Implement function calls

src/abstract_tree/function_call.rs

@@ -61,6 +61,12 @@ impl AbstractTree for FunctionCall {
             results.push(result);
         }
 
+        for identifier in definition.identifiers() {
+            let key = identifier.inner();
+
+            context.remove(&key);
+        }
+
         Ok(Value::List(results))
     }
 }

src/evaluator.rs

@@ -86,8 +86,6 @@ impl<'context, 'code> Evaluator<'context, 'code> {
         let item_count = root_node.child_count();
         let mut results = Vec::with_capacity(item_count);
 
-        println!("{}", root_node.to_sexp());
-
         for item_node in root_node.children(&mut cursor) {
             let item_result = Item::from_syntax_node(item_node, self.source);
 

src/value/variable_map.rs

@@ -108,6 +108,13 @@ impl VariableMap {
         }
     }
 
+    /// Removes and assignmed variable.
+    ///
+    /// TODO: Support dot notation.
+    pub fn remove(&mut self, key: &str) -> Option<Value> {
+        self.variables.remove(key)
+    }
+
     /// Returns a reference to the inner BTreeMap.
     pub fn inner(&self) -> &BTreeMap<String, Value> {
         &self.variables