Start working on generic managers, see #1413

jedi/inference/gradual/generics.py

@@ -1,5 +1,6 @@
-from jedi.inference.base_value import ValueSet, Value, \
-    iterator_to_value_set, LazyValueWrapper, ValueWrapper
+from jedi.cache import memoize_method
+from jedi.inference.utils import to_list
+from jedi.inference.base_value import ValueSet
 from jedi.inference.value.iterable import SequenceLiteralValue
 from jedi.inference.helpers import is_string
 
@@ -12,16 +13,62 @@ def iter_over_arguments(maybe_tuple_value, defining_context):
         else:
             yield ValueSet([maybe_tuple_value])
 
-    def resolve_forward_references(value_set):
-        for value in value_set:
-            if is_string(value):
-                from jedi.inference.gradual.annotation import _get_forward_reference_node
-                node = _get_forward_reference_node(defining_context, value.get_safe_value())
-                if node is not None:
-                    for c in defining_context.infer_node(node):
-                        yield c
-            else:
-                yield value
-
     for value_set in iterate():
-        yield ValueSet(resolve_forward_references(value_set))
+        yield ValueSet(_resolve_forward_references(defining_context, value_set))
+
+
+def _resolve_forward_references(context, value_set):
+    for value in value_set:
+        if is_string(value):
+            from jedi.inference.gradual.annotation import _get_forward_reference_node
+            node = _get_forward_reference_node(context, value.get_safe_value())
+            if node is not None:
+                for c in context.infer_node(node):
+                    yield c
+        else:
+            yield value
+
+
+class LazyGenericManager(object):
+    def __init__(self, context_of_index, index_value):
+        self._context_of_index = context_of_index
+        self._index_value = index_value
+
+    @memoize_method
+    def __getitem__(self, index):
+        return self._list()[index]()
+
+    def __len__(self):
+        return len(self._list())
+
+    @memoize_method
+    @to_list
+    def _list(self):
+        if isinstance(self._index_value, SequenceLiteralValue):
+            for lazy_value in self._index_value.py__iter__(contextualized_node=None):
+                yield lambda: _resolve_forward_references(
+                    self._context_of_index,
+                    lazy_value.infer()
+                )
+        else:
+            yield lambda: ValueSet([
+                _resolve_forward_references(self._context_of_index, self._index_value)
+            ])
+
+    def __iter__(self):
+        return iter(self._iterate())
+
+
+class ListGenericManager(object):
+    def __init__(self, lst):
+        self._lst = lst
+
+    def __getitem__(self, index):
+        return self._lst[index]
+
+    def __len__(self):
+        return len(self._lst)
+
+    def __iter__(self):
+        for value_set in self._lst:
+            yield lambda: value_set