PEP 655: Motivation: Enables mixed key requiredness in the TypedDict alternative syntax (#2359)

Co-authored-by: Alex Waygood <[email protected]>
Co-authored-by: CAM Gerlach <[email protected]>

Author: 3 people

pep-0655.rst

@@ -55,12 +55,26 @@ a mix of both required and potentially-missing keys:
        title: str
        year: NotRequired[int]
 
+This PEP also makes it possible to define TypedDicts in the
+:pep:`alternative functional syntax <589#alternative-syntax>`
+with a mix of required and potentially-missing keys,
+which is not currently possible at all because the alternative syntax does
+not support inheritance:
+
+::
+
+   Actor = TypedDict('Actor', {
+       'name': str,
+       # "in" is a keyword, so the functional syntax is necessary
+       'in': NotRequired[List[str]],
+   })
+
 
 Rationale
 =========
 
 One might think it unusual to propose syntax that prioritizes marking
-*required* keys rather than syntax for *potentially-missing* keys, as is
+*required* keys rather than *potentially-missing* keys, as is
 customary in other languages like TypeScript:
 
 .. code-block:: typescript
@@ -139,7 +153,7 @@ same time:
        year: NotRequired[Required[int]]  # ERROR
 
 
-The :pep:`alternative syntax <589#alternative-syntax>`
+The :pep:`alternative functional syntax <589#alternative-syntax>`
 for TypedDict also supports
 ``Required[]`` and ``NotRequired[]``: