Adapts the code so that it can compile with TinyGo.

api/api.go

@@ -1,21 +1,20 @@
 package api
 
-import (
-	"fmt"
-)
+import "errors"
 
 type API struct{}
 
 func New() API { return API{} }
 
 var (
-	errInvalidInputGame                    = fmt.Errorf("invalid input game: please supply a valid fenString or a board")
-	errAlgebraicSquareInvalidOrOutOfBounds = fmt.Errorf("invalid algebraic square: empty or out of bounds")
-	errInvalidPieceTypeName                = fmt.Errorf("invalid piece type name: please use one of {Queen|King|Bishop|Knight|Rook|Pawn} or empty string")
-	errInvalidActionForGivenGame           = fmt.Errorf("the specified action is invalid for the specified game")
+	errInvalidInputGame                    = errors.New("invalid input game: please supply a valid fenString or a board")
+	errAlgebraicSquareInvalidOrOutOfBounds = errors.New("invalid algebraic square: empty or out of bounds")
+	errInvalidPieceTypeName                = errors.New("invalid piece type name: please use one of {Queen|King|Bishop|Knight|Rook|Pawn} or empty string")
+	errInvalidActionForGivenGame           = errors.New("the specified action is invalid for the specified game")
 )
 
 func (a API) DefaultGame() OutputGame {
+	var defaultGame, _ = newGameFromFEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1")
 	return mapGameToOutputGame(defaultGame)
 }
 

api/api_utils.go

@@ -11,6 +11,7 @@ func (a API) parseGame(g InputGame) (game, error) {
 	)
 	switch {
 	case g.DefaultGame:
+		var defaultGame, _ = newGameFromFEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1")
 		parsedGame = defaultGame
 	case g.FENString != "":
 		parsedGame, err = newGameFromFEN(g.FENString)

api/board.go

@@ -1,6 +1,7 @@
 package api
 
 import (
+	"errors"
 	"fmt"
 	"strings"
 )
@@ -18,21 +19,21 @@ type board struct {
 }
 
 var (
-	errBoardInvalidEnPassantTargetSquare   = fmt.Errorf("enPassantTargetSquare must be either empty string or valid algebraic notation square e.g. d6")
-	errBoardTurnMustBeBlackOrWhite         = fmt.Errorf("turn must be either Black or White")
-	errBoardDuplicateKing                  = fmt.Errorf("board has two kings of the same color")
-	errBoardKingMissing                    = fmt.Errorf("board is missing one of the kings")
-	errBoardDimensionsWrong                = fmt.Errorf("board dimensions are wrong; should be 8x8")
-	errBoardImpossibleBlackCastle          = fmt.Errorf("impossible for black to castle since king has moved")
-	errBoardImpossibleBlackQueensideCastle = fmt.Errorf("impossible for black to queenside castle since rook has moved")
-	errBoardImpossibleBlackKingsideCastle  = fmt.Errorf("impossible for black to kingside castle since rook has moved")
-	errBoardImpossibleWhiteCastle          = fmt.Errorf("impossible for white to castle since king has moved")
-	errBoardImpossibleWhiteQueensideCastle = fmt.Errorf("impossible for white to queenside castle since rook has moved")
-	errBoardImpossibleWhiteKingsideCastle  = fmt.Errorf("impossible for white to kingside castle since rook has moved")
-	errBoardImpossibleEnPassant            = fmt.Errorf("impossible en passant target square, since there's no pawn of the right color next to it")
-	errBoardPawnInImpossibleRank           = fmt.Errorf("impossible rank for pawn")
-	errBoardBlackHasMoreThan16Pieces       = fmt.Errorf("black has more than 16 pieces")
-	errBoardWhiteHasMoreThan16Pieces       = fmt.Errorf("white has more than 16 pieces")
+	errBoardInvalidEnPassantTargetSquare   = errors.New("enPassantTargetSquare must be either empty string or valid algebraic notation square e.g. d6")
+	errBoardTurnMustBeBlackOrWhite         = errors.New("turn must be either Black or White")
+	errBoardDuplicateKing                  = errors.New("board has two kings of the same color")
+	errBoardKingMissing                    = errors.New("board is missing one of the kings")
+	errBoardDimensionsWrong                = errors.New("board dimensions are wrong; should be 8x8")
+	errBoardImpossibleBlackCastle          = errors.New("impossible for black to castle since king has moved")
+	errBoardImpossibleBlackQueensideCastle = errors.New("impossible for black to queenside castle since rook has moved")
+	errBoardImpossibleBlackKingsideCastle  = errors.New("impossible for black to kingside castle since rook has moved")
+	errBoardImpossibleWhiteCastle          = errors.New("impossible for white to castle since king has moved")
+	errBoardImpossibleWhiteQueensideCastle = errors.New("impossible for white to queenside castle since rook has moved")
+	errBoardImpossibleWhiteKingsideCastle  = errors.New("impossible for white to kingside castle since rook has moved")
+	errBoardImpossibleEnPassant            = errors.New("impossible en passant target square, since there's no pawn of the right color next to it")
+	errBoardPawnInImpossibleRank           = errors.New("impossible rank for pawn")
+	errBoardBlackHasMoreThan16Pieces       = errors.New("black has more than 16 pieces")
+	errBoardWhiteHasMoreThan16Pieces       = errors.New("white has more than 16 pieces")
 	// TODO check if King is in checkmate that couldn't have been reached
 	// TODO don't allow more than 8 pawns of any color
 	// TODO check if both are in check