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https://issues.apache.org/jira/browse/CASSANDRA-7813?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Robert Stupp updated CASSANDRA-7813:
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Attachment: 7813v7.txt
Attached v7 (merge with trunk + merge conflicts resolved, no other changes)
> Decide how to deal with conflict between native and user-defined functions
> --------------------------------------------------------------------------
>
> Key: CASSANDRA-7813
> URL: https://issues.apache.org/jira/browse/CASSANDRA-7813
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Sylvain Lebresne
> Assignee: Robert Stupp
> Labels: cql
> Fix For: 3.0
>
> Attachments: 7813.txt, 7813v2.txt, 7813v3.txt, 7813v4.txt,
> 7813v5.txt, 7813v6.txt, 7813v7.txt
>
>
> We have a bunch of native/hardcoded functions (now(), dateOf(), ...) and in
> 3.0, user will be able to define new functions. Now, there is a very high
> change that we will provide more native functions over-time (to be clear, I'm
> not particularly for adding native functions for allthethings just because we
> can, but it's clear that we should ultimately provide more than what we
> have). Which begs the question: how do we want to deal with the problem of
> adding a native function potentially breaking a previously defined
> user-defined function?
> A priori I see the following options (maybe there is more?):
> # don't do anything specific, hoping that it won't happen often and consider
> it a user problem if it does.
> # reserve a big number of names that we're hoping will cover all future need.
> # make native function and user-defined function syntactically distinct so it
> cannot happen.
> I'm not a huge fan of solution 1). Solution 2) is actually what we did for
> UDT but I think it's somewhat less practical here: there is so much types
> that it makes sense to provide natively and so it wasn't too hard to come up
> with a reasonably small list of types name to reserve just in case. This
> feels a lot harder for functions to me.
> Which leaves solution 3). Since we already have the concept of namespaces for
> functions, a simple idea would be to force user function to have namespace.
> We could even allow that namespace to be empty as long as we force the
> namespace separator (so we'd allow {{bar::foo}} and {{::foo}} for user
> functions, but *not* {{foo}} which would be reserved for native function).
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