I've now got to the point where the Map concept can be defined properly. You can see a working example here:
[https://github.com/nim-lang/Nim/blob/ecdf7a7a4f1bc9e6210a0d4533302ca77ce06296/tests/concepts/tmapconcept.nim](https://github.com/nim-lang/Nim/blob/ecdf7a7a4f1bc9e6210a0d4533302ca77ce06296/tests/concepts/tmapconcept.nim) There are a few more planned additions for tomorrow and then I'll document everything. @more, @andrea, are you guys working on the same codebase?
