initial implementation

Author: Vipul-Cariappa

python/cppyy/_cpython_cppyy.py

@@ -9,6 +9,7 @@
     'load_reflection_info',
     'addressof',
     'bind_object',
+    'generate_typehints',
     'nullptr',
     'default',
     '_backend',
@@ -188,6 +189,7 @@ def add_default_paths():
 bind_object   = _backend.bind_object
 nullptr       = _backend.nullptr
 default       = _backend.default
+generate_typehints   = _backend.generate_typehints
 
 def load_reflection_info(name):
 #    with _stderr_capture() as err:

python/cppyy/_pypy_cppyy.py

@@ -10,6 +10,7 @@
     'gbl',
     'addressof',
     'bind_object',
+    'generate_typehints',
     'nullptr',
     ]
 

test/test_typehints.py

@@ -0,0 +1,100 @@
+from pytest import raises
+
+
+class TestTypeHints:
+    def setup_class(cls):
+        import cppyy
+
+        cppyy.cppdef(
+            r"""
+            namespace TypeHints {
+                int x = 10;
+                template <typename T>
+                struct MyTKlass{
+                    T obj;
+                };
+                struct MyKlass {
+                    std::string name = "MyKlass";
+                    bool flag = false;
+                    std::vector<int> array = {};
+                    float callme(std::string a, bool b, std::vector<int> c) { return 0.0f; }
+                    template <typename T>
+                    T callme(T v) { return v; }
+                };
+                typedef MyKlass Klass;
+                typedef MyTKlass<float> KlassFloat;
+                float fn(std::string a, bool b, std::vector<int> c) { return 0.0f; }
+                template <typename T>
+                T tmpl_fn(T v) { return v; }
+            } // namespace TypeHints
+            int x = 10;
+            double y = 10;
+            unsigned short z = 10;
+            char a = 'a';
+            signed char sa = 'a';
+            unsigned char usa = 'a';
+            template <typename T>
+            struct MyTKlass{
+                T obj;
+            };
+            struct MyKlass {
+                std::string name = "MyKlass";
+                bool flag = false;
+                std::vector<int> array = {};
+                float callme(std::string a, bool b, std::vector<int> c) { return 0.0f; }
+                template <typename T>
+                T callme(T v) { return v; }
+            };
+            float callme(std::string a, bool b, std::vector<int> c) { return 0.0f; }
+            template <typename T>
+            T tmpl_fn(T v) { return v; }
+            typedef MyKlass Klass;
+            typedef MyTKlass<float> KlassFloat;
+        """
+        )
+
+    def test_invalids(self):
+        from cppyy import gbl, generate_typehints
+
+        typehint = generate_typehints("x")
+        assert "x: int\n" == typehint
+        typehint = generate_typehints("y")
+        assert "y: float\n" == typehint
+        typehint = generate_typehints("z")
+        assert "z: int\n" == typehint
+        typehint = generate_typehints("a")
+        assert "a: str\n" == typehint
+        typehint = generate_typehints("sa")
+        assert "sa: int\n" == typehint
+        typehint = generate_typehints("usa")
+        assert "usa: int\n" == typehint
+
+        with raises(NotImplementedError) as err:
+            generate_typehints("MyKlass")
+        assert "class" in str(err)
+
+        typehint = generate_typehints("callme")
+        assert (
+            '@overload\ndef callme (a: "std.string", b: bool, c: "std.vector[int]") -> float: ...\n'
+            == typehint
+        )
+
+        typehint = generate_typehints("Klass")
+        assert "Klass = MyKlass\n" == typehint
+
+        typehint = generate_typehints("KlassFloat")
+        assert "KlassFloat = \"MyTKlass[float]\"\n" == typehint
+
+        with raises(NotImplementedError) as err:
+            generate_typehints("MyTKlass")
+
+        with raises(NotImplementedError) as err:
+            generate_typehints("TypeHints")
+        assert "namespace" in str(err)
+
+        with raises(TypeError) as err:
+            generate_typehints("unknown")
+        assert "Unknown Type" in str(err)
+
+        with raises(TypeError) as err:
+            generate_typehints("TypeHints::x")