ethical questions about global variables

Giampaolo Rodola' gnewsg at gmail.com
Tue Dec 16 19:36:45 CET 2008


On 16 Dic, 18:01, ianaré <ian... at gmail.com> wrote:
> For anything more complicated than a simple script, I find it easier
> to use some sort of config object. This could be a simple dictionnary
> type class, where the values can be set/retrieved by the other classes
> directly, or a more elaborate class including functions to set/
> retrieve the variables. This way setting/retrieving can be 'smart' --
> possibly looking at other variables, program states, thread count,
> whatever, for the requested config option. It also allows for a lot of
> expansion down the line if need be, rather than dealing with all sorts
> of global variables floating around - which gets annoying pretty
> quickly.
>
> On Dec 15, 9:45 pm, "Giampaolo Rodola'" <gne... at gmail.com> wrote:
>
>
>
> > Hi,
> > in a module of mine (ftpserver.py) I'd want to add a (boolean) global
> > variable named "use_gmt_times" to decide whether the server has to
> > return times in GMT or localtime but I'm not sure if it is a good idea
> > because of the "ethical" doubts I'm gonna write below.
>
> > In first place I've never liked global variables too much and always
> > preferred per-class-instance variables instead.
> > The problem in my case is that I have to use such variable in two
> > separated classes: FTPHandler and VirtualFileSystem. Also, I want that
> > for no reason one class uses times in GMT and the other one local
> > times.
>
> > Another doubt is the naming convention. PEP-8 states that global
> > variables should use the lower_case_naming_convention but I've seen a
> > lot of library module using the UPPER_CASE_NAMING_CONVENTION. What am
> > I supposed to do about it?
>
> > Thanks in advance for any comment.
>
> > --- Giampaolohttp://code.google.com/p/pyftpdlib/- Nascondi testo citato
>
> - Mostra testo citato -

All the modificable options the library has acquired so far consist of
class attributes and I'm ok with that.
The only option that should be global is "use_gmt_times" because it is
supposed to be used in two classes and I want that both of them use
the same parameter.
Using a Config class for a single option like "use_gmt_times" is not
worth the effort, IMO.


--- Giampaolo
http://code.google.com/p/pyftpdlib/



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