1 files changed, 28 insertions, 0 deletions
diff --git a/libs/plugin_python/src/pybind11-utils/functional.cpp b/libs/plugin_python/src/pybind11-utils/functional.cpp
new file mode 100644
index 0000000..4cc7b6c
--- /dev/null
+++ b/libs/plugin_python/src/pybind11-utils/functional.cpp
@@ -0,0 +1,28 @@
+#include "pybind11_utils/functional.h"
+
+namespace py = pybind11;
+
+namespace mo2::python::detail {
+
+    bool has_compatible_arity(py::function fn, std::size_t arity)
+    {
+        auto inspect    = py::module_::import("inspect");
+        auto arg_spec   = inspect.attr("getfullargspec")(fn);
+        py::object args = arg_spec.attr("args"), varargs = arg_spec.attr("varargs"),
+                   defaults = arg_spec.attr("defaults");
+
+        auto args_count     = args.is(py::none()) ? 0 : py::len(args);
+        auto defaults_count = defaults.is(py::none()) ? 0 : py::len(defaults);
+
+        if (inspect.attr("ismethod")(fn).cast<bool>() && py::hasattr(fn, "__self__")) {
+            --args_count;
+        }
+
+        auto required_count = args_count - defaults_count;
+
+        return required_count <= arity  // cannot require more parameters than given,
+               && (args_count >= arity ||
+                   !varargs.is_none());  // must accept enough parameters.
+    }
+
+}  // namespace mo2::python::detail