is there any plan to insert lists in Stan language?
I think they could be quite powerful, because sometimes a collection of arrays do not have the same length.
For example, recently I found myself in the situation of needing this:
phi = simplex[P,Q,M]
[simplex, simplex, simplex]
In the way to constrain by groups
simplex * 0.2 + simplex * 0.4 + simplex * 0.4 = 1
or in a constrained sum of Bob
if I could program alpha_raw as list I could deal with any hierarchy without hard coding in the model