diff --git a/src/lib.rs b/src/lib.rs
index 64d2780..f63a799 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -11,6 +11,7 @@ mod value;
 pub use configuration::{Configuration, EmptyConfiguration, HashMapConfiguration};
 pub use error::Error;
 pub use function::Function;
+pub use tree::Node;
 pub use value::Value;
 
 pub fn eval(string: &str) -> Result<Value, Error> {
@@ -24,6 +25,10 @@ pub fn eval_with_configuration(
     tree::tokens_to_operator_tree(token::tokenize(string)?)?.eval(configuration)
 }
 
+pub fn build_operator_tree(string: &str) -> Result<Node, Error> {
+    tree::tokens_to_operator_tree(token::tokenize(string)?)
+}
+
 #[cfg(test)]
 mod test {
     use crate::{eval, value::Value};