Can't do a multiline assignment!

[J. Cliff Dyer]

On Thu, 2008-04-17 at 13:53 -0400, Steve Holden wrote:
> Gary Herron wrote:
> > s0suk3 at gmail.com wrote:
> >> On Apr 17, 10:54 am, colas.fran... at gmail.com wrote:
> >>   
> >>> On 17 avr, 17:40, s0s... at gmail.com wrote:
> >>>
> >>> Out of sheer curiosity, why do you need thirty (hand-specified and
> >>> dutifully commented) names to the same constant object if you know
> >>> there will always be only one object?
> >>>     
> >> I'm building a web server. The many variables are names of header
> >> fields. One part of the code looks like this (or at least I'd like it
> >> to):
> >>
> >> class RequestHeadersManager:
> >>
> >>     # General header fields
> >>     Cache_Control               = \
> >>     Connection                  = \
> >>     Date                        = \
> >>     Pragma                      = \
> >>     Trailer                     = \
> >>     Transfer_Encoding           = \
> >>     Upgrade                     = \
> >>     Via                         = \
> >>     Warning                     = \
> >>
> >>     # Request header fields
> >>     Accept                      = \
> >>     Accept_Charset              = \
> >>     Accept_Encoding             = \
> >>     Accept_Language             = \
> >>     Authorization               = \
> >> ...
> >>   
> > 
> > But.  *What's the point* of doing it this way.    I see 14 variables 
> > being assigned a value, but I don't see the value, they are getting.   
> > Reading this bit if code provides no useful information unless I'm 
> > willing to scan down the file until I find the end of this mess.  And in 
> > that scanning I have to make sure I don't miss the one single line that 
> > does not end in a backslash.    (Your ellipsis conveniently left out the 
> > *one* important line needed to understand what this code is doing,  but 
> > even if you had included it, I'd have to scan *all* lines to understand 
> > what a single value is being assigned.
> > 
> > There is *no way* you can argue that code is clearer than this:
> > 
> >     # General header fields
> >     Cache_Control               = None
> >     Connection                  = None
> >     Date                        = None
> >     Pragma                      = None
> > ...
> > 
> Thank you, you saved me from making that point. It doesn't even seem 
> like there's a need for each header to reference the same value (though 
> in this case they will, precisely because there is only one None object).
> 
> regards
>   Steve

Another possibility is to assign to a dict using a loop, if typing None
over and over again is so onerous.

options = ['cache_control', 
           'connection', 
           'date', 
           'pragma']
params = {}

for option in options:
    params[option] = None

And of course you could substitute your choice of appropriate __dict__
for params, if you want to access the options as free-standing objects.

Cheers,
Cliff