Morse Code in Factor

I am getting the hang of this. This is a string>morse code and morse code>string converter as per this programming praxis problem. My implementation ignores extra whitespace in the morse code stream.

USING: ascii lists sequences regexp ;

: ch>morse ch>upper ( char -- morse-str )
         { { CHAR: 0 [ "— — — — —" ] }
           { CHAR: 1 [ "• — — — —" ] }
           { CHAR: 2 [ "• • — — —" ] }
           { CHAR: 3 [ "• • • — —" ] }
           { CHAR: 4 [ "• • • • —" ] }
           { CHAR: 5 [ "• • • • •" ] }
           { CHAR: 6 [ "— • • • •" ] }
           { CHAR: 7 [ "— — • • •" ] }
           { CHAR: 8 [ "— — — • •" ] }
           { CHAR: 9 [ "— — — — •" ] }
           { CHAR: A [ "• —" ] } 
           { CHAR: B [ "— • • •" ] }
           { CHAR: C [ "— • — •" ] } 
           { CHAR: D [ "— • •" ] } 
           { CHAR: E [ "• • •" ] }
           { CHAR: F [ "• • — •" ] }
           { CHAR: G [ "— — •" ] }
           { CHAR: H [ "• • • •" ] } 
           { CHAR: I [ "• •" ] } 
           { CHAR: J [ "• — — —" ] } 
           { CHAR: K [ "— • —" ] } 
           { CHAR: L [ "• — • •" ] } 
           { CHAR: M [ "— —" ] } 
           { CHAR: N [ "— •" ] } 
           { CHAR: O [ "— — —" ] } 
           { CHAR: P [ "• — — •" ] } 
           { CHAR: Q [ "— — • —" ] } 
           { CHAR: R [ "• — •" ] } 
           { CHAR: S [ "• • •" ] } 
           { CHAR: T [ "—" ] } 
           { CHAR: U [ "• • —" ] } 
           { CHAR: V [ "• • • —" ] } 
           { CHAR: W [ "• — —" ] } 
           { CHAR: X [ "— • • —" ] }  
           { CHAR: Y [ "— • — —" ] }  
           { CHAR: Z [ "— — • •" ] } [ drop " " ] } case ;

: morse>ch ( morse-substring -- char )
         { { "— — — — —" [ CHAR: 0 ] }
           { "• — — — —" [ CHAR: 1 ] }
           { "• • — — —" [ CHAR: 2 ] }
           { "• • • — —" [ CHAR: 3 ] }
           { "• • • • —" [ CHAR: 4 ] }
           { "• • • • •" [ CHAR: 5 ] }
           { "— • • • •" [ CHAR: 6 ] }
           { "— — • • •" [ CHAR: 7 ] }
           { "— — — • •" [ CHAR: 8 ] }
           { "— — — — •" [ CHAR: 9 ] }
           { "• —" [ CHAR: A ] } 
           { "— • • •" [ CHAR: B ] }
           { "— • — •" [ CHAR: C ] } 
           { "— • •" [ CHAR: D ] } 
           { "• • •" [ CHAR: E ] }
           { "• • — •" [ CHAR: F ] }
           { "— — •" [ CHAR: G ] }
           { "• • • •" [ CHAR: H ] } 
           { "• •" [ CHAR: I ] } 
           { "• — — —" [ CHAR: J ] } 
           { "— • —" [ CHAR: K ] } 
           { "• — • •" [ CHAR: L ] } 
           { "— —" [ CHAR: M ] } 
           { "— •" [ CHAR: N ] } 
           { "— — —" [ CHAR: O ] } 
           { "• — — •" [ CHAR: P ] } 
           { "— — • —" [ CHAR: Q ] } 
           { "• — •" [ CHAR: R ] } 
           { "• • •" [ CHAR: S ] } 
           { "—" [ CHAR: T ] } 
           { "• • —" [ CHAR: U ] } 
           { "• • • —" [ CHAR: V ] } 
           { "• — —" [ CHAR: W ] } 
           { "— • • —" [ CHAR: X ] }  
           { "— • — —" [ CHAR: Y ] }  
           { "— — • •" [ CHAR: Z ] }
           [ drop 32 ] } case ;


: string>morse ( string -- morse-string )
         sequence>cons { } [ ch>morse suffix ] foldl
         "  " join ;

: morse>string ( morse-string -- string )
         R/ [ ]{2,}/ re-split
         [ >string morse>ch ] map >string ;