diff --git a/src/parser/exiting.rs b/src/parser/exiting.rs
new file mode 100644
index 0000000..e75b105
--- /dev/null
+++ b/src/parser/exiting.rs
@@ -0,0 +1,10 @@
+pub enum ExitClass {
+    /// Headlines and sections.
+    Document,
+
+    /// Elements who take priority over beta elements when matching.
+    Alpha,
+
+    /// Elements who cede priority to alpha elements when matching.
+    Beta,
+}
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index 7b32ed3..8f63930 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -3,6 +3,7 @@ mod document;
 mod drawer;
 mod element;
 mod error;
+mod exiting;
 mod footnote_definition;
 mod greater_block;
 mod greater_element;