add decorator event

pyccolo/__init__.py

@@ -67,6 +67,7 @@
 after_while_test = TraceEvent.after_while_test
 before_lambda = TraceEvent.before_lambda
 after_lambda = TraceEvent.after_lambda
+decorator = TraceEvent.decorator
 before_call = TraceEvent.before_call
 after_call = TraceEvent.after_call
 before_argument = TraceEvent.before_argument

pyccolo/expr_rewriter.py

@@ -701,6 +701,35 @@ def visit_Dict(self, node: ast.Dict):
         node.values = traced_values
         return self.visit_literal(node, should_inner_visit=False)
 
+    def visit_FunctionDef_or_AsyncFunctionDef(
+        self, node: Union[ast.FunctionDef, ast.AsyncFunctionDef]
+    ):
+        self.generic_visit(node.args)
+        for elt in node.body:
+            self.visit(elt)
+        new_decorator_list = []
+        for decorator in node.decorator_list:
+            if not self.handler_predicate_by_event[TraceEvent.decorator](decorator):
+                new_decorator_list.append(self.visit(decorator))
+                continue
+            with fast.location_of(decorator):
+                new_decorator_list.append(
+                    self.emit(
+                        TraceEvent.decorator,
+                        decorator,
+                        ret=self.visit(decorator),
+                        func_node_id=self.get_copy_id_ast(node),
+                    )
+                )
+        node.decorator_list = new_decorator_list
+        return node
+
+    def visit_FunctionDef(self, node: ast.FunctionDef):
+        return self.visit_FunctionDef_or_AsyncFunctionDef(node)
+
+    def visit_AsyncFunctionDef(self, node: ast.AsyncFunctionDef):
+        return self.visit_FunctionDef_or_AsyncFunctionDef(node)
+
     def visit_Return(self, node: ast.Return):
         if node.value is None:
             return node

pyccolo/trace_events.py

@@ -46,6 +46,7 @@ class TraceEvent(Enum):
     before_lambda = "before_lambda"
     after_lambda = "after_lambda"
 
+    decorator = "decorator"
     before_call = "before_call"
     after_call = "after_call"
     before_argument = "before_argument"

test/test_trace_events.py

@@ -365,6 +365,7 @@ def foo():
                 pyc.after_function_execution,
                 pyc.after_call,
                 pyc.after_load_complex_symbol,
+                pyc.decorator,
                 pyc.before_function_body,
                 pyc.before_stmt,
                 pyc.before_assign_rhs,