- Function: chess-pos-to-epd position Convert a chess POSITION to a string representation in extended position description format. -- Function: chess-epd-read-file file Return a list of positions contained in FILE. * Menu: * Operations:: * Opcode "acd" analysis count depth:: * Opcode "acn" analysis count nodes:: * Opcode "acs" analysis count seconds:: * Opcode "am" avoid move(s):: * Opcode "bm" best move(s)::  File: chess.info, Node: Operations, Next: Opcode "acd" analysis count depth, Up: EPD notation 1.1.6.1 Operations .................. An EPD operation is composed of an opcode followed by zero or more operands, and terminated by a semicolon. Multiple operations are separated by a single space character. If there is at least one operation present in an EPD record, it is separated from the last (fourth) data field by a single space character. Some opcodes that allow for more than one operand may have special ordering requirements for the operands. For example, the ‘pv’ (predicted variation) opcode requires its operands (moves) to appear in the order in which they would be played. All other opcodes that allow for more than one operand should have operands appearing in ASCII order. An example of the latter set is the ‘bm’ (best move[s]) opcode; its operands are moves that are all immediately playable from the current position.  File: chess.info, Node: Opcode "acd" analysis count depth, Next: Opcode "acn" analysis count nodes, Prev: Operations, Up: EPD notation 1.1.6.2 Opcode ‘acd’ analysis count depth ......................................... The opcode ‘acd’ takes a single non-negative integer operand. It is used to represent the depth of the ply (*note Plies::) examined in an analysis.  File: chess.info, Node: Opcode "acn" analysis count nodes, Next: Opcode "acs" analysis count seconds, Prev: Opcode "acd" analysis count depth, Up: EPD notation 1.1.6.3 Opcode ‘acn’ analysis count nodes ......................................... The opcode ‘acn’ takes a single non-negative integer operand. It is used to represent the number of nodes examined in an analysis. Note that the value may be quite large for some extended searches, and so use of (at least) a long (four byte) representation is suggested.  File: chess.info, Node: Opcode "acs" analysis count seconds, Next: Opcode "am" avoid move(s), Prev: Opcode "acn" analysis count nodes, Up: EPD notation 1.1.6.4 Opcode ‘acs’ analysis count seconds ........................................... The opcode ‘acs’ takes a single non-negative integer operand. It is used to represent the number of seconds used for an analysis. Note that the value may be quite large for some extended searches, and so use of (at least) a long (four byte) representation is suggested.  File: chess.info, Node: Opcode "am" avoid move(s), Next: Opcode "bm" best move(s), Prev: Opcode "acs" analysis count seconds, Up: EPD notation 1.1.6.5 Opcode ‘am’ avoid move(s) ................................. The opcode ‘am’ indicates a set of zero or more moves, all immediately playable from the current position, that are to be avoided in the opinion of the EPD writer. Each operand is a SAN move; they appear in ASCII order.  File: chess.info, Node: Opcode "bm" best move(s), Prev: Opcode "am" avoid move(s), Up: EPD notation 1.1.6.6 Opcode ‘bm’ best move(s) ................................ The opcode ‘bm’ indicates a set of zero or more moves, all immediately playable from the current position, that are judged to the best available by the EPD writer. Each operand is a SAN move; they appear in ASCII order.  File: chess.info, Node: Plies, Next: Variations, Prev: Positions, Up: The chess.el library 1.2 Plies ========= A “ply” is the differential between two positions. In other words, it is the coordinate transformations applied to one position in order to arrive at the following position. It is also informally called "a move". A ply may be represented in ASCII by printing the FEN string of the base position, and then printing the positional transformation in algebraic notation. Since the starting position is usually known, the FEN string is optional. A ply may be represented graphically by moving the chess piece(s) involved. It may be rendered verbally by voicing which piece is to move, where it will move to, and what will happen a result of the move (piece capture, check, etc). Plies may be sent over network connections, postal mail, e-mail, etc., so long as the current position is maintained at both sides. Transmitting the base position’s FEN string along with the ply offers a form of confirmation during the course of a game. * Menu: * Creating plies:: * Ply details:: * The "next" position:: * Algebraic notation::  File: chess.info, Node: Creating plies, Next: Ply details, Up: Plies 1.2.1 Creating plies -------------------- -- Function: chess-ply-create position &optional valid-p &rest changes Create a ply from the given POSITION by applying the supplied CHANGES. This function will guarantee the resulting ply is valid, and will also annotate the ply with ‘:check’ or other modifiers as necessary. It will also extend castling, and will prompt for a promotion piece. Note: Do not pass in the rook move if CHANGES represents a castling maneuver. -- Function: chess-legal-plies position &rest keywords Return a list of all valid plies in POSITION. The allowed KEYWORDS are: ‘:any’ Return ‘t’ if any piece can move at all. ‘:color BOOLEAN’ If BOOLEAN is ‘t’, return plies for white, if ‘nil’, return plies for black. ‘:piece CHARACTER’ Return plies for a specific piece designated by CHARACTER. ‘:file FILE’ Given a FILE, a number (0-7), return plies for any piece or color present on that FILE. ‘:piece’ or ‘:color’ must be present. ‘:index INDEX’ Return plies for the piece at INDEX. ‘:target INDEX’ Return plies that go to a specific coordinate specified by INDEX. ‘:candidates INDEX...’ If provided, only consider the source coordinates specified by the indices. These will constrain the plies generated to those matching the above criteria. NOTE: All of the returned plies will reference the same copy of the position object passed in.  File: chess.info, Node: Ply details, Next: The "next" position, Prev: Creating plies, Up: Plies 1.2.2 Ply details ----------------- -- Function: chess-ply-pos ply Return the base position associated with PLY. -- Function: chess-ply-set-pos ply position Set the base position of PLY. -- Function: chess-ply-changes Return the coordinate transformations and keywords associated with this PLY. Value is a list made of a pair of indices (or two pairs, in case of castling) followed by optional keywords. -- Function: chess-ply-set-changes Set the coordinate transformations and keywords associated with this PLY. -- Function: chess-ply-source ply Return the source square index value of PLY. -- Function: chess-ply-target ply Return the target square index value of PLY. For example, here is how to find the source square of a freshly created ply: (chess-ply-source (chess-ply-create chess-starting-position nil (chess-coord-to-index "e2") (chess-coord-to-index "e4"))) ⇒ 52  File: chess.info, Node: The "next" position, Next: Algebraic notation, Prev: Ply details, Up: Plies 1.2.3 The “next” position ------------------------- -- Function: chess-ply-next-pos ply Return the position that results from executing PLY. -- Function: chess-ply-final-p ply Return non-‘nil’ if this is the last ply of a game/variation.  File: chess.info, Node: Algebraic notation, Prev: The "next" position, Up: Plies 1.2.4 Algebraic notation ------------------------ A thing to deal with in chess is algebraic move notation, such as ‘Nxf3+’. This notation is a shorthand way of representing where a piece is moving from and to, by specifying the piece involved, where it’s going, and whether or not a capture or check is involved. You can convert from algebraic notation to a ply using the following function: -- Function: chess-algebraic-to-ply position move &optional trust Convert the algebraic notation MOVE for POSITION to a ply. If optional argument TRUST is non-‘nil’, accept check or checkmate symbols (‘+’ and ‘#’) as given. The function also checks if a move is valid, and will raise an error if not. To convert from a ply to algebraic notation, use: -- Function: chess-ply-to-algebraic ply &optional type Convert the given PLY to algebraic notation (a string). Optional argument TYPE specifies the kind of algebraic notation to generate: ‘:san’ Generate short (or standard) algebraic notation. This is the default. ‘:lan’ Generate long algebraic notation (like ‘Nb1-c3’). ‘:fan’ Generate figurine algebraic notation (uppercase letters will be replaced by Unicode chess figures). ‘:numeric’ Generate ICCF numeric notation as used in correspondence chess (like ‘2133’). Lastly, there is a regexp for quickly checking if a string is in algebraic notation or not, or searching out algebraic strings in a buffer: -- Variable: chess-algebraic-regexp A regular expression that matches all possible algebraic moves. This regexp handles short, long and figurine algebraic notation.  File: chess.info, Node: Variations, Next: Games, Prev: Plies, Up: The chess.el library 1.3 Variations ============== A “variation” is a sequence of plies that occur after some starting position. If the starting position represents the initial setup of a chess board, and if the final ply results in completion of the game, it is called “the main variation”. Otherwise, variations typically represented interesting tangents during a game—but not actually played—as envisioned by the player, an annotator, or someone studying the game. Variations may be represented in ASCII by stating the FEN string for starting position, followed by the list of plies that follow that position. They are difficult to represent graphically, except for showing each position in turn with a slight pause between—or by allowing the user to navigate each of the subsequent positions in turn. They may be represented verbally by announcing each of the plies in turn, as mentioned above. * Menu: * Creating variations:: * Variation positions:: * Variation plies:: * Making a move in a variation::  File: chess.info, Node: Creating variations, Next: Variation positions, Up: Variations 1.3.1 Creating variations ------------------------- -- Function: chess-var-create &optional position Create a new chess variation object. Optionally, use the given starting POSITION.  