- proposed precondition operator is now "?then"
- discusses the possible use of mathematical existence notation
- discusses some of the implications of different design decisions
- assorted other fixes and clarifications
Based on the last round of PEP 505 discussions, I'm seeing a
lot more merit in the general idea, but have some strong opinions
on how to describe the concepts to current and new Python users.
Those opinions are different enough from what's currently in PEP
505 that I think writing a competing PEP is the most useful way to
articulate them.