Implement PeSTO eval

src/board/board.rs

@@ -204,6 +204,17 @@ impl PieceType {
     pub const fn idx(self) -> usize {
         self as usize
     }
+
+    pub const fn score(self) -> i32 {
+        match self {
+            Self::Pawn => 100,
+            Self::Knight => 320,
+            Self::Bishop => 330,
+            Self::Rook => 500,
+            Self::Queen => 900,
+            Self::King => 20000,
+        }
+    }
 }
 use std::ops::{Index, IndexMut};