I wrote an implementation of the D-Bus protocol, which has maps, and after doing so I wish it didn't. Maps are a pain for implementors. For example, the semant

I wrote an implementation of the D-Bus protocol, which has maps, and after doing so I wish it didn't. Maps are a pain for implementors. For example, the semantics of duplicate keys are not obvious. Do you throw an error, or keep the first value, or keep the last value, or do something else? Whatever the decision, somebody will be unhappy with it. Better to just give the user a list of (key, value) pairs and let them figure out what to do with it (e.g. pass it to a map construction function that behaves as they like).