feat: functions with formal parameters

src/ty/common.rs

@@ -8,7 +8,7 @@ pub struct Catchable {
     msg: Option<String>,
 }
 
-#[derive(Debug, Clone, Hash, PartialEq, Eq, Constructor)]
+#[derive(Debug, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Constructor)]
 pub struct Symbol(EcoString);
 
 impl<T: Into<EcoString>> From<T> for Symbol {
@@ -24,3 +24,12 @@ impl Deref for Symbol {
     }
 }
 
+impl Symbol {
+    pub fn into_inner(self) -> EcoString {
+        self.0
+    }
+
+    pub fn as_inner(&self) -> &EcoString {
+        &self.0
+    }
+}