Add pending acceptance note and some TODOs

pep-0572.rst

@@ -17,6 +17,15 @@ Abstract
 This is a proposal for creating a way to assign to variables within an
 expression using the notation ``NAME := expr``.
 
+Pending Acceptance
+------------------
+
+This PEP will be accepted, however it needs some editing for clarity
+and exact specification.  A final draft will be posted to python-dev.
+Note that alternate syntax proposals ("EXPR as NAME", "EXPR given
+...") are no longer under consideration.  Hopefully the final draft
+will be posted well before the end of July 2018.
+
 
 Rationale
 =========
@@ -235,6 +244,8 @@ above scope rules as illustrated by ``[i := i+1 for i in range(5)]``
 or ``[[(j := j) for i in range(5)] for j in range(5)]``.  Note that
 this exception also applies to ``[i := 0 for i, j in stuff]``.)
 
+TODO: prohibit [... for i in i := ...]
+
 A further exception applies when an assignment expression occurrs in a
 comprehension whose containing scope is a class scope.  If the rules
 above were to result in the target being assigned in that class's
@@ -248,6 +259,10 @@ this special case may be removed from the specification of assignment
 expressions.  Note that the problem already exists for *using* a
 variable defined in the class scope from a comprehension.)
 
+TODO: nested comprehensions
+
+TODO: use a a subclass of SyntaxError for various prohibitions?
+
 Relative precedence of ``:=``
 -----------------------------