Re-export evaluators in eval module

src/eval.rs

@@ -4,6 +4,12 @@ pub mod compose;
 pub mod differentiate;
 pub mod simplify;
 
+pub use normalise::*;
+pub use const_fold::*;
+pub use compose::*;
+pub use differentiate::*;
+pub use simplify::*;
+
 #[derive(Debug, PartialEq)]
 pub enum Error {
 	UnsupportedExpression,