r2a(r)=
  n = [1,5,10,50,100,500,1000]
  a,m = 0
  > i, #.size(r)..1, -1
    v,c = n[#.pos("IVXLCDM",#.mid(r,i))]
    ? v<m, v = -v
    ? c>m, m = c
    a += v
  <
  <= a
.

t = ["MMXI","MIM","MCMLVI","MDCLXVI","XXCIII","LXXIIX","IIIIX"]
> i, 1..#.size(t,1)
  #.output(t[i]," = ",r2a(t[i]))
<