PEP 637: Allow empty starred arguments (GH-1744)

Co-authored-by: Brandt Bucher <brandtbucher@gmail.com>

Author: stefanoborini

pep-0637.rst

@@ -290,7 +290,7 @@ example use case 1, where a slice is accepted.
 
 The successful implementation of this PEP will result in the following behavior:
 
-1. An empty subscript is still illegal, regardless of context::
+1. An empty subscript is still illegal, regardless of context (see Rejected Ideas)::
 
        obj[]  # SyntaxError
 
@@ -394,7 +394,7 @@ The successful implementation of this PEP will result in the following behavior:
    The following notation equivalence should be honored::
 
        obj[*()]        
-       # Error. Equivalent to obj[]
+       # Equivalent to obj[()]
        
        obj[*(), foo=3] 
        # Equivalent to obj[foo=3]
@@ -414,7 +414,7 @@ The successful implementation of this PEP will result in the following behavior:
    The following notation equivalent should be honored::
 
        obj[**{}]    
-       # Error. Equivalent to obj[]
+       # Equivalent to obj[()]
        
        obj[3, **{}] 
        # Equivalent to obj[3]
@@ -836,7 +836,15 @@ This proposal already established that, in case no positional index is given, th
 passed value must be the empty tuple. Allowing for the empty index notation would
 make the dictionary type accept it automatically, to insert or refer to the value with
 the empty tuple as key. Moreover, a typing notation such as ``Tuple[]`` can easily
-be written as ``Tuple`` without the indexing notation.
+be written as ``Tuple`` without the indexing notation. 
+
+However, subsequent discussion with Brandt Bucher during implementation has revealed
+that the case ``obj[]`` would fit a natural evolution for variadic generics, giving 
+more strength to the above comment. In the end, after a discussion between D'Aprano,
+Bucher and the author, we decided to leave the ``obj[]`` notation as a syntax
+error for now, and possibly extend the notation with an additional PEP to hold
+the equivalence ``obj[]`` as ``obj[()]``. 
+
 
 Sentinel value for no given positional index
 --------------------------------------------