--- a/src/chess/rules.h Mon Aug 24 16:13:51 2026 +0200
+++ b/src/chess/rules.h Tue Aug 25 18:35:18 2026 +0200
@@ -49,11 +49,27 @@
#define INVALID_CHECKMATE 11
#define RULES_VIOLATED 32
+#if __STDC_VERSION__ < 202310L
+/* since #warning is also a C23 feature, the only hope is this: */
+#pragma GCC warning "Type safety for enums is only available since C23"
+#define enum_uint8_t(name) enum e##name
+#define typedef_enum_uint8_t(name) typedef uint8_t name
+#else
+#define enum_uint8_t(name) enum e##name : uint8_t
+#define typedef_enum_uint8_t(name) typedef enum e##name name
+#endif
+
#define ENPASSANT_THREAT 0x40u
-#define WHITE 0x10u
-#define BLACK 0x20u
-#define opponent_color(color) ((color)==WHITE?BLACK:WHITE)
+enum_uint8_t(Color) {
+ WHITE = 0x10u,
+ BLACK = 0x20u,
+};
+typedef_enum_uint8_t(Color);
+
+static inline Color opponent_color(Color color) {
+ return color == WHITE ? BLACK : WHITE;
+}
#define PIECE_MASK 0x0Fu
#define COLOR_MASK 0x30u
@@ -65,25 +81,36 @@
#define QUEEN 0x05u
#define KING 0x06u
-#define WPAWN (WHITE|PAWN)
-#define WROOK (WHITE|ROOK)
-#define WKNIGHT (WHITE|KNIGHT)
-#define WBISHOP (WHITE|BISHOP)
-#define WQUEEN (WHITE|QUEEN)
-#define WKING (WHITE|KING)
-#define BPAWN (BLACK|PAWN)
-#define BROOK (BLACK|ROOK)
-#define BKNIGHT (BLACK|KNIGHT)
-#define BBISHOP (BLACK|BISHOP)
-#define BQUEEN (BLACK|QUEEN)
-#define BKING (BLACK|KING)
+enum_uint8_t(Piece) {
+ WPAWN = WHITE|PAWN,
+ WROOK = WHITE|ROOK,
+ WKNIGHT = WHITE|KNIGHT,
+ WBISHOP = WHITE|BISHOP,
+ WQUEEN = WHITE|QUEEN,
+ WKING = WHITE|KING,
+ BPAWN = BLACK|PAWN,
+ BROOK = BLACK|ROOK,
+ BKNIGHT = BLACK|KNIGHT,
+ BBISHOP = BLACK|BISHOP,
+ BQUEEN = BLACK|QUEEN,
+ BKING = BLACK|KING,
+};
+typedef_enum_uint8_t(Piece);
+
+#define POS_UNSPECIFIED 255u
+enum_uint8_t(Row) {
+ RANK_1 = 0, RANK_2, RANK_3, RANK_4, RANK_5, RANK_6, RANK_7, RANK_8,
+ RANK_UNSPECIFIED = POS_UNSPECIFIED
+};
+typedef_enum_uint8_t(Row);
+
+enum_uint8_t(File) {
+ FILE_A = 0, FILE_B, FILE_C, FILE_D, FILE_E, FILE_F, FILE_G, FILE_H,
+ FILE_UNSPECIFIED = POS_UNSPECIFIED
+};
+typedef_enum_uint8_t(File);
typedef uint8_t Board[8][8];
-typedef uint8_t BoardIndex;
-typedef BoardIndex Row;
-typedef BoardIndex File;
-typedef uint8_t Piece;
-typedef uint8_t Color;
struct movetimeval {
uint64_t sec;
@@ -154,31 +181,26 @@
bool review;
} GameState;
-#define piece_type(piece) ((piece)&PIECE_MASK)
-#define piece_color(piece) ((piece)&COLOR_MASK)
-#define mkpiece(type,color) ((type)|(color))
+#define piece_type(piece) ((uint8_t)(piece)&PIECE_MASK)
+#define piece_color(piece) ((uint8_t)(piece)&COLOR_MASK)
+#define mkpiece(type,color) (Piece)((type)|(color))
-#define POS_UNSPECIFIED UINT8_MAX
#define mdst(m) (m)->torow, (m)->tofile
#define msrc(m) (m)->fromrow, (m)->fromfile
/** Checks if the index is specified and valid. */
-#define isidx(idx) ((BoardIndex)(idx) < 8)
+static inline bool isidx(uint8_t idx) {return idx < 8;}
/** Checks if the index is unspecified or valid. */
-#define isidxr(idx) ((idx) == POS_UNSPECIFIED || (BoardIndex)(idx) < 8)
-
-#define isfile(file) (file >= 'a' && file <= 'h')
-#define isrow(row) (row >= '1' && row <= '8')
+static inline bool isidxr(uint8_t idx) {return idx==POS_UNSPECIFIED || idx<8;}
-#define rowidx(row) (row-'1')
-#define fileidx(file) (file-'a')
+static inline bool isfile(char file) {return file >= 'a' && file <= 'h';}
+static inline bool isrow(char row) {return row >= '1' && row <= '8';}
-#define rowchr(row) (row+'1')
-#define filechr(file) (file+'a')
+static inline Row rowidx(char row) {return row-'1';}
+static inline File fileidx(char file) {return file-'a';}
-/* secure versions - use, if index is not checked with isidx() */
-#define fileidx_s(c) (isfile(c)?fileidx(c):POS_UNSPECIFIED)
-#define rowidx_s(c) (isrow(c)?rowidx(c):POS_UNSPECIFIED)
+static inline char rowchr(Row row) {return (char)row+'1';}
+static inline char filechr(File file) {return (char)file+'a';}
static inline void enpassant_threat_add(GameState *gamestate,