Limitations of Custom Expressions and Custom Instructions

Custom expressions cannot execute procedural logic; they can only perform simple calculations and parameter handling. Meanwhile, custom instructions do not support returning values.
This creates limitations in many scenarios where procedural steps are required to produce a result.
For example, an expression might need to receive an array parameter, modify the array (add/remove/update elements), and then return the updated result.
Since such operations in Vizzy necessarily involve procedural steps, implementing them becomes cumbersome or even impossible within the current system.