I was tasked updating an old maple program (written +20 years ago using Maple version 3 I believe) and came across a line I'm unsure the meaning of. The line is: beta := [rhobar2$rowdim(A)]:

rhobar2 is the square of the mean of a data set and A is a Matrix with 3 columns and 12 rows. I'm just unsure what the $ operator is or is doing to the data. Any help would be appreciated. I'm new to this, sorry if this seems trivial.