Printing and parsing of a property map are not inverse operations

[tneele]

In mcrl2/data/detail/data_property_map, there are functions for printing and parsing properties. One would expect that these operations are eachother's inverse. However, when printing a set that contains an element with a comma, this is not the case. See the following example.

parse_set_string(print(std::set<>({"X(n,m:Nat)","Y"})))

leads to something like {"X(n","m:Nat)","Y"}.

I ran into this problem when making some changes to the pbesconstelm algorithm and running the librarytest_mcrl2_pbes_constelm_test test.