[jira] [Commented] (DRILL-7574) Generalize projection parser

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/DRILL-7574?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17032839#comment-17032839 ] 

ASF GitHub Bot commented on DRILL-7574:
---------------------------------------

paul-rogers commented on pull request #1974: DRILL-7574: Generalize the projection parser
URL: https://github.com/apache/drill/pull/1974
 
 
   Adds support for multi-dimensional arrays, and columns
   projected as both an array and a map.
   
   ## Description
   
   EVF contains a bit of code called the"projection parser": it takes a projection list and converts it into a form useful for scan projection. The prior version handled single-level arrays, such as needed for the `columns` column in the text reader. For JSON, we must handle arbitrary column structures such as:
   
   ```
   a, a.b, a[1], a[1][2], a.[1][2].b
   ```
   
   The revised version is more forgiving; it just describes what appears in the projection list without trying to enforce semantic rules like the previous version did.
   
   Modified consumers of the projection parser to reflect the changes.
   
   ## Documentation
   
   This feature is not user-visible.
   
   ## Testing
   
   Added new unit tests, revised existing unit tests. Reran all unit tests.
   
 
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> Generalize projection parser
> ----------------------------
>
>                 Key: DRILL-7574
>                 URL: https://issues.apache.org/jira/browse/DRILL-7574
>             Project: Apache Drill
>          Issue Type: Improvement
>    Affects Versions: 1.17.0
>            Reporter: Paul Rogers
>            Assignee: Paul Rogers
>            Priority: Major
>             Fix For: 1.18.0
>
>
> EVF contains a bit of code called the"projection parser": it takes a projection list and converts it into a form useful for scan projection. The prior version handled single-level arrays, such as needed for the {{`columns`}} column in the text reader. For JSON, we must handle arbitrary column structures such as:
> {noformat}
> a, a.b, a[1], a[1][2], a.[1][2].b
> {noformat}
> Adding the DICT type means that we must be a bit more general in the parser. This ticket fixes these issues.



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