Shared memory : combine path


to generate keys for the shared memory, could we have a ‘combinepath(x,x)’ function that doesn’t add the project directory to the result.
If this function could handle more than 2 arguments it would be great.
we could build tree keys in 2 steps : aggregate with concatenate → combinetree( )

another useful transformation would be ‘running aggregate’ like the running total: it would make the cumulative aggregation of a column over rows, within a group or not. separator could be ‘,’ and ‘’