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https://issues.apache.org/jira/browse/CALCITE-529?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14245859#comment-14245859
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Vladimir Sitnikov commented on CALCITE-529:
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{quote}Do we really need this change?.{quote}
I am creating a {{Project}} or {{TableFuncitonScan}} and I want to be able to
just pass my object.
What is the way to pass "additional" parameter from {{toRel}} kind of code?
{quote} (1) stash it, generate a handle (say a unique string), then dereference
that handle using a system function{quote}
I am assuming you mean {{EnumerableRelImplementor.stash}} since there is no
other stash in Calcite.
It does not work for me since I need to create a {{RexCall(myFunction,
myCustomObject, RexInputRef)}}.
I do not want reimplementing {{EnumberableCalcRel}} just because I need call
{{stash}}.
{quote}It opens up a can of worms if "literals" might not be immutable or
serializable{quote}
There is {{java.sql.Types.JAVA_OBJECT}}, so JDBC spec clearly allows to do a
{{setObject(1, obj, Types.JAVA_OBJECT)}}.
> Allow to pass java object via rexBuilder.makeLiteral()
> ------------------------------------------------------
>
> Key: CALCITE-529
> URL: https://issues.apache.org/jira/browse/CALCITE-529
> Project: Calcite
> Issue Type: Bug
> Affects Versions: 1.0.0-incubating
> Reporter: Vladimir Sitnikov
> Assignee: Julian Hyde
> Labels: newbie
>
> Motivation: Rex is simpler that linq4j.
> For instance,
> 1) Sometimes it is easier to create a {{ProjectRel}} rather than lower the
> expression to low-level linq4j
> 2) XXXToEnumerableRule are easier to accomplish via TableFunctionScan. This
> allows to express the call via Rex and skip linq4j completely.
> For example:
> https://github.com/vlsi/mat-calcite-plugin/blob/master/MatCalcitePlugin/src/com/github/vlsi/mat/optiq/rules/InstanceAccessByClassIdRule.java#L43
> The problem is to pass non-literal java object to enumerable/interpreter
> conventions.
> For enumerable the implementation can use stash. For interpreter it can use
> the value as is, etc.
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