Make type annotation optional for self argument of bound methods (#…

…1626)

Make type annotation optional for the first argument (usually named
`self`) of bound methods to conform to PEP 484. Fixes #1578.

This is done by adding the missing type annotation in the syntactic
stage if there is no annotation present.

CHANGELOG.md

@@ -8,6 +8,7 @@ All notable changes to this project will be documented in this file.
 -   #1571 : Add support for the function `tuple`.
 -   #1493 : Add preliminary support for importing classes.
 -   \[INTERNALS\] Add `class_type` attribute to `TypedAstNode`.
+-   #1578 : Allow classes to avoid type annotations for the self argument of a method.
 
 ### Fixed
 

docs/classes.md

@@ -31,23 +31,23 @@ import numpy as np
 from pyccel.decorators import inline
 
 class MyClass:
-    def __init__(self : 'MyClass', param1 : 'int', param2 : 'int'):
+    def __init__(self, param1 : 'int', param2 : 'int'):
         self.param1 = param1
         self.param2 = np.ones(param2)
         print("MyClass Object created!")
 
     @inline
-    def get_param(self : 'MyClass'):
+    def get_param(self):
         print(self.param1, self.param2)
 
 class MyClass1:
-    def __init__(self : 'MyClass1'):
+    def __init__(self):
         print("MyClass1 Object created!")
 
-    def Method1(self : 'MyClass1', param1 : 'MyClass'):
+    def Method1(self, param1 : MyClass):
         self.param = param1
 
-    def Method2(self : 'MyClass1'):
+    def Method2(self):
         return MyClass(2, 4)
 
 if __name__ == '__main__':
@@ -192,4 +192,4 @@ MyClass Object created!
 
 ## Limitations
 
-It's important to note that Pyccel does not support class inheritance, properties, magic methods or class variables. For our first implementation, the focus of Pyccel is primarily on core class functionality and memory management.
+It's important to note that Pyccel does not support class inheritance, properties, magic methods or static class variables. For our first implementation, the focus of Pyccel is primarily on core class functionality and memory management.

pyccel/parser/syntactic.py

@@ -463,6 +463,7 @@ def _visit_AnnAssign(self, stmt):
             return Assign(annotated_lhs, rhs)
 
     def _visit_arguments(self, stmt):
+        is_class_method = len(self._context) > 2 and isinstance(self._context[-3], ast.ClassDef)
 
         if stmt.vararg or stmt.kwarg:
             errors.report(VARARGS, symbol = stmt,
@@ -489,6 +490,18 @@ def _visit_arguments(self, stmt):
                 new_arg.set_current_ast(a)
                 arguments.append(new_arg)
 
+        headers = self.scope.find(self._context[-2].name, 'headers') \
+                if isinstance(self._context[-2], ast.FunctionDef) else None
+
+        if is_class_method and not headers:
+            expected_self_arg = arguments[0]
+            if expected_self_arg.annotation is None:
+                class_name = self._context[-3].name
+                annotation = self._treat_type_annotation(class_name, PyccelSymbol(class_name))
+                arguments[0] = FunctionDefArgument(AnnotatedPyccelSymbol(expected_self_arg.name, annotation),
+                                            annotation=annotation,
+                                            value = expected_self_arg.value)
+
         if stmt.kwonlyargs:
             for a,d in zip(stmt.kwonlyargs,stmt.kw_defaults):
                 annotation=self._treat_type_annotation(a, self._visit(a.annotation))

tests/pyccel/scripts/classes/classes.py

@@ -1,7 +1,7 @@
 # pylint: disable=missing-class-docstring,  missing-function-docstring, missing-module-docstring
 
 class Point(object):
-    def __init__(self : 'Point', x : float, y : float):
+    def __init__(self, x : float, y : float):
         self.x = x
         self.y = y
 

tests/pyccel/scripts/classes/classes_3.py

@@ -2,26 +2,26 @@
 # coding: utf-8
 
 class Point:
-    def __init__(self : 'Point', x : float, y : float):
+    def __init__(self, x : float, y : float):
         self.x = x
         self.X = y
 
-    def set_coordinates(self : 'Point', x : float, y : float):
+    def set_coordinates(self, x : float, y : float):
         self.x = x
         self.X = y
 
-    def get_coordinates(self : 'Point'):
+    def get_coordinates(self):
         return self.x, self.X
 
 class Point1:
-    def __init__(self : 'Point1', x : float):
+    def __init__(self, x : float):
         self.x = x
 
 class Point2:
-    def __init__(self : 'Point2', y : float):
+    def __init__(self, y : float):
         self.y = y
 
-    def test_func(self : 'Point2'):
+    def test_func(self):
         p = Point1(self.y)
         print(p.x)