feat: add nested class

Author: remigermain

nested_multipart_parser/declare.py

@@ -0,0 +1,55 @@
+class NestedDeclare:
+    def __init__(self, _type=None):
+        self._elements = {}
+        self.set_type(_type)
+    
+    def set_type(self, _type):
+        self._is_dict = _type is dict
+        self._is_list = _type is list
+        self._is_none = _type is None
+    
+    def set_type_from_key(self, key):
+        self.set_type(list if isinstance(key, int) else dict)
+    
+    def conv_value(self, key):
+        value = self._elements[key]
+        if isinstance(value, type(self)):
+            value = value.convert()
+        return value
+
+    def __setitem__(self, key, value):
+        if self._is_none:
+            self.set_type_from_key(key)
+        if isinstance(key, int) and not self._is_list:
+            raise ValueError("int key cant be integer for dict object")
+        if not isinstance(key, int) and self._is_list:
+            raise ValueError("need integer key for list elements")
+        if key in self._elements:
+            raise ValueError("key is already set")
+
+        self._elements[key] = value
+    
+    def __getitem__(self, key):
+        if key not in self._elements:
+            self[key] = type(self)()
+        return self._elements[key]
+    
+    def _convert_list(self):
+        keys = sorted(self._elements.keys())
+        if keys != list(range(len(keys))):
+            raise ValueError("invalid format list keys")
+        
+        return [self.conv_value(key) for key in keys]
+    
+    def _convert_dict(self):
+        return {
+            key: self.conv_value(value)
+            for key, value in self._elements.items()
+        }
+
+    def convert(self):
+        if self._is_none:
+            return None
+        if self._is_list:
+            return self._convert_list()
+        return self._convert_dict()