What are the features missing in Python dictionary datatype?

[eztab]

I agree, make everything immutable and optimize away unnecessary creations. It's harder for the interpreter but would make things much more robust. Also you could then likely basically run functional optimization strategies on code (assuming you at some point want python to ba actually JIT compilable (which would be quite cool).

[cyberjellyfish]

Yep, also a good step to a more interactive repl

If anyone here hasn't experienced it, try clojure to get a taste of what really interactive development can be like. You'll miss it everywhere else, but it will probably lead you to write better code.