Hi Nathan Only partially related to this thread as a shy reminder: My intern Simran recently has made a pull request [*] for your nice Expressions Plus Plugin QGIS plugin.
These are the proposed additional functions: * max_incremented() - an "autoincrement" id function * hstore - support of a key-value pair set/string * nullif() - returns None if arg_1 equals to arg_2 otherwise arg_1 * get_env_variable() and set_env_variable() * jitter_geometry() These expression functions could be of interest for workshops like the mentioned one. Cheers, Stefan [*] https://github.com/NathanW2/qgsexpressionsplus/pull/8 2017-06-19 14:36 GMT+02:00 Neumann, Andreas <[email protected]>: > Hi Nathan, > > Thank you for the explanation. Makes sense. I will pass this on in the > workshop. > > Andreas > > On 2017-06-19 14:12, Nathan Woodrow wrote: > > Hey Andreas, > > They are really two different things. $geometry is really a function that > takes no arguments. This has been deprecated in favour calling with () e.g > geometry(). @ is only for variables. > > So you can explain it that $ used to be a shorthand way of calling a > function that took no arguments which has now been replaced with () at the > end to call it. $area = area(). This becomes important because now we > support optional arguments meaning you can take 0 to N arguments. > > - Nathan > > On Mon, Jun 19, 2017 at 9:53 PM, Neumann, Andreas <[email protected]> > wrote: >> >> Hi, >> >> While preparing for a workshop on expressions I wonder how to explain why >> some variables are referenced with the $ sign (like $geometry) while other >> variables start with the @ sign, like @row_number, @layer_name. >> >> I know that it has historical reasons and that variables with the @ sign >> are newer and are implemented using a different technology. >> >> But are there plans to get rid of the old $ sign notation and move >> everything to the @ sign notation? >> >> Just wonder how I best explain this to the participants of the workshop. >> >> Thanks for your reply, >> >> Andreas >> >> >> >> _______________________________________________ >> QGIS-Developer mailing list >> [email protected] >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer > > > > > > _______________________________________________ > QGIS-Developer mailing list > [email protected] > List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer _______________________________________________ QGIS-Developer mailing list [email protected] List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer
