PEP 238 (revised)

Peter Hansen peter at
Thu Jul 26 20:20:37 EDT 2001

Guido van Rossum wrote:
> Here's a completely revised version of PEP 238.  
> Command Line Option
>     The -D command line option takes a string argument that can take
>     three values: "old", "warn", or "new".  The default is "old" in
>     Python 2.2 but will change to "warn" in later 2.x versions.  The
>     "old" value means the classic division operator acts as described.
>     The "warn" value means the classic division operator issues a
>     warning (a DeprecatinWarning using the standard warning framework)
>     when applied to ints or longs.  The "new" value changes the
>     default globally so that the / operator is always interpreted as
>     true division.  

The choice of command line options is inconsistent with the terminology
used elsewhere in the updated PEP.  

To further reduce the potential for confusion, I suggest changing
"old" and "new" to "classic" and "true".  

If that suggestion is accepted, "warn" might be better spelled 
more like "classic-warn".


The updated PEP also makes no mention of a utility for scanning 
existing code to check for potential problems.  Is this considered
an intractable problem?  Is there any commitment to doing this,
eventually, as part of the implementation of this PEP?  Or is the
presence of the "warn" option considered sufficient (to allow for
testing, rather than scanning)?

Peter Hansen, P.Eng.
peter at

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