File: chess.info, Node: Variation positions, Next: Variation plies, Prev: Creating variations, Up: Variations 1.3.2 Variation positions ------------------------- -- Function: chess-var-pos variation &optional index Return the position related to VARIATION’s INDEX ply. -- Function: chess-var-index variation Return the VARIATION’s current position index. -- Function: chess-var-seq variation Return the current VARIATION sequence. -- Function: chess-var-side-to-move variation &optional index Return the color whose move it is in VARIATION at INDEX (or at the last position of VARIATION if INDEX is ‘nil’).  File: chess.info, Node: Variation plies, Next: Making a move in a variation, Prev: Variation positions, Up: Variations 1.3.3 Variation plies --------------------- -- Function: chess-var-ply variation &optional index Return VARIATION’s INDEXth ply. -- Function: chess-var-plies variation Return the plies of VARIATION. -- Function: chess-var-to-algebraic variation &optional long Reveal the plies of VARIATION by converting them to algebraic notation.  File: chess.info, Node: Making a move in a variation, Prev: Variation plies, Up: Variations 1.3.4 Making a move in a variation ---------------------------------- -- Function: chess-var-move variation ply Make a move in the current VARIATION by applying the changes of PLY. This creates a new position and adds it to the main variation. The ‘changes’ of the last ply reflect whether the var is currently in progress (‘nil’), if it is drawn, resigned, mate, etc. -- Function: chess-var-add-ply variation ply Add the given PLY to VARIATION.  File: chess.info, Node: Games, Next: Collections, Prev: Variations, Up: The chess.el library 1.4 Games ========= A “game” includes its main variation, incidental information about the game (who played it, where, when, who won, etc.), and any sub-variations of interest to those studying the game afterwards. “Game tags” is an alist that associates arbitrary English tag names to their values. A game may be represented in ASCII using “PGN” (Portable Game Notation). Representing them graphically or verbally is similar to what is done for variations (*note Variations::). -- Function: chess-game-add-hook game function &optional data prepend Add to GAME an event hook FUNCTION. -- Function: chess-game-add-ply game ply Add PLY to the main variation of GAME. -- Function: chess-game-hooks game Return the event hooks associated with GAME. -- Function: chess-game-plies game Return the main variation of GAME as a list of plies. -- Function: chess-game-remove-hook game function &optional data Remove from GAME all event hooks that match FUNCTION. If DATA is specified, only remove hooks with matching associated data. -- Function: chess-game-run-hooks game &rest args Run the event hooks of GAME and pass it ARGS. -- Function: chess-game-set-hooks game hooks Set the event hooks associated with GAME. -- Function: chess-game-set-plies game plies Set the list of plies which represents the main variation of GAME. * Menu: * Creating games:: * Game tags:: * Game positions:: * Game plies:: * Making a move:: * PGN notation::  File: chess.info, Node: Creating games, Next: Game tags, Up: Games 1.4.1 Creating games -------------------- -- Function: chess-game-create &optional position tags Create a new chess game object. Optionally use the given starting POSITION. TAGS is the starting set of game tags (which can always be changed later using the various tag-related methods).  File: chess.info, Node: Game tags, Next: Game positions, Prev: Creating games, Up: Games 1.4.2 Game tags --------------- -- Function: chess-game-tags game Return the tags alist associated with GAME. -- Function: chess-game-set-tags game tags Set the tags alist associated with GAME. After the TAGS alist was set the ‘set-tags’ event is triggered. -- Function: chess-game-tag game tag Return the value for TAG in GAME. -- Function: chess-game-set-tag game tag value Set the TAG for GAME to VALUE. -- Function: chess-game-del-tag game tag Delete the specified TAG from GAME.  File: chess.info, Node: Game positions, Next: Game plies, Prev: Game tags, Up: Games 1.4.3 Game positions -------------------- -- Function: chess-game-pos game &optional index Return the current position of GAME or a position of a given INDEX. -- Function: chess-game-index game Return the GAME’s current position index. -- Function: chess-game-seq game Return the current GAME sequence number. -- Function: chess-game-side-to-move game &optional index Return the side, specified as color, whose move it is in GAME at INDEX (or at the last position if INDEX is ‘nil’). Value is ‘t’ for white and ‘nil’ for black.  File: chess.info, Node: Game plies, Next: Making a move, Prev: Game positions, Up: Games 1.4.4 Game plies ---------------- -- Function: chess-game-ply game &optional index Return a ply of GAME. If INDEX is non-‘nil’, the last played ply is returned.  File: chess.info, Node: Making a move, Next: PGN notation, Prev: Game plies, Up: Games 1.4.5 Making a move ------------------- -- Function: chess-game-move game ply Make a move in the current GAME using PLY. This creates a new position and adds it to the main variation. The ‘changes’ of the last ply reflect whether the game is currently in progress (‘nil’), if it is drawn, resigned, mate, etc.  File: chess.info, Node: PGN notation, Prev: Making a move, Up: Games 1.4.6 PGN notation ------------------ -- Function: chess-pgn-to-game &optional string Convert the PGN notation at point into a chess game. Optionally use the supplied STRING instead of the current buffer. -- Function: chess-game-to-pgn game &optional indented to-string Convert a chess GAME to PGN notation. If INDENTED is non-‘nil’, indent the move texts. If TO-STRING is non-‘nil’, return a string instead of inserting the resulting PGN text. -- Function: chess-pgn-insert-plies game index plies &optional for-black indented no-annotations _NYI_: Still have to implement the INDENTED argument. * Menu: * PGN mode::  File: chess.info, Node: PGN mode, Up: PGN notation 1.4.6.1 PGN mode ................ -- Function: chess-pgn-visualize Visualize the move for the PGN game under point. This does not require that the buffer be in PGN mode.  File: chess.info, Node: Collections, Next: Chess Opening Books, Prev: Games, Up: The chess.el library 1.5 Collections =============== A “collection” is a set of games archived for later perusal. A set of games conceptually represents a large tree of branching variations, and can be used for studying current theory, examining Master preferences, etc. ‘Chess.el’ itself does not attempt to provide library services, nor does it ever represent library collections in memory. Instead, it interacts with a chess database engine for the purpose of storing and retrieving games from the library, or performing library-wide analyses and searches. * Menu: * Opening Databases:: * Querying Databases:: * Modifying Databases:: * Finalizing Databases:: * Database Modules::  File: chess.info, Node: Opening Databases, Next: Querying Databases, Up: Collections 1.5.1 Opening Databases ----------------------- -- Variable: chess-database-modules List of database modules to try when ‘chess-database-open’ is called. -- Function: chess-database-open file &optional module Open a game database specified by FILE. You can optionally specify the database MODULE to use. Returns the opened database object, or nil.  File: chess.info, Node: Querying Databases, Next: Modifying Databases, Prev: Opening Databases, Up: Collections 1.5.2 Querying Databases ------------------------ -- Function: chess-database-filename database Return the filename of an already opened DATABASE. -- Function: chess-database-read database index Return from DATABASE the chess game object at INDEX. -- Function: chess-database-query database &rest terms Run a query on DATABASE. The TERMS are partly dependent on the chess-database module in use. For the ‘chess-scid’ module, using ‘tree-search GAME’ means perform a tree search on the last position of GAME.  File: chess.info, Node: Modifying Databases, Next: Finalizing Databases, Prev: Querying Databases, Up: Collections 1.5.3 Modifying Databases ------------------------- -- Function: chess-database-read-only-p database Return non-‘nil’ if DATABASE is read only.  File: chess.info, Node: Finalizing Databases, Next: Database Modules, Prev: Modifying Databases, Up: Collections 1.5.4 Finalizing Databases --------------------------  File: chess.info, Node: Database Modules, Prev: Finalizing Databases, Up: Collections 1.5.5 Database Modules ---------------------- Currently, there are two subclasses of the above defined database base-class: * Menu: * chess-file:: * chess-scid::  File: chess.info, Node: chess-file, Next: chess-scid, Up: Database Modules 1.5.5.1 chess-file .................. This module does not use an external chess database program to store and retrieve games. It uses the PGN of EPD format parsing routines provided in ‘chess-pgn.el’ and ‘chess-epd.el’ to implement collections for ordinary PGN and EPD files. EPD file collections are represented as a collection of games originating at the given position. One might argue that conceptually, they represent a collection of positions, but it is more convenient to merge all collections into one uniform concept.  File: chess.info, Node: chess-scid, Prev: chess-file, Up: Database Modules 1.5.5.2 chess-scid .................. This module implements basic reading and writing functionality for “SCID” (Shane’s Chess Information Database) files.  File: chess.info, Node: Chess Opening Books, Prev: Collections, Up: The chess.el library 1.6 Chess Opening Books ======================= There are two different modules/libraries provided for looking up chess positions in opening books. * Menu: * ECO Classification:: * Polyglot opening book format support::  File: chess.info, Node: ECO Classification, Next: Polyglot opening book format support, Up: Chess Opening Books 1.6.1 ECO Classification ------------------------ Module ‘chess-eco’ provides a database of well known names for chess opening positions. If this module is activated (see variable ‘chess-default-modules’), known chess opening positions will be announced in the minibuffer during a game.  