The layout in the docs / source feels strange with everything buried under the predicate module. The goal seems to be to allow imports like:

use predicates::{predicate, Predicate};

Proposal:

• Move all predicate modules into the root with a pub use in lib.rs
• Move Predicate and BoxedPredicate in dedicated private files in the root with a pub use in lib.rs.
• Create a prelude module that contains
  • Predicate
  • predicate module which only re-exports the factory functions
    • Add a note to the factory functions about this
    • Add a note to the *Predicates about using the factories from predicate.

The standard import would now look like:

use predicates::prelude::*;

Benefits

• Standard import is more consistent with regular stuff
• Source and docs organization will be less nested
• Docs will be a little more organized
• The scope of the predicate module will be narrowed to just factories which imo makes the intent / starting point more clear.