/examples/rosetta_code/roman_numerals.rx

This is a port of the Forth code; but returns a string rather than displaying
the roman numerals. It only handles numbers between 1 and 3999.

: vector ( ...n"- )
  here [ &, times ] dip : .data ` swap ` + ` @ ` do ` ; ;
: .I  dup     @ ^buffer'add ;
: .V  dup 1 + @ ^buffer'add ;
: .X  dup 2 + @ ^buffer'add ;

[ .I .X       drop ]
[ .V .I .I .I drop ]
[ .V .I .I    drop ]
[ .V .I       drop ]
[ .V          drop ]
[ .I .V       drop ]
[ .I .I .I    drop ]
[ .I .I       drop ]
[ .I          drop ]
&drop
10 vector .digit

: record ( an- )
  10 /mod dup [ [ over 2 + ] dip record ] &drop if .digit ;
: toRoman   ( n-a )
  here ^buffer'set
  dup 1 3999 within 0 =
  [ "EX LIMITO!\n" ] [ "IVXLCDM" swap record here ] if ;