Allow the use of magic methods to describe container methods (pyccel#2016)

Allow the use of magic methods to describe container methods. This is
tested with `set.union` which is called via the `|` operator.

Author: EmilyBourne

CHANGELOG.md

@@ -14,7 +14,6 @@ All notable changes to this project will be documented in this file.
 -   #1693 : Add Python support for list method `remove()`.
 -   #1750 : Add Python support for set method `remove()`.
 -   #1743 : Add Python support for set method `discard()`.
--   #1754 : Add Python support for set method `update()`.
 -   #1893 : Add Python support for set initialisation with `set()`.
 -   #1895 : Add Python support for dict initialisation with `{}`.
 -   #1895 : Add Python support for dict initialisation with `dict()`.
@@ -45,9 +44,11 @@ All notable changes to this project will be documented in this file.
 -   #1583 : Allow inhomogeneous tuples in classes.
 -   #738 : Add support for homogeneous tuples with scalar elements as arguments.
 -   Add a warning about containers in lists.
+-   #2016 : Add support for translating arithmetic magic methods (methods cannot yet be used from Python).
 -   \[INTERNALS\] Add abstract class `SetMethod` to handle calls to various set methods.
 -   \[INTERNALS\] Added `container_rank` property to `ast.datatypes.PyccelType` objects.
 -   \[INTERNALS\] Add a `__call__` method to `FunctionDef` to create `FunctionCall` instances.
+-   \[INTERNALS\] Allow the use of magic methods to describe container methods.
 -   \[DEVELOPER\] Added an improved traceback to the developer-mode errors for errors in function calls.
 
 ### Fixed

developer_docs/semantic_stage.md

@@ -112,7 +112,7 @@ Instead they are recognised via the function [`pyccel.ast.utilities.builtin_func
 Functions from supported libraries are saved in an object of type [`pyccel.ast.core.PyccelFunctionDef`](../pyccel/ast/core.py) when they are imported.
 These functions are handled one of two ways.
 If there is special treatment which requires functions from the `SemanticParser` (e.g. handling inhomogeneous tuples or adding new imports) then a `_build_X` function should be created.
-Differently than the `_visit_X` functions, a `_build_X` function does not take an object of type `X` as argument, but rather a `FunctionCall` to the class `X`. In other words it does not visit `X`, but rather the call `X()`. If `X` represents a method of a class then `_build_X` takes a `DottedName` instead of a `FunctionCall`.
+Differently than the `_visit_X` functions, a `_build_X` function does not take an object of type `X` as argument, but rather a `FunctionCall` to the class `X` and the visited `FunctionCallArgument` objects. In other words it does not visit `X`, but rather the call `X()`. If `X` represents a method of a class then `_build_X` takes a `DottedName` instead of a `FunctionCall`.
 The `SemanticParser._visit_FunctionCall` function will call this visitation function internally if it exists.
 Otherwise the object will be created in the `SemanticParser._handle_function` function and its type will be determined by its constructor.
 

pyccel/ast/class_defs.py

@@ -166,6 +166,8 @@
             PyccelFunctionDef('remove', func_class = SetRemove),
             PyccelFunctionDef('union', func_class = SetUnion),
             PyccelFunctionDef('update', func_class = SetUpdate),
+            PyccelFunctionDef('__or__', func_class = SetUnion),
+            PyccelFunctionDef('__ior__', func_class = SetUpdate),
         ])
 
 #=======================================================================================

pyccel/ast/core.py

@@ -12,6 +12,9 @@
 from pyccel.utilities.stage   import PyccelStage
 
 from .basic     import PyccelAstNode, TypedAstNode, iterable, ScopedAstNode
+
+from .bitwise_operators import PyccelBitOr, PyccelBitAnd
+
 from .builtins  import (PythonEnumerate, PythonLen, PythonMap, PythonTuple,
                         PythonRange, PythonZip, PythonBool, Lambda)
 
@@ -789,7 +792,10 @@ class AugAssign(Assign):
             '-' : PyccelMinus,
             '*' : PyccelMul,
             '/' : PyccelDiv,
-            '%' : PyccelMod}
+            '%' : PyccelMod,
+            '|' : PyccelBitOr,
+            '&' : PyccelBitAnd,
+        }
 
     def __init__(
         self,
@@ -812,8 +818,22 @@ def __repr__(self):
 
     @property
     def op(self):
+        """
+        Get the string describing the operator which modifies the lhs variable.
+
+        Get the string describing the operator which modifies the lhs variable.
+        """
         return self._op
 
+    @property
+    def pyccel_operator(self):
+        """
+        Get the PyccelOperator which modifies the lhs variable.
+
+        Get the PyccelOperator which modifies the lhs variable.
+        """
+        return self._accepted_operators[self._op]
+
     def to_basic_assign(self):
         """
         Convert the AugAssign to an Assign.
@@ -3619,7 +3639,7 @@ def add_new_interface(self, interface):
         interface.set_current_user_node(self)
         self._interfaces += (interface,)
 
-    def get_method(self, name):
+    def get_method(self, name, raise_error = True):
         """
         Get the method `name` of the current class.
 
@@ -3633,6 +3653,11 @@ def get_method(self, name):
         name : str
             The name of the attribute we are looking for.
 
+        raise_error : bool, default=True
+            True if an error should be raised, False if None should be returned if
+            the method is not found.
+            False if None can be returned instead.
+
         Returns
         -------
         FunctionDef
@@ -3648,8 +3673,11 @@ def get_method(self, name):
             try:
                 name = self.scope.get_expected_name(name)
             except RuntimeError:
-                errors.report(f"Can't find method {name} in class {self.name}",
-                        severity='fatal', symbol=self)
+                if raise_error:
+                    errors.report(f"Can't find method {name} in class {self.name}",
+                            severity='fatal', symbol=self)
+                else:
+                    return None
 
         try:
             method = next(i for i in chain(self.methods, self.interfaces) if i.name == name)
@@ -3659,11 +3687,12 @@ def get_method(self, name):
             n_classes = len(self.superclasses)
             while method is None and i<n_classes:
                 try:
-                    method = self.superclasses[i].get_method(name)
+                    method = self.superclasses[i].get_method(name, raise_error)
                 except StopIteration:
                     method = None
+                i += 1
 
-        if method is None:
+        if method is None and raise_error:
             errors.report(f"Can't find method {name} in class {self.name}",
                     severity='fatal', symbol=self)
 

pyccel/naming/cnameclashchecker.py

@@ -81,9 +81,10 @@ def get_collisionless_name(self, name, symbols):
         str
             A new name which is collision free.
         """
-        if len(name)>4 and all(name[i] == '_' for i in (0,1,-1,-2)):
-            # Ignore magic methods
+        if name in ('__init__', '__del__'):
             return name
+        if len(name)>4 and all(name[i] == '_' for i in (0,1,-1,-2)):
+            name = 'operator' + name[1:-2]
         if name[0] == '_':
             name = 'private'+name
         return self._get_collisionless_name(name, symbols)

pyccel/naming/fortrannameclashchecker.py

@@ -91,9 +91,10 @@ def get_collisionless_name(self, name, symbols):
         str
             A new name which is collision free.
         """
-        if len(name)>4 and all(name[i] == '_' for i in (0,1,-1,-2)):
-            # Ignore magic methods
+        if name in ('__init__', '__del__'):
             return name
+        if len(name)>4 and all(name[i] == '_' for i in (0,1,-1,-2)):
+            name = 'operator' + name[1:-2]
         if name[0] == '_':
             name = 'private'+name
         name = self._get_collisionless_name(name, symbols)