[Development] QLocale work

[John Layt]

On Sunday 15 Jan 2012 19:04:09 John Layt wrote:

> I think I'm favouring the second option as being cleaner and easier to
> implement in phases.

After reading more of the ICU number API and trying some things out, I now 
think sticking closer to the current model will actually match the ICU API 
better and require less code albeit in one big bang.

* QLocalePrivate holds instances of the ICU Locale, NumberFormat, DateFormat 
etc classes.  QLocale methods call these objects directly to obtain format 
codes and perform format/parse without any call to QSystemLocale.

* For Named locales, i.e. app creates QLocale instance for en_GB: 
QLocalePrivate is created, ICU Locale and format classes initialised.  All 
QLocale calls will thus use only the CLDR default settings for the named 
locale.

* For System locale, i.e. app creates default QLocale instance: QLocalePrivate 
created as per Named locales, but then calls QSystemLocale to obtain all the 
settings which are used to set the ICU NumberFormat and DateFormat default 
values.  All QLocale calls will thus pickup the system settings.

* A QCldrLocale is not really needed for Qt purposes, it's only needed for 
anyone who wants to know what individual settings are, like KDE.

Note the ICU Format class instances may have delayed initialisation for 
efficiency, i.e. only when toString() is called for the first time.

Cheers!

John.