File: chess.info, Node: Polyglot opening book format support, Prev: ECO Classification, Up: Chess Opening Books 1.6.2 Polyglot opening book format support ------------------------------------------ The popular and freely documented Polyglot opening book format is supported. There is a default polyglot book file shipped with ‘chess.el’ to support engines which do not have built-in support for looking up positions in opening books (such as some UCI protocol based engines). -- User Option: chess-polyglot-book-file Path to default polyglot book file. -- Variable: chess-polyglot-book If non-‘nil’, the buffer holding the currently loaded polyglot book data. This is used by UCI based engine modules as well as the internal AI. -- Function: chess-polyglot-book-open file Open a polyglot book FILE. Returns a buffer object which contains the binary data. -- Function: chess-polyglot-book-plies book position Return a list of plies found in BOOK for POSITION. The resulting list is ordered, most interesting plies come first. The ‘:polyglot-book-weight’ ply keyword is used to store the actual move weights. Use ‘chess-ply-keyword’ on elements of the returned list to retrieve them. -- Function: chess-polyglot-book-ply book position &optional strength If non-‘nil’, a (randomly picked) ply from BOOK for POSITION. Random distribution is defined by the relative weights of the found plies. If non-‘nil’, STRENGTH defines the bias towards better moves. A value below 1.0 will penalize known good moves while a value above 1.0 will prefer known good moves. The default is the value of ‘chess-polyglot-book-strength’. A strength value of 0.0 will completely ignore move weights, and evenly distribute the probability that a move gets picked.  File: chess.info, Node: Modules, Next: Chessboard displays, Prev: The chess.el library, Up: Top 2 Modules ********* Positions, plies and variations are typically accessed in reference to a game object, which has a main variation containing the plies and positions that represent the number of moves made within that game up to the final position. Another thing that the game object does is to manage events that occur within that game. If a move is made from the final position, for example, it will cause a new ply to be created, adding it to the end of the main variation. Then, a ‘move’ event is triggered within the game and passed to any chess modules which are currently associated with that game. The concept of modules allows far more complex aspects of chess playing to be dealt with, while allowing the library itself to still operate solely in terms of the game object. For example, although the plies of a game object contain all the information the computer needs to follow the game, a user needs much more. He wants to see the pieces move. To support this, a display module (*note Chessboard displays::) can be created, and linked to the game. The first effect of this association will be to create a chess board display and show the game’s final position on it. Now whenever plies are added to the game, the chess board will be updated to show the effect of that move on the board. The display module realizes that a move has been made by receiving the ‘move’ event which is passed to all modules associated with the game object. There may be any number of modules associated with a chess game, and they may do anything you like. Basically, for a module called ‘chess-sample’, a function must exist called ‘chess-sample-handler’. This takes two or more arguments: a game object, the event symbol, and whatever other arguments were passed along with the event symbol. When an event is triggered on a game object (this may happen as a byproduct of manipulating the game, or events may be manually generated), every associated module, in order, is called with that event and whatever arguments were passed along with the event. The game object is passed also, so that the module knows which game this event has occurred in reference to. Once called, the module can do whatever it likes. Some events expect certain values to be returned, to indicate success or failure in processing the event. There are many different events, each depicting something specific that might happen in the context of playing or manipulating a chess game. Some events relate only to the chess game itself, some are triggered by the various chess engines that might be associated with that game. Modules may even trigger events in response to event. The game itself remains unaware of events, except for the fact that it will pass them along to every module associated with that game. This is how displays get updated, for example, because once a ‘move’ event is triggered, each display knows that it must now look at the new final position and update its display. It may even trigger new events special to displays, to cause a refresh to happen after update calculations have been performed, for example. All such details are left to the module, and the game does not interfere with such intra-module messaging. Looked at as an object-oriented design, these are typical polymorphic events. Certain generic situations frequently occur, such as moves, which trigger events so that everyone concerned with the game can be updated as to the move that occurred. This way, no one need to actively query the game to find out if something new has happened. The game will notify every listening module by sending an event. The core library, which consists of code to manipulate games, does not define any modules. The rest of the ‘chess.el’ library is strictly a set of module implementations, of various types. Display modules react to moves, and may modify the game based on user input; engine modules react to moves by notifying the engine of the move; network client modules react to moves by sending the move text over the network. Engine and network modules may also trigger new events when the engine or network player has decided on their move, and this move is then applied to the game object. At the moment, no negotiation is done to determine which module may modify the game object. All modules have equal privilege. This means it is the programmer’s duty not to associate conflicting modules with a single game object. If two artificial intelligence engines were linked, for example, they would quickly start stepping on each other’s toes. But it is perfectly fine to have one artificial intelligence engine, and another passive engine whose only purpose is to relay the moves to a networked observer on another computer. The possibilities are endless. Modules are very easy to write, although engines and displays are rather different from each other in their principles. There is a base engine, and a base display, which receive the same events as any other module. But then there are derived engines and derived displays which trigger a whole family of events specific to those module types. If you suspect a bug in your module, put a breakpoint in your handler function, and wait for the offending event to come through. Then you can watch what your module does in response to that event. If it leaves the game object alone, it should be easy to locate the problem, since it will always be within the module itself. But if your module also modifies the game object in response to certain events, you may induce a feedback loop that is much more difficult to sort out. Test often and keep in mind that _many_ events might end up coming through as a result of the game changes your module makes! That, in essence, is how the module system works. From the game object’s perspective, it is a very simple mechanism, much like a function ring or a hook. The hook is called at certain points, so that any listener can react to changes in the game. But from each module’s perspective, it is a rich way to allow inter-operation between both passive and reactive modules, all of them acting together to enrich the context of play involving the central game object. The only other rule to be mentioned is that each module instance should be associated with only one game object at a time, although a game object may have unlimited modules of any type linked to it. Otherwise, trying to update a chess board based on input from two different games would get impossible to sort out. Better to create a new board for every game—the way ordinary humans would do it in the real world.  File: chess.info, Node: Chessboard displays, Next: Engines, Prev: Modules, Up: Top 3 Chessboard displays ********************* The previous chapter described all the objects found in chess—positions, plies, variations, games and collections. However, these objects can only be manipulated programmatically using the functions given so far. In order to present them in a meaningful fashion to a human reader, it is necessary to create and use a display object. * Menu: * Generic display manipulation functions:: * Chess display mode:: * Plain ASCII diagram displays:: * ICS1 style ASCII displays:: * Graphical displays::  File: chess.info, Node: Generic display manipulation functions, Next: Chess display mode, Up: Chessboard displays 3.1 Generic display manipulation functions ========================================== -- Function: chess-display-create game style perspective Create a chess display, for displaying chess objects. The GAME is the chess game object to use, STYLE should be the display type to use (a symbol), and PERSPECTIVE determines the viewpoint of the board: if non-‘nil’, the board is viewed from White’s perspective. -- Function: chess-display-active-p Return non-‘nil’ if the displayed chessboard reflects an active game. Basically, it means we are playing, not editing or reviewing. -- Function: chess-display-clear-board Setup the current board for editing. -- Function: chess-display-highlight display &rest args Highlight in DISPLAY the squares given in ARGS on the current position. The ARGS is a list of highlighting modes and position coordinates. The default highlighting mode is ‘:selected’ which is supported by most displays. -- Function: chess-display-invert Invert the perspective of the current chess board. -- Function: chess-display-move display ply Move a piece on DISPLAY, by applying the given PLY. The position of PLY must match the currently displayed position. -- Function: chess-display-perspective display Return the current perspective of DISPLAY. -- Function: chess-display-position display Return the position currently viewed on DISPLAY. -- Function: chess-display-quit Quit the game associated with the current display. -- Function: chess-display-set-game display game &optional index Set the given DISPLAY to display the GAME object, optionally at INDEX. This is the function to call to cause a display to view a game. It will also update all of the listening engines and other displays to also view the same game. -- Function: chess-display-set-perspective display perspective Set PERSPECTIVE of DISPLAY. -- Function: chess-display-set-position display &optional position my-color Set the game associated with DISPLAY to use POSITION and MY-COLOR. -- Function: chess-display-set-variation display variation &optional index Set DISPLAY VARIATION. If INDEX is not specified, this will cause the first ply in the variation to be displayed, with the user able to scroll back and forth through the moves in the variation. Any moves made on the board will extend/change the variation that was passed in. -- Function: chess-display-update display &optional popup Update the chessboard DISPLAY. If POPUP is non-‘nil’, make sure it is visible.  