From maxm at mxm.dk  Wed Mar 15 21:09:19 2006
From: maxm at mxm.dk (Max M)
Date: Wed Mar 15 21:08:46 2006
Subject: [icalendar-checkins] r19617 - in iCalendar/trunk: doc
	src/icalendar
In-Reply-To: <20051107204202.A7A5327B4E@code1.codespeak.net>
References: <20051107204202.A7A5327B4E@code1.codespeak.net>
Message-ID: <4418746F.7070405@mxm.dk>

dreamcatcher@codespeak.net wrote:

>Author: dreamcatcher
>Date: Mon Nov  7 21:41:55 2005
>New Revision: 19617
>
>- Changed UTC tzinfo to a singleton so the same one is used everywhere
>  
>

Hi Sidney,

I find the above behaviour confusing.

The problem is the difference here: "FixedOffset()", "LocalTimezone()", 
"UTC".

Two timezones are classes and a single one is an object.

You changed UTC from a class to an object to make a singleton out of it. 
Why was that necessary? Do you use it for equality comparison somewhere?

If it is only for a minor speedup, I think that will be offset by 
programmers spending time figuring out the difference.

In that case I would have found it better if you made an instance an 
called it "utc" or something like that.


class UTC(tzinfo):

    """UTC tzinfo subclass"""

    def utcoffset(self, dt):
        return ZERO

    def tzname(self, dt):
        return "UTC"

    def dst(self, dt):
        return ZERO

utc = UTC() # singleton


Is there any major complaints if i change it to that?

It *is* only a 0.11 version, so backwards incompatible changes should be ok.

The fix is also easy for packages using it.

from icalendar import utc as UTC


A backwards compatible fix would be to add a call method to the class:

    def __call__(self):
        "FixedOffset and LocalTimezone are both classes."
        pass

But that feels a bit hackish.

-- 

hilsen/regards Max M, Denmark

http://www.mxm.dk/
IT's Mad Science

Phone:  +45 66 11 84 94
Mobile: +45 29 93 42 96