diff --git a/src/position.rs b/src/position.rs
index c7bffc4..22472b4 100644
--- a/src/position.rs
+++ b/src/position.rs
@@ -60,6 +60,26 @@ pub struct Position(Setup);
 
 pub(crate) const MAX_LEGAL_MOVES: usize = 218;
 
+const PAWN: u8 = Role::Pawn as u8;
+const KNIGHT: u8 = Role::Knight as u8;
+const BISHOP: u8 = Role::Bishop as u8;
+const ROOK: u8 = Role::Rook as u8;
+const QUEEN: u8 = Role::Queen as u8;
+const KING: u8 = Role::King as u8;
+
+macro_rules! map_role {
+    ($f:ident, $role:ident, $($x:expr),+) => (
+        match $role {
+            Role::Pawn => $f::<PAWN>($($x),+),
+            Role::Knight => $f::<KNIGHT>($($x),+),
+            Role::Bishop => $f::<BISHOP>($($x),+),
+            Role::Rook => $f::<ROOK>($($x),+),
+            Role::Queen => $f::<QUEEN>($($x),+),
+            Role::King => $f::<KING>($($x),+),
+        }
+    )
+}
+
 impl Position {
     /// Returns the initial position of a chess game.
     ///
@@ -366,14 +386,7 @@ impl Position {
         } else {
             role
         };
-        match role {
-            Role::Pawn => aux::<1>(self, promotion, from, to),
-            Role::Knight => aux::<2>(self, promotion, from, to),
-            Role::Bishop => aux::<3>(self, promotion, from, to),
-            Role::Rook => aux::<4>(self, promotion, from, to),
-            Role::Queen => aux::<5>(self, promotion, from, to),
-            Role::King => aux::<6>(self, promotion, from, to),
-        }
+        map_role!(aux, role, self, promotion, from, to)
     }
 
     pub(crate) fn move_from_san<'l>(&'l self, san: &San) -> Result<Move<'l>, InvalidSan> {
@@ -482,14 +495,7 @@ impl Position {
                 },
             }
         }
-        match role {
-            Role::Pawn => aux::<1>(self, promotion, from, to),
-            Role::Knight => aux::<2>(self, promotion, from, to),
-            Role::Bishop => aux::<3>(self, promotion, from, to),
-            Role::Rook => aux::<4>(self, promotion, from, to),
-            Role::Queen => aux::<5>(self, promotion, from, to),
-            Role::King => aux::<6>(self, promotion, from, to),
-        }
+        map_role!(aux, role, self, promotion, from, to)
     }
 }