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https://issues.apache.org/jira/browse/PIG-1693?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13011378#comment-13011378
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Xuefu Zhang commented on PIG-1693:
----------------------------------
I have reviewed the parser related changes:
1. in LogicalPlanGenerator.g
$expr = builder.buildRangeProjectExpr(
loc, plan, $GScope::currentOp,
$statement::inputIndex,
startExpr == null ? null : startExpr.expr,
endExpr == null ? null : endExpr.expr
);
instead of startExpr == null ? null : startExpr.expr, just use
$startExpr.expr.
2. LogicalPlanBuilder.java
try {
plan.removeAndReconnect(startExpr);
plan.removeAndReconnect(endExpr);
} catch (FrontendException e) {
throw new ParserValidationException(intStream, loc, e);
}
It is probably better to check if startExpr and endExpr are null.
3. An observation. ProjectExpression class seems getting a little overloaded.
We might need to consider subclass it to take care of STAR, RANGE, etc, though
it doesn't have to happen now.
> support project-range expression. (was: There needs to be a way in foreach to
> indicate "and all the rest of the fields" )
> -------------------------------------------------------------------------------------------------------------------------
>
> Key: PIG-1693
> URL: https://issues.apache.org/jira/browse/PIG-1693
> Project: Pig
> Issue Type: New Feature
> Components: impl
> Reporter: Alan Gates
> Assignee: Thejas M Nair
> Fix For: 0.9.0
>
> Attachments: PIG-1693.1.patch
>
>
> A common use case we see in Pig is people have many columns in their data and
> they only want to operate on a few of them. Consider for example if before
> storing data with ten columns, the user wants to perform a cast on one column:
> {code}
> ...
> Z = foreach Y generate (int)firstcol, secondcol, thridcol, forthcol,
> fifthcol, sixthcol, seventhcol, eigthcol, ninethcol, tenthcol;
> store Z into 'output';
> {code}
> Obviously this only gets worse as the user has more columns. Ideally the
> above could be transformed to something like:
> {code}
> ...
> Z = foreach Y generate (int)firstcol, "and all the rest";
> store Z into 'output'
> {code}
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