[Python-3000] Move argv[0]? (Re: Unicode and OS strings)

[Larry Hastings]

Guido van Rossum wrote:
> On 9/15/07, Greg Ewing <greg.ewing at canterbury.ac.nz> wrote:
>   
>> Changing the existing behaviour of argv would probably
>> be too disruptive, so how about relegating argv to a
>> low-level detail and providing something else for
>> everyday use that omits argv[0]?
>>
>> sys.arguments would sound quite nice for that.
> This sounds awfully close to bikeshedding. Change too many details
> like this and you cause death by a 1000 pinpricks for existing apps.
> sys.argv[0] *does* get used (though arguably rarely in the same way as
> sys.argv[1:]).

+0.5 on Greg Ewing's proposal.

argv[0] has little in common with argv[1:]; why should the user have to 
differentiate them?  I see this as yet one more messy detail of the OS 
that Python could hide for me.  Looking at it with fresh eyes, I think
    for a in sys.arguments:
is a lot prettier than
    for a in sys.argv[1:]:
After all: what's that 1: doing there?  Why the magic number?  Why does 
argv have the script name in [0], anyway?  None of my other 
functions/members are forced to take themselves as their first argument.

Taking it to its logical conclusion, I further propose:
    sys.raw_argv -- the original bytes as they came in from from the OS
    sys.argv -- raw_argv converted into (unicode) strings, not expected 
to be used by users
    sys.arguments -- sys.argv[1:]
    sys.script_path -- sys.argv[0]
    sys.split_argv -- callable that takes an argv-style array (strings, 
not bytes) and assigns it into argv, arguments, and script_path, slicing 
as appropriate

Yes, the format of argv has thirty years of history; yes I don't really 
expect this discussion to get anywhere.  But I hate having arbitrary 
idioms in Python, and I wanted to cast my vote into the swirling void 
before this idea totally died.

If nothing else, at least we could fix the proviso for argv[0]: "(it is 
operating system dependent whether this is a full pathname or not)."  
How about we always ensure it is an absolute path?


My "there's only one way to do it" reflex is fighting it out with my 
"beautiful is better than ugly" reflex,


/larry/
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