File: chess.info, Node: Chess display mode, Next: Plain ASCII diagram displays, Prev: Generic display manipulation functions, Up: Chessboard displays 3.2 Chess display mode ====================== “Chess display mode” is a special major mode (*note (emacs)Major Modes::) that allows to select pieces to move with the mouse or by moving point to the desired square/piece. Additionally, you can enter moves in a variant of algebraic notation via the keyboard. All the chessboard displays described in following sub-sections share the basic behavior provided by chess display mode. They basically only differ in appearance of the various chessboards. -- User Option: chess-display-highlight-legal If non-nil, highlight valid target squares when a piece is selected. * Menu: * Basic operations:: * Selecting pieces with the keyboard:: * Selecting pieces with the mouse:: * Entering moves with algebraic notation::  File: chess.info, Node: Basic operations, Next: Selecting pieces with the keyboard, Up: Chess display mode 3.2.1 Basic operations ---------------------- ‘C-i’ ‘’ Invert the perspective of the current chess board (‘chess-display-invert’). ‘,’ Show the previous move in the current game (‘chess-display-move-backward’). ‘C-r’ Find previous move which algebraic notation matches a regular expression (‘chess-display-search-backward’). ‘C-s’ Find next move which algebraic notation matches a regular expression (‘chess-display-search-forward’). ‘.’ Show the next move in the current game (‘chess-display-move-forward’). ‘<’ Move to the initial position of the current game (‘chess-display-move-first’). ‘>’ Move to the last position of the current game (‘chess-display-move-last’). ‘C-c C-d’ Offer to draw the current game (‘chess-display-draw’). ‘C-c C-r’ Resign the current game (‘chess-display-resign’). ‘M-w’ ‘C-u M-w’ Copy the currently displayed position to the kill ring as a FEN string (‘chess-display-kill-board’). With prefix argument, copy the current game in PGN to the kill ring. ‘C-y’ Set the current display position via a FEN string from the kill ring (‘chess-display-yank-board’). This is useful to copy positions from one chessboard display to another, as well as quickly setting up a position from a FEN string previously added to the kill ring from somewhere else. ‘X’ Quit this chessboard display (‘chess-display-quit’). This destroys the session (and all related modules) associated with this chessboard display.  File: chess.info, Node: Selecting pieces with the keyboard, Next: Selecting pieces with the mouse, Prev: Basic operations, Up: Chess display mode 3.2.2 Selecting pieces with the keyboard ---------------------------------------- In character based chessboard displays, point can be moved around in the buffer as usual. You can indicate the initial square/piece and the target square/piece by moving point to the desired position and pressing ‘’. ‘’ Select the piece/square currently indicated by point (‘chess-display-select-piece’) to move from/to.  File: chess.info, Node: Selecting pieces with the mouse, Next: Entering moves with algebraic notation, Prev: Selecting pieces with the keyboard, Up: Chess display mode 3.2.3 Selecting pieces with the mouse ------------------------------------- Similarly, you can also use the mouse (if available) to indicate the source and target square of your move. ‘down-mouse-1’ ‘down-mouse-2’ ‘drag-mouse-1’ ‘drag-mouse-2’ Select the piece/square currently indicated by the mouse pointer (‘chess-display-select-piece’) to move from/to.  File: chess.info, Node: Entering moves with algebraic notation, Prev: Selecting pieces with the mouse, Up: Chess display mode 3.2.4 Entering moves with algebraic notation -------------------------------------------- ‘a’ ... ‘h’ ‘1’ ... ‘8’ ‘N’ ‘B’ ‘R’ ‘Q’ ‘K’ ‘x’ ‘=’ Enter move in algebraic notation. The move will be accepted as soon as it is unambiguous. So in most situations, you do not need to type the complete algebraic move string. For instance, if there is only one piece which can be taken by one of your knights, typing ‘N x’ is sufficient to select that move. Additionally, the characters ‘x’ and ‘=’ are optional, as there is no difference between ‘N x e 4’ and ‘N e 4’. Delete the last entered chess move character (‘chess-input-shortcut-delete’). This is useful if you have accidentally typed a wrong character, and the move was not unambiguous yet.  File: chess.info, Node: Plain ASCII diagram displays, Next: ICS1 style ASCII displays, Prev: Chess display mode, Up: Chessboard displays 3.3 Plain ASCII diagram displays ================================ The simplest display style available is ‘chess-plain’, a very customizable ASCII board diagram display. This is how the starting position looks in its default configuration: +---------------+ 8|r n b q k b n r| 7|p p p p p p p p| 6|. . . . . . . .| 5|. . . . . . . .| 4|. . . . . . . .| 3|. . . . . . . .| 2|P P P P P P P P| 1|R N B Q K B N R| +---------------+ a b c d e f g h -- User Option: chess-plain-separate-frame If non-‘nil’, display the chessboard in its own frame. -- User Option: chess-plain-border-style If non-‘nil’, a vector of Characters used to draw borders. Otherwise, omit to draw any border around the chessboard diagram. -- User Option: chess-plain-black-square-char Character used to indicate empty black squares. -- User Option: chess-plain-white-square-char Character used to indicate black white squares. -- User Option: chess-plain-piece-chars Alist of pieces and their corresponding characters. -- User Option: chess-plain-upcase-indicates Defines what an upcase char should indicate. The default is ‘'color’, meaning a upcase char is a white piece, a lowercase char a black piece. Possible values: ‘'color’ (default), ‘'square-color’. If set to ‘'square-color’, an uppercase character indicates a piece on a black square. (Note that you also need to modify ‘chess-plain-piece-chars’ to avoid real confusion.) -- User Option: chess-plain-spacing Number of spaces between files. To customize options of ‘chess-plain’, use ‘M-x customize-group chess-plain ’.  File: chess.info, Node: ICS1 style ASCII displays, Next: Graphical displays, Prev: Plain ASCII diagram displays, Up: Chessboard displays 3.4 ICS1 style ASCII displays ============================= The ‘chess-ics1’ module is a more verbose ASCII chessboard display. This is how the starting position looks with this chessboard display: +---+---+---+---+---+---+---+---+ 8 | r | n | b | q | k | b | n | r | +---+---+---+---+---+---+---+---+ 7 | p | p | p | p | p | p | p | p | +---+---+---+---+---+---+---+---+ 6 | | | | | | | | | +---+---+---+---+---+---+---+---+ 5 | | | | | | | | | +---+---+---+---+---+---+---+---+ 4 | | | | | | | | | +---+---+---+---+---+---+---+---+ 3 | | | | | | | | | +---+---+---+---+---+---+---+---+ 2 | P | P | P | P | P | P | P | P | +---+---+---+---+---+---+---+---+ 1 | R | N | B | Q | K | B | N | R | +---+---+---+---+---+---+---+---+ a b c d e f g h -- User Option: chess-ics1-separate-frame If non-‘nil’, display the chessboard in its own frame. To customize options of ‘chess-ics1’, use ‘M-x customize-group chess-ics1 ’.  File: chess.info, Node: Graphical displays, Prev: ICS1 style ASCII displays, Up: Chessboard displays 3.5 Graphical displays ====================== The graphical chessboard display (‘chess-images’) uses image files to create a visually appealing chessboard in a buffer. -- User Option: chess-images-directory A directory which contains images in XPM format. If you want to draw your own images, each image file must be named ‘COLOR-PIECE.xpm’, where COLOR is either black or white, and PIECE is one of rook, knight, bishop, queen, king or pawn. The only image format currently supported is XPM. -- User Option: chess-images-separate-frame If non-‘nil’, display the chessboard in its own frame. For all customization options of ‘chess-images’, use ‘M-x customize-group chess-images ’.  File: chess.info, Node: Engines, Next: Chess Session, Prev: Chessboard displays, Up: Top 4 Engines ********* “Engines” represent opponents in Chess. The main type of engine interfaces with an external chess program. However, there can be other uses for engine objects, such as providing networked engined for playing with opponent over different types of transports. * Menu: * Common functions:: * The Null Engine:: * AI:: * Crafty:: * Fruit:: * Glaurung:: * GNU Chess:: * Phalanx:: * Sjeng:: * Stockfish::  File: chess.info, Node: Common functions, Next: The Null Engine, Up: Engines 4.1 Common functions ==================== -- Function: chess-engine-create module game &optional response-handler &rest handler-ctor-args Create a new chess engine MODULE (a symbol) associated with GAME. Optionally supply a new RESPONSE-HANDLER. -- Function: chess-engine-set-option engine option value Set ENGINE OPTION to VALUE by invoking its handler with the ‘set-option’ event. -- Function: chess-engine-position engine Return the current position of the game associated with ENGINE. -- Function: chess-engine-command engine event &rest args Call the handler of ENGINE with EVENT (a symbol) and ARGS. -- Function: chess-engine-send engine string Send the given STRING to ENGINE. If ‘chess-engine-process’ is a valid process object, use ‘process-send-string’ to submit the data. Otherwise, the ‘send’ event is triggered and the engine event handler can take care of the data.  File: chess.info, Node: The Null Engine, Next: AI, Prev: Common functions, Up: Engines 4.2 The Null Engine =================== The most basic engine module is ‘chess-none’, a stub module that does nothing. This is useful for a game of chess against another human, where both use the same computer to enter moves and display the current chess position. It can also be useful for creating FEN strings of specific positions. To bring up a chessboard with no active engine attached, use ‘C-u M-x chess none ’.  