Add setdefault classes for dict (pyccel#2033)

Add setdefault classes for dict in python. Fixes pyccel#1888

---------

Co-authored-by: Emily Bourne <[email protected]>

Author: learning-dev

AUTHORS

@@ -35,4 +35,5 @@ Contributors
 * Shoaib Moeen
 * Kush Choudhary
 * Emmmanuel Ferdman
+* Mohammed Ayaz Shaikh
 * Amir Movassaghi

CHANGELOG.md

@@ -19,6 +19,7 @@ All notable changes to this project will be documented in this file.
 -   #1895 : Add Python support for dict initialisation with `dict()`.
 -   #1886 : Add Python support for dict method `pop()`.
 -   #1887 : Add Python support for dict method `popitem()`.
+-   #1888 : Add Python support for dict method `setdefault()`.
 -   #1885 : Add Python support for dict method `get()`.
 -   #1844 : Add line numbers and code to errors from built-in function calls.
 -   #1655 : Add the appropriate C language equivalent for declaring a Python `list` container using the STC library.

docs/builtin-functions.md

@@ -128,7 +128,7 @@ Python contains a limited number of builtin functions defined [here](https://doc
 | `pop` | Python-only |
 | `popitem` | Python-only |
 | `reversed` | No |
-| `setdefault` | No |
+| `setdefault` | Python-only |
 | `update` | No |
 | `values` | No |
 

pyccel/ast/builtin_methods/dict_methods.py

@@ -17,6 +17,7 @@
            'DictMethod',
            'DictPop',
            'DictPopitem',
+           'DictSetDefault',
            )
 
 #==============================================================================
@@ -176,4 +177,62 @@ def default_value(self):
         """
         return self._args[1]
 
+#==============================================================================
+
+class DictSetDefault(DictMethod):
+    """
+    Represents a call to the .setdefault() method.
+
+    The setdefault() method set an element in the dict. The element is set
+    via a key and a value. If the value is not passed then default value is set
+    as the value.
+
+    If returns the value and if it is not present in the dictionary then the default
+    value is returned.
+
+    Parameters
+    ----------
+    dict_obj : TypedAstNode
+        The object from which the method is called.
+
+    k : TypedAstNode
+        The key which is used to set the value from the dictionary.
+
+    d : TypedAstNode, optional
+        The value that should be returned. if the value is not present in the
+        dictionary then default value is returned.
+    """
+    __slots__ = ('_class_type', '_shape')
+    name = 'setdefault'
+
+    def __init__(self, dict_obj, k, d = None):
+        dict_type = dict_obj.class_type
+        self._class_type = dict_type.value_type
+
+        self._shape = (None) * self._class_type.rank if self._class_type.rank else None
 
+        if k.class_type != dict_type.key_type:
+            raise TypeError(f"Key passed to setdefault method has type {k.class_type}. Expected {dict_type.key_type}")
+        if d is None:
+            raise TypeError("None cannot be used as the default argument for the setdefault method.")
+        if d and d.class_type != dict_type.value_type:
+            raise TypeError(f"Default value passed to setdefault method has type {d.class_type}. Expected {dict_type.value_type}")
+        super().__init__(dict_obj, k, d)
+
+    @property
+    def key(self):
+        """
+        The key that is used to select the element from the dict.
+
+        The key that is used to select the element from the dict.
+        """
+        return self._args[0]
+
+    @property
+    def default_value(self):
+        """
+        The value that should be returned if the key is not present in the dictionary.
+
+        The value that should be returned if the key is not present in the dictionary.
+        """
+        return self._args[1]

pyccel/ast/class_defs.py

@@ -11,7 +11,8 @@
 from pyccel.ast.builtin_methods.list_methods import (ListAppend, ListInsert, ListPop,
                                                      ListClear, ListExtend, ListRemove,
                                                      ListCopy, ListSort)
-from pyccel.ast.builtin_methods.dict_methods  import DictPop, DictPopitem, DictGet
+from pyccel.ast.builtin_methods.dict_methods  import( DictPop, DictPopitem, DictGet,
+                                                     DictSetDefault)
 
 from .builtins   import PythonImag, PythonReal, PythonConjugate
 from .core       import ClassDef, PyccelFunctionDef
@@ -177,6 +178,7 @@
             PyccelFunctionDef('get', func_class = DictGet),
             PyccelFunctionDef('pop', func_class = DictPop),
             PyccelFunctionDef('popitem', func_class = DictPopitem),
+            PyccelFunctionDef('setdefault', func_class = DictSetDefault),
         ])
 
 #=======================================================================================

tests/epyccel/test_epyccel_dicts.py

@@ -192,6 +192,19 @@ def dict_contains():
     assert isinstance(python_result, type(pyccel_result))
     assert python_result == pyccel_result
 
+
+def test_set_default(python_only_language):
+    def set_default():
+        a = {1: 1.0, 2:2.0}
+        b = a.setdefault(1, 3.0)
+        c = a.setdefault(3, 4.0)
+        return a, b, c
+    epyc_str_keys = epyccel(set_default, language = python_only_language)
+    pyccel_result = epyc_str_keys()
+    python_result = set_default()
+    assert isinstance(python_result, type(pyccel_result))
+    assert python_result == pyccel_result
+
 def test_dict_ptr(python_only_language):
     def dict_ptr():
         a = {1:1.0, 2:2.0, 3:3.0}