VIP: support pythonic slicing

[charles-cooper]

Simple Summary

Allow xs[start:end] instead of slice(xs, start, len)

Motivation

It's more pythonic, less friction for new users.

Backwards Compatibility

We might want to deprecate slice.

Copyright

Copyright and related rights waived via CC0

[fubuloubu]

1. would xs[start:end:step] also work?
2. What are the restrictions on start, end and step in terms of their value? (constants, immutables, vars, etc.)

[charles-cooper]

I think we should disallow step for now

[charles-cooper]

the start and end args could have basically the same restrictions as slice, but maybe also allow negative end (so xs[start:-1] would be equivalent to slice(xs, start, len(xs) - start - 1)

[tylerfxn]

👋 . Good first issue.