added PEP 313, Adding Roman Numeral Literals to Python, by Mike Meyer

pep-0000.txt

@@ -114,6 +114,7 @@ Index by Category
  S   310  Reliable Acquisition/Release Pairs           Hudson, Moore
  S   311  Simplified GIL Acquisition for Extensions    Hammond
  S   312  Simple Implicit Lambda                       Suzi, Martelli
+ S   313  Adding Roman Numeral Literals to Python      Meyer
 
  Finished PEPs (done, implemented in CVS)
 
@@ -316,6 +317,7 @@ Numerical Index
  S   310  Reliable Acquisition/Release Pairs           Hudson, Moore
  S   311  Simplified GIL Acquisition for Extensions    Hammond
  S   312  Simple Implicit Lambda                       Suzi, Martelli
+ S   313  Adding Roman Numeral Literals to Python      Meyer
  SR  666  Reject Foolish Indentation                   Creighton
 
 
@@ -375,6 +377,7 @@ Owners
     McMillan, Gordon         gmcm@hypernet.com
     McNamara, Andrew         andrewm@object-craft.com.au
     Mick, Trent              trentm@activestate.com
+    Meyer, Mike              mwm@mired.org
     Montanaro, Skip          skip@pobox.com
     Moore, Paul              gustav@morpheus.demon.co.uk
     Norwitz, Neal            neal@metaslash.com

pep-0313.txt

@@ -0,0 +1,115 @@
+PEP: 313
+Title: Adding Roman Numeral Literals to Python
+Version: $Revision $
+Last-Modified: $Date $
+Author: Mike Meyer <mwm@mired.org>
+Status: Draft
+Type: Standards Track
+Content-Type: text/plain
+Created: 01-Apr-2003
+Python-Version: 2.4
+Post-History:
+
+
+Abstract
+
+    This PEP proposes adding Roman numerals as a literal type.  It
+    also proposes the new built-in function "roman", which converts an
+    object to an integer, then converts the integer to a string that
+    is the Roman numeral literal equivalent to the integer.
+
+
+Rationale
+
+    Roman numerals are used in a number of areas, and adding them to
+    Python as literals would make computations in those areas easier.
+    For instance, Superbowls are counted with Roman numerals, and many
+    older movies have copyright dates in Roman numerals.  Further,
+    LISP provides a Roman numerals literal package, so adding Roman
+    numerals to Python will help ease the LISP-envy sometimes seen in
+    comp.lang.python.  Besides, the author thinks this is the easiest
+    way to get his name on a PEP.
+
+
+Syntax for Roman literals
+
+    Roman numeral literals will consist of the characters M, D, C, L,
+    X, V and I, and only those characters.  They must be in upper
+    case, and represent an integer with the following rules:
+
+    1.  Except as noted below, they must appear in the order M, D, C,
+    L, X, V then I.  Each occurence of each character adds 1000, 500,
+    100, 50, 10, 5 and 1 to the value of the literal, respectively.
+
+    2.  Only one D, V or L may appear in any given literal.
+
+    3.  At most three Is, Xs and Cs may appear in any given literal.
+
+    4.  A single I may appear immediately to the left of the single V,
+    followed by no Is, and adds 4 to the value of the literal.
+
+    5.  A single I may likewise appear before the last X, followed by
+    no Is or Vs, and adds 9 to the value.
+
+    6.  X is to L and C as I is to V and X, except the values are 40
+    and 90, respectively.
+
+    7.  C is to D and M as I is to V and X, except the values are 400
+    and 900, respectively.
+
+    Any literal composed entirely of M, D, C, L, X, V and I characters
+    that does not follow this format will raise a syntax error,
+    because explicit is better than implicit.
+
+
+Builtin "roman" Function
+
+    The new builtin function "roman" will aide the translation from
+    integers to Roman numeral literals.  It will accept a single
+    object as an argument, and return a string containing the literal
+    of the same value.  If the argument is not an integer or a
+    rational (see PEP 239 [1]) it will passed through the existing
+    builtin "int" to obtain the value.  This may cause a loss of
+    information if the object was a float.  If the object is a
+    rational, then the result will be formatted as a rational literal
+    (see PEP 240 [2]) with the integers in the string being Roman
+    numeral literals.
+
+
+Compatability Issues
+
+    No new keywords are introduced by this proposal.  Programs that
+    use variable names that are all upper case and contain only the
+    characters M, D, C, L, X, V and I will be affected by the new
+    literals.  These programs will now have syntax errors when those
+    variables are assigned, and either syntax errors or subtle bugs
+    when those variables are referenced in expressions.  Since such
+    variable names violate PEP 8 [3], the code is already broken, it
+    just wasn't generating exceptions. This proposal corrects that
+    oversight in the language.
+
+
+References
+
+    [1] PEP 239, Adding a Rational Type to Python
+        http://www.python.org/peps/pep-0239.html
+
+    [2] PEP 240, Adding a Rational Literal to Python
+        http://www.python.org/peps/pep-0240.html
+
+    [3] PEP 8, Style Guide for Python Code
+        http://www.python.org/peps/pep-0008.html
+
+
+Copyright
+
+    This document has been placed in the public domain.
+
+
+^L
+Local Variables:
+mode: indented-text
+indent-tabs-mode: nil
+sentence-end-double-space: t
+fill-column: 70
+End: