Spec is unclear on / operator

[illicitonion]

The spec states that / is a binary operator (a Binop), but doesn't give it any meaning (it's not considered an Arithmetic operation.

It is included as an Augmented assignment (/=), but without behavioural specification.

These all appear in the grammar reference.

Should / be removed from the grammar, or should its behaviour be specified?

[laurentlb]

As in Python 3, // should be integer division and / should be float division. However, the spec doesn't define floats at the moment.

Starlark-Go implementation can support floats behind a flag. If you don't support floats, you should raise an error for the / operator.

Keeping it in the grammar can help tools (e.g. formatter, linter) handle it.

[alandonovan]

This is addressed by #119, which should hopefully be committed later today.