Re: Roman numerals , recognizer "0r".

0 VARIABLE FORMER
0 VARIABLE PRESENT
HERE 73 C, 86 C, 88 C, 76 C, 67 C, 68 C, 77 C,  \ I  V  X  L  C  D  M
HERE  0 C, 1 C, 2 C, 10 C, 20 C, 100 C, 200 C,
: VAL ( ch -- u )
  [ 0 ] LITERAL  SWAP
  LITERAL LITERAL
  DO
    DUP I C@ =
    IF  DROP I 7 + C@ DUP 0= SWAP 5 * +  NIP 1 SWAP LEAVE  THEN
  LOOP
  OVER IF NIP ELSE DROP THEN
[ 0 0 ] ; 2DROP
: ROMAN>ARABIC ( addr count -- u )
  [ 0 ] LITERAL -ROT
  0 FORMER !  0 PRESENT !
  OVER + 1-
  DO
    I C@ VAL  DUP PRESENT !
    DUP FORMER @ <
    IF    -
    ELSE  DUP FORMER ! +
    THEN
  -1 +LOOP
;
No error checking; properly formatted
Roman number as input is assumed.
--