so this turned out to be rather expensive,
while actually not difficult to implement.
On the way, I've learned
- how to build a backtracking matcher, based on
a filtering (monadic) structure and chained lambdas
- learned the hard way how (not) to return a container
by move-reference
- made first contact with the regular expressions
now available from the standard library
Ichthyostega
c8068496d1