Function or_collect 

pub fn or_collect<I>(iter: I) -> Option<Expression>
where
    I: IntoIterator<Item = Expression>,

Collects a list of ored values into a single expression using a balanced tree.

This creates a balanced binary tree to avoid deep nesting that could cause stack overflow during drop or evaluation.

[a, b, c, d] => or(or(a, b), or(c, d))