Record pronouncement on conditional expressions.

pep-0000.txt

@@ -63,6 +63,7 @@ Index by Category
 
  Accepted PEPs (accepted; may not be implemented yet)
 
+ SA  308  If-then-else expression                      GvR, Hettinger
  SA  328  Imports: Multi-Line and Absolute/Relative    Aahz
  SA  342  Coroutines via Enhanced Generators           GvR, Eby
  SA  343  Anonymous Block Redux and Generator Enhancements  GvR
@@ -203,7 +204,6 @@ Index by Category
  SR  295  Interpretation of multiline string constants Koltsov
  SR  296  Adding a bytes Object Type                   Gilbert
  SR  303  Extend divmod() for Multiple Divisors        Bellman
- SR  308  If-then-else expression                      GvR, Hettinger
  SR  310  Reliable Acquisition/Release Pairs           Hudson, Moore
  SD  312  Simple Implicit Lambda                       Suzi, Martelli 
  SR  313  Adding Roman Numeral Literals to Python      Meyer
@@ -353,7 +353,7 @@ Numerical Index
  SF  305  CSV File API                                 Montanaro, et al
  I   306  How to Change Python's Grammar               Hudson
  SF  307  Extensions to the pickle protocol            GvR, Peters
- SR  308  If-then-else expression                      GvR, Hettinger
+ SA  308  If-then-else expression                      GvR, Hettinger
  SF  309  Partial Function Application                 Harris
  S   310  Reliable Acquisition/Release Pairs           Hudson, Moore
  SF  311  Simplified GIL Acquisition for Extensions    Hammond

pep-0308.txt

@@ -3,14 +3,43 @@ Title: If-then-else expression
 Version: $Revision$
 Last-Modified: $Date$
 Author: Guido van Rossum, Raymond D. Hettinger
-Status: Rejected
+Status: Accepted
 Type: Standards Track
 Content-Type: text/plain
 Created: 7-Feb-2003
 Post-History: 7-Feb-2003, 11-Feb-2003
 
+Adding a conditional expression
 
-Introduction
+    On 9/29/2005, Guido decided to add conditional expressions in the
+    form of "X if C else Y". [1]
+
+    The motivating use case was the prevalance of error-prone attempts
+    to achieve the same effect using "and" and "or". [2]
+    
+    Previous community efforts to add a conditional expression were
+    stymied by a lack of consensus on the best syntax.  That issue was
+    resolved by simply deferring to a BDFL best judgment call.
+
+    The decision was validated by reviewing the how the syntax fared when
+    applied throughout the standard library (this review approximates a
+    sampling of real-world use cases, across a variety of applications,
+    written by a number of programmers with diverse backgrounds). [3]
+
+References
+
+    [1] Pronouncement
+        http://mail.python.org/pipermail/python-dev/2005-September/056846.html
+
+    [2] Motivating use case:
+        http://mail.python.org/pipermail/python-dev/2005-September/056546.html
+        http://mail.python.org/pipermail/python-dev/2005-September/056510.html        
+
+    [3] Review in the context of real-world code fragments:
+        http://mail.python.org/pipermail/python-dev/2005-September/056803.html
+
+
+Introduction to earlier draft of the PEP (kept for historical purposes)
 
     Requests for an if-then-else ("ternary") expression keep coming up
     on comp.lang.python.  This PEP contains a concrete proposal of a