Tcl Source Code

.sp
.VS "TIP 490"
\fB::msgcat::mcpackagenamespaceget\fR
.VE "TIP 490"
.sp
\fB::msgcat::mclocale \fR?\fInewLocale\fR?
.sp
.VS "TIP 499"
\fB::msgcat::mcpreferences\fR ?\fIlocale preference\fR? ...
.VE "TIP 499"
.sp
.VS "TIP 412"
\fB::msgcat::mcloadedlocales subcommand\fR ?\fIlocale\fR?
.VE "TIP 412"
.sp
\fB::msgcat::mcload \fIdirname\fR
.sp

.VS "TIP 412"
\fB::msgcat::mcpackagelocale subcommand\fR ?\fIlocale\fR?
.sp
\fB::msgcat::mcpackageconfig subcommand\fR \fIoption\fR ?\fIvalue\fR?
.sp
\fB::msgcat::mcforgetpackage\fR
.VE "TIP 412"
.sp
.VS "TIP 499"
\fB::msgcat::mcutil subcommand\fR ?\fIlocale\fR?
.VS "TIP 499"
.BE
.SH DESCRIPTION
.PP
The \fBmsgcat\fR package provides a set of functions
that can be used to manage multi-lingual user interfaces.
Text strings are defined in a
.QW "message catalog"

.PP
.VE "TIP 490"
.VS "TIP 490"
.TP
\fB::msgcat::mcpackagenamespaceget\fR
.
Return the package namespace of the caller.
This command handles all cases described in section \fBOBJECT ORIENTED PROGRAMMING\fR.
.PP
.RS
Example usage is a tooltip package, which saves the caller package namespace to update the translation each time the tooltip is shown:
.CS
proc ::tooltip::tooltip {widget message} {
    ...
    set messagenamespace [uplevel 1 {::msgcat::mcpackagenamespaceget}]

.CE
.RE
.PP
.VE "TIP 490"
.TP
\fB::msgcat::mclocale \fR?\fInewLocale\fR?
.

If \fInewLocale\fR is omitted, the current locale is returned, otherwise the current locale
is set to \fInewLocale\fR.
.PP
.RS
If the new locale is set to \fInewLocale\fR, the corresponding preferences are calculated and set.
For example, if the current locale is en_US_funky, then \fB::msgcat::mcpreferences\fR returns \fB{en_us_funky en_us en {}}\fR.
.PP
The same result may be acheved by \fB::msgcat::mcpreferences\fR {*}[\fB::msgcat::mcutil getpreferences\fR \fInewLocale\fR].
.PP
The current locale is always the first element of the list returned by \fBmcpreferences\fR.
.PP
msgcat stores and compares the locale in a
case-insensitive manner, and returns locales in lowercase.
The initial locale is determined by the locale specified in
the user's environment.  See \fBLOCALE SPECIFICATION\fR
below for a description of the locale string format.

.PP
.VS "TIP 412"
If the locale is set, the preference list of locales is evaluated.
Locales in this list are loaded now, if not jet loaded.
.VE "TIP 412"
.RE
.TP
\fB::msgcat::mcpreferences\fR ?\fIlocale preference\fR? ...
.
Without arguments, returns an ordered list of the locales preferred by
the user.
The list is ordered from most specific to least preference.
.PP
.VS "TIP 499"
.RS
A set of locale preferences may be given to set the list of locale preferences.
The current locale is also set, which is the first element of the locale preferences list.
.PP
Locale preferences are loaded now, if not jet loaded.
.PP
As an example, the user may prefer French or English text. This may be configured by:
.CS
::msgcat::mcpreferences fr en {}

.CE
.RE
.PP
.VS "TIP 499"
.TP
\fB::msgcat:mcloadedlocales subcommand\fR ?\fIlocale\fR?
.
This group of commands manage the list of loaded locales for packages not setting a package locale.
.PP
.RS
The subcommand \fBget\fR returns the list of currently loaded locales.

Note that this routine is only called if the concerned package did not set a package locale unknown command name.
.RE
.TP
\fB::msgcat::mcforgetpackage\fR
.
The calling package clears all its state within the \fBmsgcat\fR package including all settings and translations.
.VE "TIP 412"
.PP
.VS "TIP 499"
.TP
\fB::msgcat::mcutil getpreferences\fR \fIlocale\fR
.
Return the preferences list of the given locale as described in section \fBLOCALE SPECIFICATION\fR.
An example is the composition of a preference list for the bilingual region "Biel/Bienne" as a concatenation of swiss german and swiss french:
.CS
% concat [lrange [msgcat::mcutil getpreferences fr_CH] 0 end-1] [msgcat::mcutil getpreferences de_CH]
fr_ch fr de_ch de {}
.CE
.TP
\fB::msgcat::mcutil getsystemlocale\fR
.
The system locale is returned as described by the section \fBLOCALE SPECIFICATION\fR.
.VE "TIP 499"
.PP
.SH "LOCALE SPECIFICATION"
.PP
The locale is specified to \fBmsgcat\fR by a locale string
passed to \fB::msgcat::mclocale\fR.
The locale string consists of
a language code, an optional country code, and an optional