File: chess.info, Node: AI, Next: Crafty, Prev: The Null Engine, Up: Engines 4.3 AI ====== The AI engine module defines a pure Emacs Lisp implementation of an opponent. Contrary to all other engine modules mentioned later on, it does not require any external programs to be installed. To explicitly select this engine as an opponent, use ‘C-u M-x chess ai ’. -- User Option: chess-ai-depth Defines the default search depth for this engine. -- User Option: chess-ai-quiescence-depth Defines the number of plies to search for a quiet position. This is in addition to ‘chess-ai-depth’. If you’d like to employ the search and evaluation functions provided by this module programmatically, the following function is the top-level entry point. -- Function: chess-ai-best-move position &optional depth eval-fn Find the supposedly best move (ply) for POSITION. DEPTH defaults to the value of ‘chess-ai-depth’.  File: chess.info, Node: Crafty, Next: Fruit, Prev: AI, Up: Engines 4.4 Crafty ========== “Crafty” is a chess program written by Michael Byrne, UAB professor Dr. Robert Hyatt, Tracy Riegle, Peter Skinner and Ted Langreck. It is directly derived from Cray Blitz, winner of the 1983 and 1986 World Computer Chess Championships. If the ‘crafty’ program is installed and can be found in the program search path (‘exec-path’), the ‘chess-crafty’ engine module will automatically detect it. If ‘crafty’ is installed in a non-standard location, variable ‘chess-crafty-path’ can be set to point to its executable file. If you have multiple engines installed you can explicitly select to play against Crafty by invoking ‘C-u M-x chess crafty ’.  File: chess.info, Node: Fruit, Next: Glaurung, Prev: Crafty, Up: Engines 4.5 Fruit ========= “Fruit” is a chess engine developed by Fabien Letouzey. It was commercially available from September 2005 until July 2007. Now it is freeware and you can download it for free from . The development on Fruit by Fabien Letouzey has ceded and it is unlikely to continue. Fruit was vice world computer chess champion 2005. If the ‘fruit’ command is installed and can be found in the program search path (‘exec-path’), the ‘chess-fruit’ engine module will automatically detect it. If Fruit is installed in a non-standard location, variable ‘chess-fruit-path’ can be set to point to its executable file. If you have multiple engines installed you can explicitly select to play against Fruit by invoking ‘C-u M-x chess fruit ’.  File: chess.info, Node: Glaurung, Next: GNU Chess, Prev: Fruit, Up: Engines 4.6 Glaurung ============ “Glaurung” is another freely distributed strong computer chess engine. If the ‘glaurung’ program is installed and can be found in the program search path (‘exec-path’), the ‘chess-glaurung’ engine module will automatically detect it. If Glaurung is installed in a non-standard location, variable ‘chess-glaurung-path’ can be set to point to its executable file. If you have multiple engines installed you can explicitly select to play against Glaurung by invoking ‘C-u M-x chess glaurung ’.  File: chess.info, Node: GNU Chess, Next: Phalanx, Prev: Glaurung, Up: Engines 4.7 GNU Chess ============= “GNU Chess” (http://gnu.org/software/chess/) is free software, licensed under the terms of the GNU General Public License, and is maintained by collaborating developers. As one of the earliest computer chess programs with full source code available, it’s one of the oldest for Unix-based systems and has since been ported to many other platforms. If the ‘gnuchess’ program is installed and can be found in the program search path (‘exec-path’), the ‘chess-gnuchess’ engine module will automatically detect it. If GNU Chess is installed in a non-standard location, variable ‘chess-gnuchess-path’ can be set to point to its executable file. If you have multiple engines installed you can explicitly select to play against GNU Chess by invoking ‘C-u M-x chess gnuchess ’.  File: chess.info, Node: Phalanx, Next: Sjeng, Prev: GNU Chess, Up: Engines 4.8 Phalanx =========== “Phalanx” is an old, popular chess engine, with an interesting history. If the ‘phalanx’ program is installed and can be found in the program search path (‘exec-path’), the ‘chess-phalanx’ engine module will automatically detect it. If Phalanx is installed in a non-standard location, variable ‘chess-phalanx-path’ can be set to point to its executable file. If you have multiple engines installed you can explicitly select to play against Phalanx by invoking ‘C-u M-x chess phalanx ’.  File: chess.info, Node: Sjeng, Next: Stockfish, Prev: Phalanx, Up: Engines 4.9 Sjeng ========= “Sjeng” (http://sjeng.org/) is a championship-winner automated chess engine developed by Gian-Carlo Pascutto from Belgium. While its original version was free, recent developments are for sale. If the ‘sjeng’ program is installed and can be found in the program search path (‘exec-path’), the ‘chess-sjeng’ engine module will automatically detect it. If Sjeng is installed in a non-standard location, variable ‘chess-sjeng-path’ can be set to point to its executable file. If you have multiple engines installed you can explicitly select to play against Sjeng by invoking ‘C-u M-x chess sjeng ’.  File: chess.info, Node: Stockfish, Prev: Sjeng, Up: Engines 4.10 Stockfish ============== “Stockfish” (http://www.stockfishchess.org/) is one of the strongest chess engines in the world, appearing near or at the top of most chess engine rating lists. Stockfish is also free software, licensed under the terms of the GNU General Public License. If the ‘stockfish’ program is installed and can be found in the program search path (‘exec-path’), the ‘chess-stockfish’ engine module will automatically detect it. If Stockfish is installed in a non-standard location, variable ‘chess-stockfish-path’ can be set to point to its executable file. If you have multiple engines installed you can explicitly select to play against Stockfish by invoking ‘C-u M-x chess stockfish ’.  File: chess.info, Node: Chess Session, Next: Internet Chess Servers, Prev: Engines, Up: Top 5 Chess Session *************** A “chess session” assembles all modules mentioned in previous chapters into a working system to interact with. A session typically consists of at least one display module, one engine module, and possibly a number of optional modules. All these modules share a common game object which is used to keep track of the currently active game. -- Function: chess engine disable-popup engine-response-handler &rest engine-ctor-args Play a game against ENGINE. This function constructs all the necessary modules required for a chess session. In particular, it will start ENGINE and create a chess display as configured in ‘chess-default-display’. This is the main entry-point for interactively launching a chessboard display with associated engine. If you want to launch a chess session as part of your own code, the probably more expressive alias ‘chess-session’ might be interesting to use. You can have several active chess sessions. In fact, some features later described in this manual make use of this, *note Internet Chess Servers::. To interactively start a chess session, invoke ‘M-x chess ’. This uses ‘chess-default-display’ to determine the chessboard display to use, and ‘chess-default-engine’ to determine an opponent. If you want to play against a specific engine, provide a prefix argument as in ‘C-u M-x chess ’, which will prompt for an engine module. The module name has the common prefix ‘chess-’ stripped. So you enter ‘gnuchess’ to indicate you’d like to play against the ‘chess-gnuchess’ module.  File: chess.info, Node: Internet Chess Servers, Next: GNU Free Documentation License, Prev: Chess Session, Up: Top 6 Internet Chess Servers ************************ Based on the services provided above, there is also a special mode for communication with Internet Chess Servers. On an Internet Chess Server you can seek to play against other human or computer players, observe other games being played or examined, play tournaments, chat with fellow chess players, participate in team games, or do various other interesting chess related things. A default set of well known servers is defined in the following variable: -- Variable: chess-ics-server-list A list of servers to connect to. The format of each entry is: (SERVER PORT [HANDLE] [PASSWORD-OR-FILENAME] [HELPER] [HELPER ARGS...]) Internet Chess Servers based on FICS (Free Internet Chess Server) (http://www.freechess.org/) and ICC (Internet Chess Club) (http://www.chessclub.com/) are currently supported. * Menu: * Connecting to a server:: * Chess ICS Mode:: * Command History:: * Seeking an opponent for a new game:: * The sought game display:: * Watching other games::  File: chess.info, Node: Connecting to a server, Next: Chess ICS Mode, Up: Internet Chess Servers 6.1 Connecting to a server ========================== To open a new connection to an Internet Chess Server, use: -- Function: chess-ics server port &optional handle password-or-filename helper &rest helper-args Connect to an Internet Chess Server. If called interactively, you will be prompted to enter a server (from ‘chess-ics-server-list’ and possibly identification credentials.  File: chess.info, Node: Chess ICS Mode, Next: Command History, Prev: Connecting to a server, Up: Internet Chess Servers 6.2 Chess ICS Mode ================== The major mode for ICS buffers is Chess ICS mode. Many of its special commands are bound to the ‘C-c’ prefix. Here is a list of ICS mode commands: ‘’ Send the current line as input to the server (‘comint-send-input’). Any prompt at the beginning of the line is omitted. If point is at the end of buffer, this is like submitting the command line in an ordinary interactive shell. However, you can also invoke elsewhere in the ICS buffer to submit the current line as input. ‘C-d’ Either delete a character or send EOF (End Of File) (‘comint-delchar-or-maybe-eof’). Typed at the end of the ICS buffer, this sends EOF to the server and terminates the connection. Typed at any other position in the buffer, this deletes the character at point, as usual. ‘C-c C-a’ Move to the beginning of the line, but after the prompt if any (‘comint-bol-or-process-mark’). If you repeat this command twice in a row, the second time it moves back to the process mark, which is the beginning of the input that you have not yet sent to the server. (Normally that is the same place—the end of the prompt on this line—but after ‘C-c ’ the process mark may be in a previous line.) ‘C-c ’ Accumulate multiple lines of input, then send them together (‘comint-accumulate’). This command inserts a newline before point, but does not send the preceding text as input to the server—at least, not yet. Both lines, the one before this newline and the one after, will be sent together (along with the newline that separates them), when you type . ‘C-c C-u’ Kill all text pending at end of buffer to be sent as input (‘comint-kill-input’). If point is not at end of buffer, this only kills the part of this text that precedes point. ‘C-c C-w’ Kill a word before point (‘backward-kill-word’). ‘C-c C-o’ Delete the last batch of output from an ICS server command (‘comint-delete-output’). This is useful if a server command spews out lots of output that just gets in the way. ‘C-c C-s’ Write the last batch of output from an ICS server command to a file (‘comint-write-output’). With a prefix argument, the file is appended to instead. Any prompt at the end of the output is not written. ‘C-c C-r’ ‘C-M-l’ Scroll to display the beginning of the last batch of output at the top of the window; also move the cursor there (‘comint-show-output’). ‘C-c C-e’ Scroll to put the end of the buffer at the bottom of the window (‘comint-show-maximum-output’). ‘M-x comint-truncate-buffer’ This command truncates the ICS buffer to a certain maximum number of lines, specified by the variable ‘comint-buffer-maximum-size’. Here’s how to do this automatically each time you get output from the server: (add-hook 'comint-output-filter-functions 'comint-truncate-buffer) ICS mode is a derivative of Comint mode, a general-purpose mode for communicating with interactive subprocesses. Most of the features of ICS mode actually come from Comint mode, as you can see from the command names listed above.  