M{1,3}
((C{1,3})([^DM]|$))|(CD)|(DC{0,3})|(CM)
((X{1,3})([^LC]|$))|(XL)|(LX{0,3})|(XC)
((I{1,3})([^VX]|$))|(IV)|(VI{0,3})|(IX)
*/
// Javascript
function 2arabic(c) {
switch(c) {
case 'I': return 1; break;
case 'V': return 5; break;
case 'X': return 10; break;
case 'L': return 50; break;
case 'C': return 100; break;
case 'D': return 500; break;
case 'M': return 1000; break;
}
}
var roman = 'MCMLXVIII';
var arabic = 0;
var previous = 0;
var current = 0;
for(i=0; i<roman.length; i++) {
current
= 2arabic(roman.charAt(i));
if(previous && previous<current)
arabic -= previous;
else arabic += previous;
previous = current;
}
arabic += current;
