For example,

`A = [1 2 3; 4 5 6];`

B can be either a N x 3 matrix or empty like the below:

`B = [];`

When B is empty, why couldn’t I append B to A

`C = vcat(A, B);`

Error message:

`ArgumentError: number of columns of each array must match (got (3, 1))`

Instead of throwing out an error, do you think Julia should instead handle this situation differently, i.e., the above equation of `C = vcat(A, B)`

should create a C that is equal to A, when B is empty?