RosettaCodeData/Task/Roman-numerals-Decode/Tcl/roman-numerals-decode-1.tcl

proc fromRoman rnum {
    set map {M 1000+ CM 900+ D 500+ CD 400+ C 100+ XC 90+ L 50+ XL 40+ X 10+ IX 9+ V 5+ IV 4+ I 1+}
    expr [string map $map $rnum]0}
}