chess960 buddy

extra/chess960/chess960.factor

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+USING: math.ranges kernel random sequences arrays combinators ;
+IN: chess960
+
+SYMBOLS: pawn rook knight bishop queen king ;
+
+: all-positions ( -- range ) 0 8 [a,b) ;
+
+: black-bishop-positions ( -- range ) 0 6 2 <range> ;
+: white-bishop-positions ( -- range ) 1 7 2 <range> ;
+
+: frisk ( position positions -- position positions' )
+    [ drop ] [ remove ] 2bi ;
+
+: white-bishop ( positions -- position positions' )
+    [ white-bishop-positions random ] dip frisk ;
+: black-bishop ( positions -- position positions' )
+    [ black-bishop-positions random ] dip frisk ;
+
+: random-position ( positions -- position positions' )
+    [ random ] keep frisk ;
+
+: make-position ( white-bishop black-bishop knight knight queen {r,k,r} -- position )
+    first3
+    8 f <array> {
+        [ [ rook ] 2dip set-nth ]
+        [ [ king ] 2dip set-nth ]
+        [ [ rook ] 2dip set-nth ]
+        [ [ queen ] 2dip set-nth ]
+        [ [ knight ] 2dip set-nth ]
+        [ [ knight ] 2dip set-nth ]
+        [ [ bishop ] 2dip set-nth ]
+        [ [ bishop ] 2dip set-nth ]
+        [ ]
+    } cleave ;
+
+: chess960-position ( -- position )
+    all-positions
+    white-bishop
+    black-bishop
+    random-position
+    random-position
+    random-position
+    make-position ;