Feature request #9546

Expression Contexts

Added by Martin Dobias over 9 years ago. Updated about 8 years ago.

Pull Request or Patch supplied:No Resolution:
Easy fix?:No Copied to github as #:18133


There is an increasing number of additional features in expression engine that make sense only in particular context. These features are available either directly in QgsExpression API (e.g. $rownum, $scale) or through "special columns" (e.g. $map, $page, ...). Additionally, with special columns, their value is shared between all QgsExpression instances, which may eventually lead to problems with concurrency (especially with multi-threading).

More thoughts:
https://www.mail-archive.com/[email protected]/msg19488.html

Related issues

Related to QGIS Application - Feature request #10539: QgsExpression instance variables Closed 2014-06-10


#1 Updated by Nathan Woodrow about 8 years ago

  • Status changed from Open to Closed

Already done thanks to Nyall

Also available in: Atom PDF