SELECT ARRAY[1, 2.2, v] FROM t;
I think there is catch here.  Now if this is my query from my resultset I would do rs.getArray() ? Correct?  If this is wrong then my following comments are invalid.
If yes, then how to create this as an array in rs.getValue()?  The expression ARRAY[1,12,v] is going to be of type ArrayConstructorExpression. 
1, 2 are going to be Literal Expressions. And they are not persisted anywhere.
v - the column reference is going to be of type KeyValueColExpression.  
Now I can create an Array with this, but how to set the ptr that comes in ExpressionProjector.getValue(). Because that ptr will only have the v (column reference's internal byte[]).  I think this is bit tricky.