This module computes the perimeter 
\index{curve!perimeter} of a curve $P_1P_2...P_n$ (Dlist),
closed or not, by
$$\mathrm{perimeter(P_1P_2...P_n)} = \sum_{k=1}^{n-1} \|P_{k+1}-P_k\|.$$
With the \verb+-m+ and \verb+M+ options, it also computes
$$\min_k \|P_{k+1}-P_k\| \qquad \mathrm{and} \qquad
\max_k \|P_{k+1}-P_k\|.$$