PEP 260: simplify xrange()

pep-0000.txt

@@ -60,6 +60,7 @@ Index by Category
  S   256  pep-0256.txt  Docstring Processing System Framework  Goodger
  S   257  pep-0257.txt  Docstring Conventions               Goodger, van Rossum
  S   258  pep-0258.txt  DPS Generic Implementation Details     Goodger
+ S   260  pep-0260.txt  Simplify xrange()                      van Rossum
 
  Py-in-the-sky PEPs (not ready; may become active yet)
 
@@ -186,6 +187,7 @@ Numerical Index
  S   257  pep-0257.txt  Docstring Conventions               Goodger, van Rossum
  S   258  pep-0258.txt  DPS Generic Implementation Details     Goodger
  SR  259  pep-0259.txt  Omit printing newline after newline    van Rossum
+ S   260  pep-0260.txt  Simplify xrange()                      van Rossum
 
 
 Key

pep-0260.txt

@@ -0,0 +1,75 @@
+PEP: 260
+Title: Simplify xrange()
+Version: $Revision$
+Author: guido@python.org (Guido van Rossum)
+Status: Draft
+Type: Standards Track
+Python-Version: 2.2
+Created: 26-Jun-2001
+Post-History: 26-Jun-2001
+
+Abstract
+
+    This PEP proposes to strip the xrange() object from some rarely
+    used behavior like x[i:j] and x*n.
+
+
+Problem
+
+    The xrange() function has one idiomatic use:
+
+        for i in xrange(...): ...
+
+    However, the xrange() object has a bunch of rarely used behaviors
+    that attempt to make it more sequence-like.  These are so rarely
+    used that historically they have has serious bugs (e.g. off-by-one
+    errors) that went undetected for several releases.
+
+    I claim that it's better to drop these unused features.  This will
+    simplify the implementation, testing, and documentation, and
+    reduce maintenance and code size.
+
+
+Proposed Solution
+
+    I propose to strip the xrange() object to the bare minimum.  The
+    only retained sequence behaviors are x[i], len(x), and repr(x).
+    In particular, these behaviors will be dropped:
+
+        x[i:j] (slicing)
+        x*n, n*x (sequence-repeat)
+        cmp(x1, x2) (comparisons)
+	i in x (containment test)
+        x.tolist() method
+        x.start, x.stop, x.step attributes
+
+    By implementing a custom iterator type, we could speed up the
+    common use, but this is optional (the default sequence iterator
+    does just fine).
+
+    I expect it will take at most an hour to rip it all out; another
+    hour to reduce the test suite and documentation.
+
+
+Scope
+
+    This PEP only affects the xrange() built-in function.
+
+
+Risks
+
+    Somebody's code could be relying on the extended code, and this
+    code would break.  However, given that historically bugs in the
+    extended code have gone undetected for so long, it's unlikely that
+    much code is affected.
+
+
+Copyright
+
+    This document has been placed in the public domain.
+
+
+Local Variables:
+mode: indented-text
+indent-tabs-mode: nil
+End: