Not public struct Not: Fn Not computes the negation of a boolean expression. Computes the negation of a boolean value, returning true if its argument is false, or false if its argument is true.. Reference. init(_:) Declaration Swift public init(_ expr: Expr) Parameters expr Boolean to negate. © 2018 Fauna, Inc. All rights reserved. (Last updated: 2018-03-21) Generated by jazzy ♪♫ v0.8.2, a Realm project.