[bitboard] Implement a Square type; fix all the build issues after adding a mod line to lib.rs

bitboard/src/bitboard.rs

@@ -1,4 +1,4 @@
 // Eryn Wells <eryn@erynwells.me>
 
 #[derive(Clone, Copy, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)]
-pub struct BitBoard(u64);
+pub struct BitBoard(pub u64);

bitboard/src/lib.rs

@@ -1,10 +1,3 @@
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
-    }
-}
+mod bitboard;
+mod position;
+mod square;

bitboard/src/position.rs

@@ -1,17 +1,20 @@
 // Eryn Wells <eryn@erynwells.me>
 
+use crate::bitboard::BitBoard;
+use std::fmt;
+
 mod color {
-    const WHITE = 0;
-    const BLACK = 1;
+    const WHITE: u8 = 0;
+    const BLACK: u8 = 1;
 }
 
 mod piece {
-    const PAWN = 0;
-    const KNIGHT = 1;
-    const BISHOP = 2;
-    const ROOK = 3;
-    const QUEEN = 4;
-    const KING = 5;
+    const PAWN: u8 = 0;
+    const KNIGHT: u8 = 1;
+    const BISHOP: u8 = 2;
+    const ROOK: u8 = 3;
+    const QUEEN: u8 = 4;
+    const KING: u8 = 5;
 }
 
 #[derive(Clone, Debug, Eq, Hash, PartialEq)]
@@ -24,10 +27,64 @@ pub struct Position {
 }
 
 impl Position {
-    static fn empty() -> Position {
+    fn empty() -> Position {
         Position {
-            pieces_per_color = [],
-            pieces_per_type = [],
+            pieces_per_color: [BitBoard(0), BitBoard(0)],
+            pieces_per_type: [
+                [
+                    BitBoard(0),
+                    BitBoard(0),
+                    BitBoard(0),
+                    BitBoard(0),
+                    BitBoard(0),
+                    BitBoard(0),
+                ],
+                [
+                    BitBoard(0),
+                    BitBoard(0),
+                    BitBoard(0),
+                    BitBoard(0),
+                    BitBoard(0),
+                    BitBoard(0),
+                ],
+            ],
         }
     }
+
+    /// Return a starting position.
+    fn starting() -> Position {
+        let white_pieces = [
+            BitBoard(0x00FF000000000000),
+            BitBoard(0x4200000000000000),
+            BitBoard(0x2400000000000000),
+            BitBoard(0x8100000000000000),
+            BitBoard(0x1000000000000000),
+            BitBoard(0x8000000000000000),
+        ];
+
+        let black_pieces = [
+            BitBoard(0xFF00),
+            BitBoard(0x0042),
+            BitBoard(0x0024),
+            BitBoard(0x0081),
+            BitBoard(0x0010),
+            BitBoard(0x0080),
+        ];
+
+        Position {
+            pieces_per_color: [
+                BitBoard(white_pieces.iter().map(|bb| bb.0).fold(0, |a, b| a | b)),
+                BitBoard(black_pieces.iter().map(|bb| bb.0).fold(0, |a, b| a | b)),
+            ],
+            pieces_per_type: [white_pieces, black_pieces],
+        }
+    }
+
+    fn piece_at_square(&self, sq: &str) {}
+}
+
+impl fmt::Display for Position {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "abcdefg")
+    }
 }

bitboard/src/square.rs

@@ -0,0 +1,103 @@
+// Eryn Wells <eryn@erynwells.me>
+
+use std::str::FromStr;
+
+#[derive(Debug)]
+struct ParseSquareError;
+
+#[derive(Debug)]
+struct SquareIndexOutOfBoundsError;
+
+#[derive(Debug, Eq, PartialEq)]
+struct Square {
+    rank: u8,
+    file: u8,
+}
+
+impl Square {
+    fn from_index(index: u8) -> Result<Square, SquareIndexOutOfBoundsError> {
+        if index >= 64 {
+            return Err(SquareIndexOutOfBoundsError);
+        }
+
+        Ok(Square {
+            rank: index / 8,
+            file: index % 8,
+        })
+    }
+
+    fn from_algebraic_string(s: &str) -> Result<Square, ParseSquareError> {
+        s.parse()
+    }
+
+    fn rank_index(&self) -> usize {
+        self.rank.into()
+    }
+
+    fn file_index(&self) -> usize {
+        self.file.into()
+    }
+}
+
+impl FromStr for Square {
+    type Err = ParseSquareError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if !s.is_ascii() || s.len() != 2 {
+            return Err(ParseSquareError);
+        }
+
+        let chars: Vec<char> = s.chars().collect();
+        let rank_char = chars[0].to_ascii_lowercase();
+        if !rank_char.is_ascii_lowercase() {
+            return Err(ParseSquareError);
+        }
+
+        let rank = (rank_char as u8) - ('a' as u8) + 1;
+        if rank < 1 || rank > 8 {
+            return Err(ParseSquareError);
+        }
+
+        let file = u8::try_from(chars[1].to_digit(10).ok_or(ParseSquareError)?)
+            .map_err(|_| ParseSquareError)?;
+
+        Ok(Square {
+            rank: rank - 1,
+            file: file - 1,
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn indexes() {
+        let sq1 = Square::from_algebraic_string("c5").expect("Failed to parse 'c5' square");
+        assert_eq!(sq1.rank_index(), 2, "Rank doesn't match");
+        assert_eq!(sq1.file_index(), 4, "File doesn't match");
+
+        let sq2 = Square::from_algebraic_string("b2").expect("Failed to parse 'b2' square");
+        assert_eq!(sq2.rank_index(), 1, "Rank doesn't match");
+        assert_eq!(sq2.file_index(), 1, "File doesn't match");
+    }
+
+    #[test]
+    fn parse_good_input() {
+        let sq1 = Square::from_algebraic_string("a4").expect("Failed to parse 'a4' square");
+        assert_eq!(sq1.rank, 0);
+        assert_eq!(sq1.file, 3);
+
+        let sq2 = Square::from_algebraic_string("B8").expect("Failed to parse 'B8' square");
+        assert_eq!(sq2.rank, 1);
+        assert_eq!(sq2.file, 7);
+    }
+
+    #[test]
+    fn from_index() {
+        let sq1 = Square::from_index(4).expect("Unable to get Square from index");
+        assert_eq!(sq1.rank, 0);
+        assert_eq!(sq1.file, 4);
+    }
+}