Issue #289. Disallow <= outside bloom blocks.

[aarondav]

When used on scratches/interfaces, <= will have no effect outside a bloom block. When used on tables, <= will place the tuples in, available in the next tick.

Disallowing <= loses us nothing that <+ doesn't provide, while also eliminating a user-facing corner case.

Note that inside_budinit was added, because meta_rewrite calls BudCollection <= during the rewrite phase. Otherwise, we just use inside_tick.

The error message looks like this: ../collections.rb:605:in <=' : illegal use of <= outside of bloom block (Bud::CompileError) from XactKVSProtocol.rb:103:in

'

[neilconway]

Thanks for the patch! A few suggested changes:

• Rather than introducing inside_budinit, can we change the problematic meta_rewrite code? e.g., we could have meta_rewrite call BudCollection#merge rather than <=.
• The tests should be updated. As-is, the change causes 13 test failures, which should be fixed; we should also add a test to ensure that an error is correctly raised for this scenario.
• Might be nice to suggest using <+ instead in the error message.

Otherwise no objections.

[aarondav]

I used the budinit thing because I wasn't sure if other people might be using <= similarly. If you're pretty sure that's the only place, or that similar cases would become obvious, I can go ahead and do that.

[neilconway]

Other places should be obvious, I'd think (such code will just produce an error).

[aarondav]

Removed budinit, changed meta_rewrite, updated 13 tests, added one test, and error mention now mentions <+. Of note, the changes to tests did make the notation more consistent -- the use of <= was just randomly interspersed between uses of <+.