File: chess.info, Node: Command History, Next: Seeking an opponent for a new game, Prev: Chess ICS Mode, Up: Internet Chess Servers 6.3 ICS Command History ======================= ICS buffers support two ways of repeating earlier commands. You can use keys like those used for the minibuffer history; these work much as they do in the minibuffer, inserting text from prior commands while point remains always at the end of the buffer. You can move through the buffer to previous inputs in their original place, then resubmit them or copy them to the end. * Menu: * ICS Command Ring:: * ICS History Copying::  File: chess.info, Node: ICS Command Ring, Next: ICS History Copying, Up: Command History 6.3.1 ICS Command History Ring ------------------------------ ‘M-p’ ‘C-’ Fetch the next earlier old ICS command (‘comint-previous-input’). ‘M-n’ ‘C-’ Fetch the next later old ICS command (‘comint-next-input’). ‘M-r’ Begin an incremental regexp search of old ICS commands (‘comint-history-isearch-backward-regexp’). ‘C-c C-x’ Fetch the next subsequent command from the history (‘comint-get-next-from-history’). ‘C-c .’ Fetch one argument from an old ICS command (‘comint-input-previous-argument’). ‘C-c C-l’ Display the buffer’s history of ICS commands in another window (‘comint-dynamic-list-input-ring’). ICS buffers provide a history of previously entered commands. To reuse commands from the history, use the editing commands ‘M-p’, ‘M-n’, ‘M-r’ and ‘M-s’. These work just like the minibuffer history commands (*note (emacs)Minibuffer History::), except that they operate within the ICS buffer rather than the minibuffer. ‘M-p’ fetches an earlier ICS command to the end of the ICS buffer. Successive use of ‘M-p’ fetches successively earlier commands, each replacing any text that was already present as potential input. ‘M-n’ does likewise except that it finds successively more recent ICS commands from the buffer. ‘C-’ works like ‘M-p’, and ‘C-’ like ‘M-n’. The history search command ‘M-r’ begins an incremental regular expression search of previous ICS commands. After typing ‘M-r’, start typing the desired string or regular expression; the last matching ICS command will be displayed in the current line. Incremental search commands have their usual effects—for instance, ‘C-s’ and ‘C-r’ search forward and backward for the next match (*note (emacs)Incremental Search::). When you find the desired input, type to terminate the search. This puts the input in the command line. Any partial input you were composing before navigating the history list is restored when you go to the beginning or end of the history ring. Often it is useful to reexecute several successive ICS commands that were previously executed in sequence. To do this, first find and reexecute the first command of the sequence. Then type ‘C-c C-x’; that will fetch the following command—the one that follows the command you just repeated. Then type to reexecute this command. You can reexecute several successive commands by typing ‘C-c C-x ’ over and over. The command ‘C-c .’ (‘comint-input-previous-argument’) copies an individual argument from a previous command, like ‘ .’ in Bash. The simplest use copies the last argument from the previous ICS command. With a prefix argument N, it copies the Nth argument instead. Repeating ‘C-c .’ copies from an earlier ICS command instead, always using the same value of N (don’t give a prefix argument when you repeat the ‘C-c .’ command). These commands get the text of previous ICS commands from a special history list, not from the ICS buffer itself. Thus, editing the ICS buffer, or even killing large parts of it, does not affect the history that these commands access.  File: chess.info, Node: ICS History Copying, Prev: ICS Command Ring, Up: Command History 6.3.2 ICS History Copying ------------------------- ‘C-c C-p’ Move point to the previous prompt (‘comint-previous-prompt’). ‘C-c C-n’ Move point to the following prompt (‘comint-next-prompt’). ‘C-c ’ Copy the input command at point, inserting the copy at the end of the buffer (‘comint-copy-old-input’). This is useful if you move point back to a previous command. After you copy the command, you can submit the copy as input with . If you wish, you can edit the copy before resubmitting it. If you use this command on an output line, it copies that line to the end of the buffer. ‘Mouse-2’ If ‘comint-use-prompt-regexp’ is ‘nil’ (the default), copy the old input command that you click on, inserting the copy at the end of the buffer (‘comint-insert-input’). If ‘comint-use-prompt-regexp’ is non-‘nil’, or if the click is not over old input, just yank as usual. Moving to a previous input and then copying it with ‘C-c ’ or ‘Mouse-2’ produces the same results—the same buffer contents—that you would get by using ‘M-p’ enough times to fetch that previous input from the history list. However, ‘C-c ’ copies the text from the buffer, which can be different from what is in the history list if you edit the input text in the buffer after it has been sent.  File: chess.info, Node: Seeking an opponent for a new game, Next: The sought game display, Prev: Command History, Up: Internet Chess Servers 6.4 Seeking an opponent for a new game ====================================== After you connected to a server, one of the first things you will want to do is find an opponent for a new game. You can use the ICS command ‘seek’ to announce your availability for a chess game to interested people. For example: fics% seek 10 10 rated This will announce your availability to play a rated game with 10 minutes initial time-control for each player, and 10 seconds added for every move made.  File: chess.info, Node: The sought game display, Next: Watching other games, Prev: Seeking an opponent for a new game, Up: Internet Chess Servers 6.5 The sought game display =========================== There is a special mode for displaying games sought by other users on an Internet Chess Server. Provided you didn’t turn off seek advertisements manually (for instance by setting the seek variable to 0 (off) on the ICS server by issuing "set seek 0"), the first seek advertisement automatically pops up a new window which is in ‘chess-ics-ads-mode’, a derivative of ‘tabulated-list-mode’. -- Function: chess-ics-ads-mode A mode for displaying ICS game seek advertisements. This mode runs the hook ‘chess-ics-ads-mode-hook’, as the final step during initialization. key binding — ——- ? describe-mode RET chess-ics-sought-accept chess-ics-sought-accept In this buffer, use ‘mouse-2’ or ‘’ on a line to accept that particular game and play it.  File: chess.info, Node: Watching other games, Prev: The sought game display, Up: Internet Chess Servers 6.6 Watching other games ======================== You can also watch other games currently being played on ICS. Even services like ‘LectureBot’ from FICS can be used. fics% observe lecturebot You are now observing game 5. Game 5: LectureBot (0) LectureBot (0) unrated untimed 0 0 LectureBot(TD)(----)[5] kibitzes: (Note: A passed pawn is a pawn that does not have enemy pawns blocking the path either on the same or adjacent files). LectureBot(TD)(----)[5] kibitzes: Connected passed pawns are a pain to have to deal with. They are usually a winning advantage if they cannot be blockaded. The blockading piece has to give up duties elsewhere. It's almost like being a piece up. fics% unobserv lecturebot Removing game 5 from observation list. fics% Once you start to observe a particular game or player, the current position will pop up in a chessboard display. As you are an observer, you will not be able to enter new moves. However, you should be able to navigate back and forth in the history of the game. If a new move is made by any party in the game and you are currently displaying the last position in the game, the chessboard display will automatically update to reflect the new position and show the last move in the mode line.  File: chess.info, Node: GNU Free Documentation License, Next: Concept Index, Prev: Internet Chess Servers, Up: Top Appendix A GNU Free Documentation License ***************************************** Version 1.3, 3 November 2008 Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc. Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. 0. PREAMBLE The purpose of this License is to make a manual, textbook, or other functional and useful document “free” in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. 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If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “with...Texts.” line with this: with the Invariant Sections being LIST THEIR TITLES, with the Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST. If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation. If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.  