.PP
.CS
\fBmsgcat::mc\fR {Produced %1$d at %2$s} $num $city
# ... where that key is mapped to one of the
# human-oriented versions by \fBmsgcat::mcset\fR
.CE
.VS "TIP 412"
.SH "PACKAGE PRIVATE LOCALE"
.PP
A package using \fBmsgcat\fR may choose to use its own package private
locale and its own set of loaded locales, independent to the global
locale set by \fB::msgcat::mclocale\fR.
.PP
This allows a package to change its locale without causing any locales load or removal in other packages and not to invoke the global locale change callback (see below).
.PP

This command may cause the load of locales.
.RE
.TP
\fB::msgcat::mcpackagelocale get\fR
.
Return the package private locale or the global locale, if no package private locale is set.
.TP
\fB::msgcat::mcpackagelocale preferences\fR ?\fIlocale preference\fR? ...
.
With no parameters, return the package private preferences or the global preferences,
if no package private locale is set.
The package locale state (set or not) is not changed (in contrast to the command \fB::msgcat::mcpackagelocale set\fR).
.PP
.RS
.VS "TIP 499"
If a set of locale preferences is given, it is set as package locale preference list.
The package locale is set to the first element of the preference list.
A package locale is activated, if it was not set so far.
.PP
Locale preferences are loaded now for the package, if not jet loaded.
.VE "TIP 499"
.RE
.PP
.TP
\fB::msgcat::mcpackagelocale loaded\fR
.
Return the list of locales loaded for this package.
.TP
\fB::msgcat::mcpackagelocale isset\fR
.

.
Returns true, if the given locale is loaded for the package.
.TP
\fB::msgcat::mcpackagelocale clear\fR
.
Clear any loaded locales of the package not present in the package preferences.
.PP
.SH "CHANGING PACKAGE OPTIONS"
.PP
Each package using msgcat has a set of options within \fBmsgcat\fR.
The package options are described in the next sectionPackage options.
Each package option may be set or unset individually using the following ensemble:
.TP
\fB::msgcat::mcpackageconfig get\fR \fIoption\fR
.

The called procedure must return the formatted message which will finally be returned by msgcat::mc.
.PP
A generic unknown handler is used if set to the empty string. This consists in returning the key if no arguments are given. With given arguments, format is used to process the arguments.
.PP
See section \fBcallback invocation\fR below.
The appended arguments are identical to \fB::msgcat::mcunknown\fR.
.RE
.SH "Callback invocation"
A package may decide to register one or multiple callbacks, as described above.
.PP
Callbacks are invoked, if:
.PP
1. the callback command is set,
.PP
2. the command is not the empty string,
.PP
3. the registering namespace exists.
.PP
If a called routine fails with an error, the \fBbgerror\fR routine for the interpreter is invoked after command completion.
Only exception is the callback \fBunknowncmd\fR, where an error causes the invoking \fBmc\fR-command to fail with that error.
.PP
.VS tip490
.SH "OBJECT ORIENTED PROGRAMMING"
\fBmsgcat\fR supports packages implemented by object oriented programming.
Objects and classes should be defined within a package namespace.
.PP
There are 3 supported cases where package namespace sensitive commands of msgcat (\fBmc\fR, \fBmcexists\fR, \fBmcpackagelocale\fR, \fBmcforgetpackage\fR, \fBmcpackagenamespaceget\fR, \fBmcpackageconfig\fR, \fBmcset\fR and \fBmcmset\fR) may be called:
.PP
.TP
\fB1) In class definition script\fR
.
\fBmsgcat\fR command is called within a class definition script.
.CS
namespace eval ::N2 {
    mcload $dir/msgs
    oo::class create C1 {puts [mc Hi!]}
}
.CE
.PP
.TP
\fB2) method defined in a class\fR
.
\fBmsgcat\fR command is called from a method in an object and the method is defined in a class.
.CS
namespace eval ::N3Class {
    mcload $dir/msgs
    oo::class create C1
    oo::define C1 method m1 {
        puts [mc Hi!]
    }
}
.CE
.PP
.TP
\fB3) method defined in a classless object\fR
.
\fBmsgcat\fR command is called from a method of a classless object.
.CS
namespace eval ::N4 {
    mcload $dir/msgs
    oo::object create O1
    oo::objdefine O1 method m1 {} {
        puts [mc Hi!]
    }
}
.CE
.PP
.VE tip490
.SH EXAMPLES
Packages which display a GUI may update their widgets when the global locale changes.
To register to a callback, use:
.CS
namespace eval gui {
    msgcat::mcpackageconfig changecmd updateGUI

    proc updateGui args {

}
.CE
.VE "TIP 412"
.SH CREDITS
.PP
The message catalog code was developed by Mark Harrison.
.SH "SEE ALSO"
format(n), scan(n), namespace(n), package(n), oo::class(n), oo::object
.SH KEYWORDS
internationalization, i18n, localization, l10n, message, text, translation, class, object
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