Piping

The pipe operator (->) allows you to chain operations together. The result of the previous operation is passed as the first argument to the next operation.

This allows you to "flip" your code, where a(b) becomes b -> a().

Why would you use it?

Consider a chain of operations like this:

WHERE(WHERE([1, 2, 3, 4, 5, 6], $current > 2), $current < 5)

This is slightly hard to read, and it's easy to get lost in the parenthesis. With piping, you can write it like this:

[1, 2, 3, 4, 5, 6]
    -> WHERE($current > 2)
    -> WHERE($current < 5) 

This works when working with record data as well. These 2 are equivalent:

Evaluator.run('MAP(WHERE(WHERE(ChildAccounts, NumberOfEmployees > 10), AnnualRevenue > 200), Name)', recordId);

Evaluator.run(
    'ChildAccounts ' +
    '-> WHERE(AnnualRevenue > 200) ' +
    '-> WHERE(NumberOfEmployees > 10) ' +
    '-> MAP(Name)', 
    recordId);