File: chess.info, Node: Concept Index, Next: Function and Variable Index, Prev: GNU Free Documentation License, Up: Top Concept Index ************* [index] * Menu: * acd opcode: Opcode "acd" analysis count depth. (line 6) * acn opcode: Opcode "acn" analysis count nodes. (line 6) * acs opcode: Opcode "acs" analysis count seconds. (line 6) * AI engine: AI. (line 6) * algebraic notation: Algebraic notation. (line 6) * algebraic notation, entering moves with: Entering moves with algebraic notation. (line 6) * algebraic notation, searching moves: Basic operations. (line 15) * am opcode: Opcode "am" avoid move(s). (line 6) * annotations: Annotations. (line 6) * ASCII diagram display: Plain ASCII diagram displays. (line 6) * bishop: Position coordinates. (line 50) * bm opcode: Opcode "bm" best move(s). (line 6) * chess display mode: Chess display mode. (line 6) * Chess ICS mode: Chess ICS Mode. (line 6) * chess opening books modules: Chess Opening Books. (line 6) * chess session: Chess Session. (line 6) * chess-eco module: ECO Classification. (line 6) * chess-file module: chess-file. (line 6) * chess-images module: Graphical displays. (line 6) * chess-none: The Null Engine. (line 6) * chess-scid module: chess-scid. (line 6) * chessboard display: Chessboard displays. (line 6) * collection: Collections. (line 6) * collection database: Opening Databases. (line 6) * Comint mode: Chess ICS Mode. (line 79) * command history: Command History. (line 6) * command history ring: ICS Command Ring. (line 6) * connecting to internet chess server: Connecting to a server. (line 6) * coordinates: Position coordinates. (line 6) * copying command history: ICS History Copying. (line 6) * crafty: Crafty. (line 6) * creating games: Creating games. (line 6) * creating plies: Creating plies. (line 6) * creating positions: Creating positions. (line 6) * creating variations: Creating variations. (line 6) * customize chess-images display: Graphical displays. (line 21) * customize chess-plain display: Plain ASCII diagram displays. (line 51) * customize ics1 display: ICS1 style ASCII displays. (line 32) * database modules: Database Modules. (line 6) * database, modifying: Modifying Databases. (line 6) * database, opening: Opening Databases. (line 6) * display: Chessboard displays. (line 6) * display manipulation functions: Generic display manipulation functions. (line 6) * east: Position coordinates. (line 38) * ECO classification: ECO Classification. (line 6) * engines: Engines. (line 6) * engines, common functions: Common functions. (line 6) * EPD notation: EPD notation. (line 6) * EPD operations: Operations. (line 6) * FEN notation: FEN notation. (line 6) * figurine algebraic notation: Algebraic notation. (line 25) * fruit: Fruit. (line 6) * game: Games. (line 6) * game plies: Game plies. (line 6) * game positions: Game positions. (line 6) * game tags: Game tags. (line 6) * game, creating: Creating games. (line 6) * glaurung: Glaurung. (line 6) * gnuchess: GNU Chess. (line 6) * graphical display: Graphical displays. (line 6) * history copying: ICS History Copying. (line 6) * ICS1 display: ICS1 style ASCII displays. (line 6) * internet chess servers: Internet Chess Servers. (line 6) * library: The chess.el library. (line 6) * long algebraic notation: Algebraic notation. (line 25) * mode, Comint: Chess ICS Mode. (line 79) * mode, ICS: Chess ICS Mode. (line 6) * modifying databases: Modifying Databases. (line 6) * modules: Modules. (line 6) * north: Position coordinates. (line 34) * northeast: Position coordinates. (line 52) * northwest: Position coordinates. (line 64) * null engine: The Null Engine. (line 6) * numeric notation: Algebraic notation. (line 25) * opcodes: Operations. (line 6) * opening database: Opening Databases. (line 6) * PGN mode: PGN mode. (line 6) * PGN notation: PGN notation. (line 6) * phalanx: Phalanx. (line 6) * ply: Plies. (line 6) * ply details: Ply details. (line 6) * ply, creating: Creating plies. (line 6) * polyglot opening book format: Polyglot opening book format support. (line 6) * position: Positions. (line 6) * position coordinates: Position coordinates. (line 6) * position, creating: Creating positions. (line 6) * queen: Position coordinates. (line 32) * queen <1>: Position coordinates. (line 50) * querying databases: Querying Databases. (line 6) * rook: Position coordinates. (line 32) * seek advertisements: The sought game display. (line 6) * seeking opponents: Seeking an opponent for a new game. (line 6) * short algebraic notation: Algebraic notation. (line 25) * sjeng: Sjeng. (line 6) * sought game display: The sought game display. (line 6) * south: Position coordinates. (line 42) * southeast: Position coordinates. (line 56) * southwest: Position coordinates. (line 60) * standard algebraic notation: Algebraic notation. (line 25) * stockfish: Stockfish. (line 6) * tags: Game tags. (line 6) * variation: Variations. (line 6) * variation plies: Variation plies. (line 6) * variation positions: Variation positions. (line 6) * variation, creating: Creating variations. (line 6) * variation, make a move: Making a move in a variation. (line 6) * watching other games: Watching other games. (line 6) * west: Position coordinates. (line 46)  File: chess.info, Node: Function and Variable Index, Next: Key Index, Prev: Concept Index, Up: Top Function and Variable Index *************************** [index] * Menu: * backward-kill-word: Chess ICS Mode. (line 47) * chess: Chess Session. (line 12) * chess-ai-best-move: AI. (line 24) * chess-ai-depth: AI. (line 13) * chess-ai-quiescence-depth: AI. (line 16) * chess-algebraic-regexp: Algebraic notation. (line 50) * chess-algebraic-to-ply: Algebraic notation. (line 14) * chess-coord-to-index: Position coordinates. (line 23) * chess-crafty-path: Crafty. (line 15) * chess-database-filename: Querying Databases. (line 6) * chess-database-modules: Opening Databases. (line 6) * chess-database-open: Opening Databases. (line 10) * chess-database-query: Querying Databases. (line 12) * chess-database-read: Querying Databases. (line 9) * chess-database-read-only-p: Modifying Databases. (line 6) * chess-default-display: Chess Session. (line 31) * chess-default-engine: Chess Session. (line 31) * chess-default-modules: ECO Classification. (line 6) * chess-direction-east: Position coordinates. (line 38) * chess-direction-north: Position coordinates. (line 34) * chess-direction-northeast: Position coordinates. (line 52) * chess-direction-northwest: Position coordinates. (line 64) * chess-direction-south: Position coordinates. (line 42) * chess-direction-southeast: Position coordinates. (line 56) * chess-direction-southwest: Position coordinates. (line 60) * chess-direction-west: Position coordinates. (line 46) * chess-display-active-p: Generic display manipulation functions. (line 12) * chess-display-clear-board: Generic display manipulation functions. (line 17) * chess-display-create: Generic display manipulation functions. (line 6) * chess-display-draw: Basic operations. (line 36) * chess-display-highlight: Generic display manipulation functions. (line 20) * chess-display-highlight-legal: Chess display mode. (line 15) * chess-display-invert: Generic display manipulation functions. (line 28) * chess-display-invert <1>: Basic operations. (line 8) * chess-display-kill-board: Basic operations. (line 43) * chess-display-move: Generic display manipulation functions. (line 31) * chess-display-move-backward: Basic operations. (line 12) * chess-display-move-first: Basic operations. (line 28) * chess-display-move-forward: Basic operations. (line 24) * chess-display-move-last: Basic operations. (line 32) * chess-display-perspective: Generic display manipulation functions. (line 35) * chess-display-position: Generic display manipulation functions. (line 38) * chess-display-quit: Generic display manipulation functions. (line 41) * chess-display-quit <1>: Basic operations. (line 58) * chess-display-resign: Basic operations. (line 39) * chess-display-search-backward: Basic operations. (line 16) * chess-display-search-forward: Basic operations. (line 20) * chess-display-select-piece: Selecting pieces with the keyboard. (line 12) * chess-display-select-piece <1>: Selecting pieces with the mouse. (line 13) * chess-display-set-game: Generic display manipulation functions. (line 44) * chess-display-set-perspective: Generic display manipulation functions. (line 50) * chess-display-set-position: Generic display manipulation functions. (line 53) * chess-display-set-variation: Generic display manipulation functions. (line 57) * chess-display-update: Generic display manipulation functions. (line 65) * chess-display-yank-board: Basic operations. (line 50) * chess-engine-command: Common functions. (line 18) * chess-engine-create: Common functions. (line 6) * chess-engine-position: Common functions. (line 15) * chess-engine-send: Common functions. (line 21) * chess-engine-set-option: Common functions. (line 11) * chess-epd-read-file: EPD notation. (line 29) * chess-epd-to-pos: EPD notation. (line 20) * chess-fen-to-pos: FEN notation. (line 32) * chess-fischer-random-position: Creating positions. (line 19) * chess-fruit-path: Fruit. (line 18) * chess-game-add-hook: Games. (line 17) * chess-game-add-ply: Games. (line 20) * chess-game-create: Creating games. (line 6) * chess-game-del-tag: Game tags. (line 19) * chess-game-hooks: Games. (line 23) * chess-game-index: Game positions. (line 9) * chess-game-move: Making a move. (line 6) * chess-game-plies: Games. (line 26) * chess-game-ply: Game plies. (line 6) * chess-game-pos: Game positions. (line 6) * chess-game-remove-hook: Games. (line 29) * chess-game-run-hooks: Games. (line 33) * chess-game-seq: Game positions. (line 12) * chess-game-set-hooks: Games. (line 36) * chess-game-set-plies: Games. (line 39) * chess-game-set-tag: Game tags. (line 16) * chess-game-set-tags: Game tags. (line 9) * chess-game-side-to-move: Game positions. (line 15) * chess-game-tag: Game tags. (line 13) * chess-game-tags: Game tags. (line 6) * chess-game-to-pgn: PGN notation. (line 10) * chess-glaurung-path: Glaurung. (line 12) * chess-gnuchess-path: GNU Chess. (line 16) * chess-ics: Connecting to a server. (line 8) * chess-ics-ads-mode: The sought game display. (line 13) * chess-ics-server-list: Internet Chess Servers. (line 17) * chess-ics1-separate-frame: ICS1 style ASCII displays. (line 29) * chess-images-directory: Graphical displays. (line 9) * chess-images-separate-frame: Graphical displays. (line 18) * chess-index-file: Position coordinates. (line 14) * chess-index-rank: Position coordinates. (line 11) * chess-index-to-coord: Position coordinates. (line 26) * chess-input-shortcut: Entering moves with algebraic notation. (line 15) * chess-input-shortcut-delete: Entering moves with algebraic notation. (line 27) * chess-legal-plies: Creating plies. (line 16) * chess-next-index: Position coordinates. (line 68) * chess-pgn-insert-plies: PGN notation. (line 15) * chess-pgn-to-game: PGN notation. (line 6) * chess-pgn-visualize: PGN mode. (line 6) * chess-phalanx-path: Phalanx. (line 