METRON-1148: Add SET and MULTISET data structures to stellar

[cestella]

Contributor Comments

With the addition of geohashes, to do analytics like tracking the statistical distribution of the distances of a user's login against the centroid of the user logins across some time, there is a need to be able to store sets (e.g. sets of geohashes) and multisets (sets with multiplicity) in a way that they can be stored by the profiler and merged across time.
This JIRA should add:

• SET_INIT
• SET_ADD
• SET_REMOVE
• SET_MERGE
• MULTISET_INIT
• MULTISET_ADD
• MULTISET_REMOVE
• MULTISET_MERGE
• MULTISET_TO_SET
  These follow the pattern of the other data structures (that are not stellar language primitives)

You can tinker with these in the stellar REPL as manual tests.

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[ottobackwards]

Thanks for the contribution! This looks really nice.
The question I have is the validation of parameters and the default return. With the FUZZY_SCORE effort, we discussed returning a default 0 score when input parameters where wrong, and changed so that errors in parameters where known. This seems to me to be kind of the same thing. If a non-iterable is passed, should it not be an error?

[cestella]

Which method are we talking about, @ottobackwards ?

[cestella]

Nevermind, I know what you're talking about now. Sorry, misunderstood :) Yeah, I'll do a quick check and ensure that exceptions are thrown where appropriate.

[cestella]

Ok, let me know if I missed any that you think should be there.

[ottobackwards]

Thanks Casey, +1 by inspection