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

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

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]
@@ -838,6 +838,14 @@ make the dictionary type accept it automatically, to insert or refer to the valu
 the empty tuple as key. Moreover, a typing notation such as ``Tuple[]`` can easily
 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
 --------------------------------------------