- Language level inconsistencies eliminated by proposing both
`if` and `else` as circuit-breaking operators
- PEP 532 no longer competes with PEP 505 at all
- Rich comparison chaining split out as PEP 535
- Mark E. Haase is now listed as a co-author (as I was better
able to integrate some of his earlier suggestions)
- acknowledged key feedback on the initial draft
- propose specific Grammar changes
- rename potential boolean circuit breakers so they read
better when using them to explain and/or behaviour
- operator.logical_or -> operator.true
- operator.logical_and -> operator.false
- discuss a problem Guido raised regarding inconsistency
between the proposed operator and conditional expressions
(I think it's fixable, but fixing it would have some
pretty significant consequences for the overall language)
- add today to Post-History
- if-else, and, or are now left alone
- else is introduced as a new short-circuiting binary operator
- "circuit breaking" is introduced as the operator and protocol name
- exists() builtin checks for existence
- missing() builtin checks for non-existence
- "not exists" gives a missing instance and vice-versa
- chained comparison is adjusted to use the new protocol when available
First draft of a proposal that blends PEP 335's concept of allowing
overloading of the logical binary operators with PEP 531's notion
of improved native support for tolerating missing data values.
Nick Coghlan
Guido van Rossum