diff --git a/src/abstract_tree/type.rs b/src/abstract_tree/type.rs
index 8dabb79..213562b 100644
--- a/src/abstract_tree/type.rs
+++ b/src/abstract_tree/type.rs
@@ -14,6 +14,10 @@ pub enum Type {
     Boolean,
     Custom(Identifier),
     Float,
+    Function {
+        parameter_types: Vec<Type>,
+        return_type: Box<Type>,
+    },
     Integer,
     List,
     ListOf(Box<Type>),
@@ -131,6 +135,18 @@ impl Display for Type {
             Type::None => write!(f, "none"),
             Type::Range => write!(f, "range"),
             Type::String => write!(f, "string"),
+            Type::Function {
+                parameter_types,
+                return_type,
+            } => {
+                write!(f, "(")?;
+
+                for r#type in parameter_types {
+                    write!(f, "{} ", r#type)?;
+                }
+
+                write!(f, ") : {return_type}")
+            }
         }
     }
 }
diff --git a/src/abstract_tree/value_node.rs b/src/abstract_tree/value_node.rs
index 418c049..c0be308 100644
--- a/src/abstract_tree/value_node.rs
+++ b/src/abstract_tree/value_node.rs
@@ -44,7 +44,18 @@ impl AbstractTree for ValueNode {
             ValueNode::Range(_) => Type::Range,
             ValueNode::String(_) => Type::String,
             ValueNode::Enum(name, _) => Type::Custom(name.clone()),
-            ValueNode::Function { .. } => todo!(),
+            ValueNode::Function {
+                parameters,
+                return_type,
+                ..
+            } => Type::Function {
+                parameter_types: parameters
+                    .into_iter()
+                    .map(|(_, r#type)| r#type)
+                    .cloned()
+                    .collect(),
+                return_type: Box::new(return_type.clone()),
+            },
         };
 
         Ok(r#type)