! takes values from a hashtable and matches them against tuple's slots names, replacing the slots' values with the corresponding ones (unless the value is f).

: slot-names ( mirror -- seq )        
    >alist [ first ] map ;
        
: slot-values-from-hash ( hash seq -- slot-value-pairs )
    [ [ swap at ] keep swap 2array ] with map
    [ second ] filter ;
        
: set-mirror-slots ( mirror value-pairs -- mirror' ) 
    over '[ first2 swap _ set-at ] each ;
        
: values-to-slots ( hash mirror -- mirror' )
    tuck slot-names slot-values-from-hash set-mirror-slots ;
    
: hash>slots ( hash tuple -- tuple' )
    <mirror> values-to-slots object>> ;