From: Anders Kaseorg <andersk@mit.edu>
Date: Mon, 30 May 2011 03:05:29 GMT
Subject: Re: [PATCH 3/3] gitk: Allow displaying time zones from author and commit timestamps
Message-ID: <alpine.DEB.2.02.1105291740410.23145@dr-wily.mit.edu>
In-Reply-To: <20110529044656.GA8881@brick.ozlabs.ibm.com>

On Sun, 29 May 2011, Paul Mackerras wrote:
> > @@ -11018,7 +11018,18 @@ proc prefsok {} {
> >  proc formatdate {d} {
> >      global datetimeformat
> >      if {$d ne {}} {
> > -	set d [clock format [lindex $d 0] -format $datetimeformat]
> > +	if {[string match {*%[zZ]*} $datetimeformat]} {
> > +	    if {[catch {set d [clock format [lindex $d 0] -timezone [lindex $d 1] -format $datetimeformat]}]} {
> > +		# Tcl < 8.5 does not support -timezone.
> > +		global env
> > +		set zone [lindex $d 1]
> > +		set env(TZ) "IDK[string range $zone 0 2]:[string range $zone 3 end]"
> 
> What is this about?  Where is the IDK prefix for timezones defined or
> described?

Yeah, sorry, that deserved a bit more explanation.  This is a kludge to 
get Tcl 8.4 to format dates in the right timezone.  IDK is an arbitrary 
made up 3-letter code (“I Don’t Know”), since a UTC offset can’t generally 
be converted into a zone name.  The format of TZ is described at:
http://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html
http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html

Actually, reading that again, I just realized that I need to invert the 
sign.  Also that it can be longer than 3 letters; I’ll use “Unknown” 
instead.

> > +		set d [clock format [lindex $d 0] -format $datetimeformat]
> > +		unset env(TZ)
> 
> Oops, we just lost any previous setting of TZ...

Good point.

Thanks for taking a look.  I’ll follow up with a fixed version.

Anders