12) * chess-plain-black-square-char: Plain ASCII diagram displays. (line 31) * chess-plain-border-style: Plain ASCII diagram displays. (line 26) * chess-plain-piece-chars: Plain ASCII diagram displays. (line 37) * chess-plain-separate-frame: Plain ASCII diagram displays. (line 23) * chess-plain-spacing: Plain ASCII diagram displays. (line 48) * chess-plain-upcase-indicates: Plain ASCII diagram displays. (line 40) * chess-plain-white-square-char: Plain ASCII diagram displays. (line 34) * chess-ply-changes: Ply details. (line 12) * chess-ply-create: Creating plies. (line 6) * chess-ply-final-p: The "next" position. (line 9) * chess-ply-keyword: Polyglot opening book format support. (line 27) * chess-ply-next-pos: The "next" position. (line 6) * chess-ply-pos: Ply details. (line 6) * chess-ply-set-changes: Ply details. (line 19) * chess-ply-set-pos: Ply details. (line 9) * chess-ply-source: Ply details. (line 23) * chess-ply-target: Ply details. (line 26) * chess-ply-to-algebraic: Algebraic notation. (line 25) * chess-polyglot-book: Polyglot opening book format support. (line 15) * chess-polyglot-book-file: Polyglot opening book format support. (line 12) * chess-polyglot-book-open: Polyglot opening book format support. (line 22) * chess-polyglot-book-plies: Polyglot opening book format support. (line 27) * chess-polyglot-book-ply: Polyglot opening book format support. (line 34) * chess-polyglot-book-strength: Polyglot opening book format support. (line 34) * chess-pos-add-annotation: Annotations. (line 9) * chess-pos-always-white: Position details. (line 102) * chess-pos-annotations: Annotations. (line 6) * chess-pos-can-castle: Position details. (line 53) * chess-pos-copy: Creating positions. (line 11) * chess-pos-create: Creating positions. (line 6) * chess-pos-en-passant: Position details. (line 68) * chess-pos-move: Position details. (line 107) * chess-pos-passed-pawns: Position details. (line 92) * chess-pos-piece: Position details. (line 9) * chess-pos-piece-p: Position details. (line 12) * chess-pos-search: Position details. (line 22) * chess-pos-search*: Position details. (line 27) * chess-pos-set-can-castle: Position details. (line 58) * chess-pos-set-en-passant: Position details. (line 72) * chess-pos-set-piece: Position details. (line 17) * chess-pos-set-side-to-move: Position details. (line 89) * chess-pos-set-status: Position details. (line 81) * chess-pos-side-to-move: Position details. (line 86) * chess-pos-status: Position details. (line 76) * chess-pos-to-epd: EPD notation. (line 25) * chess-pos-to-fen: FEN notation. (line 35) * chess-rf-to-index: Position coordinates. (line 17) * chess-search-position: Position details. (line 35) * chess-sjeng-path: Sjeng. (line 14) * chess-starting-position: Creating positions. (line 16) * chess-starting-position <1>: FEN notation. (line 41) * chess-stockfish-path: Stockfish. (line 15) * chess-var-add-ply: Making a move in a variation. (line 13) * chess-var-create: Creating variations. (line 6) * chess-var-index: Variation positions. (line 9) * chess-var-move: Making a move in a variation. (line 6) * chess-var-plies: Variation plies. (line 9) * chess-var-ply: Variation plies. (line 6) * chess-var-pos: Variation positions. (line 6) * chess-var-seq: Variation positions. (line 12) * chess-var-side-to-move: Variation positions. (line 15) * chess-var-to-algebraic: Variation plies. (line 12) * comint-accumulate: Chess ICS Mode. (line 34) * comint-bol-or-process-mark: Chess ICS Mode. (line 25) * comint-buffer-maximum-size: Chess ICS Mode. (line 71) * comint-copy-old-input: ICS History Copying. (line 12) * comint-delchar-or-maybe-eof: Chess ICS Mode. (line 18) * comint-delete-output: Chess ICS Mode. (line 50) * comint-dynamic-list-input-ring: ICS Command Ring. (line 27) * comint-get-next-from-history: ICS Command Ring. (line 19) * comint-history-isearch-backward-regexp: ICS Command Ring. (line 14) * comint-input-previous-argument: ICS Command Ring. (line 23) * comint-kill-input: Chess ICS Mode. (line 42) * comint-next-input: ICS Command Ring. (line 10) * comint-next-prompt: ICS History Copying. (line 9) * comint-previous-input: ICS Command Ring. (line 6) * comint-previous-prompt: ICS History Copying. (line 6) * comint-send-input: Chess ICS Mode. (line 11) * comint-show-maximum-output: Chess ICS Mode. (line 67) * comint-show-output: Chess ICS Mode. (line 62) * comint-truncate-buffer: Chess ICS Mode. (line 71) * comint-write-output: Chess ICS Mode. (line 55)  File: chess.info, Node: Key Index, Prev: Function and Variable Index, Up: Top Key Index ********* [index] * Menu: * ,: Basic operations. (line 11) * .: Basic operations. (line 23) * 1: Entering moves with algebraic notation. (line 6) * 2: Entering moves with algebraic notation. (line 6) * 3: Entering moves with algebraic notation. (line 6) * 4: Entering moves with algebraic notation. (line 6) * 5: Entering moves with algebraic notation. (line 6) * 6: Entering moves with algebraic notation. (line 6) * 7: Entering moves with algebraic notation. (line 6) * 8: Entering moves with algebraic notation. (line 6) * <: Basic operations. (line 27) * =: Entering moves with algebraic notation. (line 6) * >: Basic operations. (line 31) * a: Entering moves with algebraic notation. (line 6) * b: Entering moves with algebraic notation. (line 6) * B: Entering moves with algebraic notation. (line 6) * backspace: Entering moves with algebraic notation. (line 26) * c: Entering moves with algebraic notation. (line 6) * C-c .: ICS Command Ring. (line 23) * C-c C-a: Chess ICS Mode. (line 25) * C-c C-d: Basic operations. (line 35) * C-c C-e: Chess ICS Mode. (line 67) * C-c C-l: ICS Command Ring. (line 27) * C-c C-n: ICS History Copying. (line 9) * C-c C-o: Chess ICS Mode. (line 50) * C-c C-p: ICS History Copying. (line 6) * C-c C-r: Basic operations. (line 38) * C-c C-r <1>: Chess ICS Mode. (line 62) * C-c C-s: Chess ICS Mode. (line 55) * C-c C-u: Chess ICS Mode. (line 42) * C-c C-w: Chess ICS Mode. (line 47) * C-c C-x: ICS Command Ring. (line 19) * C-c RET: ICS History Copying. (line 12) * C-c SPC: Chess ICS Mode. (line 34) * C-d: Chess ICS Mode. (line 18) * C-i: Basic operations. (line 6) * C-M-l: Chess ICS Mode. (line 62) * C-r: Basic operations. (line 15) * C-s: Basic operations. (line 19) * C-u M-w: Basic operations. (line 41) * C-u M-x chess RET: Chess Session. (line 35) * C-u M-x chess RET ai RET: AI. (line 10) * C-u M-x chess RET crafty RET: Crafty. (line 18) * C-u M-x chess RET fruit RET: Fruit. (line 21) * C-u M-x chess RET glaurung RET: Glaurung. (line 15) * C-u M-x chess RET gnuchess RET: GNU Chess. (line 19) * C-u M-x chess RET none RET: The Null Engine. (line 13) * C-u M-x chess RET phalanx RET: Phalanx. (line 15) * C-u M-x chess RET sjeng RET: Sjeng. (line 17) * C-u M-x chess RET stockfish RET: Stockfish. (line 18) * C-y: Basic operations. (line 49) * d: Entering moves with algebraic notation. (line 6) * down-mouse-1: Selecting pieces with the mouse. (line 9) * down-mouse-2: Selecting pieces with the mouse. (line 9) * drag-mouse-1: Selecting pieces with the mouse. (line 9) * drag-mouse-2: Selecting pieces with the mouse. (line 9) * e: Entering moves with algebraic notation. (line 6) * f: Entering moves with algebraic notation. (line 6) * g: Entering moves with algebraic notation. (line 6) * h: Entering moves with algebraic notation. (line 6) * K: Entering moves with algebraic notation. (line 6) * M-n: ICS Command Ring. (line 10) * M-p: ICS Command Ring. (line 6) * M-r: ICS Command Ring. (line 14) * M-w: Basic operations. (line 41) * M-x chess RET: Chess Session. (line 31) * M-x customize-group RET chess-ics1 RET: ICS1 style ASCII displays. (line 32) * M-x customize-group RET chess-images RET: Graphical displays. (line 21) * M-x customize-group RET chess-plain RET: Plain ASCII diagram displays. (line 51) * N: Entering moves with algebraic notation. (line 6) * Q: Entering moves with algebraic notation. (line 6) * R: Entering moves with algebraic notation. (line 6) * RET: Selecting pieces with the keyboard. (line 11) * RET <1>: Chess ICS Mode. (line 11) * RET <2>: The sought game display. (line 24) * TAB: Basic operations. (line 6) * X: Basic operations. (line 57) * x: Entering moves with algebraic notation. (line 6)  Tag Table: Node: Top1474 Node: The chess.el library2563 Node: Positions3072 Node: Creating positions4069 Node: Position coordinates4828 Node: Position details7423 Node: Annotations12485 Node: FEN notation12827 Node: EPD notation14679 Node: Operations16195 Node: Opcode "acd" analysis count depth17157 Node: Opcode "acn" analysis count nodes17542 Node: Opcode "acs" analysis count seconds18076 Node: Opcode "am" avoid move(s)18605 Node: Opcode "bm" best move(s)19054 Node: Plies19457 Node: Creating plies20616 Node: Ply details22341 Node: The "next" position23486 Node: Algebraic notation23854 Node: Variations25712 Node: Creating variations26819 Node: Variation positions27109 Node: Variation plies27765 Node: Making a move in a variation28252 Node: Games28841 Node: Creating games30457 Node: Game tags30836 Node: Game positions31462 Node: Game plies32136 Node: Making a move32411 Node: PGN notation32848 Node: PGN mode33600 Node: Collections33840 Node: Opening Databases34629 Node: Querying Databases35104 Node: Modifying Databases35778 Node: Finalizing Databases36056 Node: Database Modules36231 Node: chess-file36489 Node: chess-scid37114 Node: Chess Opening Books37359 Node: ECO Classification37678 Node: Polyglot opening book format support38094 Node: Modules39988 Node: Chessboard displays46785 Node: Generic display manipulation functions47419 Node: Chess display mode50231 Node: Basic operations51173 Node: Selecting pieces with the keyboard52975 Node: Selecting pieces with the mouse53567 Node: Entering moves with algebraic notation54132 Node: Plain ASCII diagram displays55152 Node: ICS1 style ASCII displays57051 Node: Graphical displays58420 Node: Engines59282 Node: Common functions59806 Node: The Null Engine60857 Node: AI61400 Node: Crafty62378 Node: Fruit63174 Node: Glaurung64079 Node: GNU Chess64728 Node: Phalanx65662 Node: Sjeng66303 Node: Stockfish67051 Node: Chess Session67877 Node: Internet Chess Servers69650 Node: Connecting to a server70824 Node: Chess ICS Mode71349 Node: Command History74874 Node: ICS Command Ring75495 Node: ICS History Copying78878 Node: Seeking an opponent for a new game80396 Node: The sought game display81050 Node: Watching other games82086 Node: GNU Free Documentation License83569 Node: Concept Index108936 Node: Function and Variable Index118294 Node: Key Index135915  End Tag Table  Local Variables: coding: utf-8 End: