The purpose of this page is to illustrate the use of the msgcat package to make a Tk software internationalized automatically. The recommended usage of the msgcat package to translate messages is to insert msgcat::mc instructions like this:
Instead of
label .x -text Files
you write
label .x -text [msgcat::mc Files]
This forces the developer to insert "msgcat::mc" everywhere into the current Tcl script. Of course, it is well known that the Frink tool can instrument a Tcl script and insert the msgcat::mc automatically. But the resulting script is modified, which may be unwanted (frink).
What should be available is a method to translate automatically the software, without modification of the original script. The only things which should be done are:
One can try to overload the Tk widgets to use the msgcat::mc automatically. The following is an example. The first call to "tk_chooseDirectory" is untranslated. Then one creates a translation command inside the "mynamespace" namespace. Then the tk_chooseDirectory is overloaded so that the next use of "tk_chooseDirectory" automatically uses the msgcat::mc command with the provided translation command.
package require Tcl
package require Tk
package require msgcat
::msgcat::mclocale fr
set dirname [tk_chooseDirectory -title "This is an untranslated title"]
msgcat::mcset fr "This is an untranslated title" "C'est mon titre"
namespace eval mynamespace {
proc translate { original } {
set translated [msgcat::mc $original]
return $translated
}
}
if {[info commands "::tk_chooseDirectory"]=="::tk_chooseDirectory"} then {
rename ::tk_chooseDirectory ::_tk_chooseDirectory
proc ::tk_chooseDirectory {args} {
set command [list "::_tk_chooseDirectory"]
foreach {key value} $args {
if {$key=="-title" || $key=="-message"} then {
set value [mynamespace::translate $value]
}
lappend command $key $value
}
set answer [eval $command]
return $answer
}
}
set dirname [tk_chooseDirectory -title "This is an untranslated title"]This is interesting, but way too simple to be used in practical applications, mainly because one may want to configure our own translation command. The following is another attempt of what could be done.
package require tkinternat tkinternat::configure -translationcmd "mynamespace::translate" tkinternat::overload "tk_chooseDirectory" tkinternat::overload "button" tkinternat::overload "checkbutton" tkinternat::overload "label" tkinternat::overload "menu" tkinternat::overload "menubutton" tkinternat::overload "labelframe" tkinternat::overload "message" tkinternat::overload "radiobutton"
This would allow to use the command "mynamespace::translate" and, after overloading the Tk widgets, the code can be used translated without modification. Here is the complete example :
package require Tcl
package require Tk
package require msgcat
msgcat::mclocale fr
set dirname [tk_chooseDirectory -title "This is an untranslated title"]
namespace eval mynamespace {
msgcat::mcset fr "This is an untranslated title" "C'est mon titre"
msgcat::mcset fr "Language" "Langue"
msgcat::mcset fr "English" "Anglais"
msgcat::mcset fr "File" "Fichier"
proc translate { original } {
set translated [msgcat::mc $original]
return $translated
}
}
lappend ::auto_path .
package require tkinternat
tkinternat::configure -translationcmd "mynamespace::translate"
tkinternat::overload "tk_chooseDirectory"
tkinternat::overload "button"
tkinternat::overload "checkbutton"
tkinternat::overload "label"
tkinternat::overload "menu"
tkinternat::overload "menubutton"
tkinternat::overload "labelframe"
tkinternat::overload "message"
tkinternat::overload "radiobutton"
set dirname [tk_chooseDirectory -title "This is an untranslated title"]
pack [button .mybutton -text "This is an untranslated title"]
pack [checkbutton .mycheckbutton -text "This is an untranslated title"]
pack [label .mylabel -text "This is an untranslated title"]
pack [labelframe .mylabelframe -text "This is an untranslated title"]
pack [entry .mylabelframe.myentry]
. configure -menu [menu .m -title "This is an untranslated title"]
menu .m.m2 -tearoff 1
# "add" is not overloaded
.m add cascade -label "Language" -menu .m.m2
foreach language {English French German} {
.m.m2 add command -label $language
}
# Test menubutton
frame .myframeBis
pack .myframeBis -side top -fill x -pady 0
menubutton .myframeBis.file -text "File" -menu .myframeBis.file.menu -underline 0
menu .myframeBis.file.menu -tearoff false
pack .myframeBis.file -side left
pack [message .mymessage -text "This is an untranslated title"]
pack [radiobutton .myradiobutton -text "This is an untranslated title"]
wm title . "Test"The application is based on the package "tkinternat" which is the following. It is made with low-level Tcl, but it works !
package provide tkinternat 1.0
namespace eval tkinternat {
variable _translatecmd ""
}
proc tkinternat::configure { args } {
foreach { key value } $args {
switch -- $key {
"-translationcmd" {
set tkinternat::_translatecmd $value
}
default {
error "Unknown option $key."
}
}
}
return ""
}
proc tkinternat::cget { key } {
switch -- $key {
"-translationcmd" {
set value $tkinternat::_translatecmd
}
default {
error "Unknown option $key."
}
}
return $value
}
proc tkinternat::overload { tkwidget } {
switch -- $tkwidget {
"tk_getOpenFile" -
"tk_getSaveFile" -
"tk_chooseColor" -
"tk_messageBox" -
"tk_chooseDirectory" {
if {[info commands "::$tkwidget"]=="::$tkwidget"} then {
rename ::$tkwidget ::_$tkwidget
set script "proc ::$tkwidget { args } { \n"
append script "set command \[list ::_$tkwidget\]\n"
append script "foreach {key value} \$args {\n"
append script "if {\$key==\"-title\" || \$key==\"-message\" || \$key==\"-text\"} then {\n"
append script "set translatecmd \[tkinternat::cget -translationcmd\]\n"
append script "set value \[eval \[list \$translatecmd \$value\]\]\n"
append script "}\n"
append script "lappend command \$key \$value\n"
append script "}\n"
append script "set answer \[eval \$command\]\n"
append script "return \$answer\n"
append script "}"
eval $script
}
}
"button" -
"checkbutton" -
"menu" -
"menubutton" -
"message" -
"radiobutton" -
"label" -
"labelframe" {
if {[info commands "::$tkwidget"]=="::$tkwidget"} then {
rename ::$tkwidget ::_$tkwidget
set script "proc ::$tkwidget { pathname args } { \n"
append script "set command \[list ::_$tkwidget \$pathname\]\n"
append script "foreach {key value} \$args {\n"
append script "if {\$key==\"-title\" || \$key==\"-text\" || \$key==\"-label\"} then {\n"
append script "set translatecmd \[tkinternat::cget -translationcmd\]\n"
append script "set value \[eval \[list \$translatecmd \$value\]\]\n"
append script "}\n"
append script "lappend command \$key \$value\n"
append script "}\n"
append script "puts \"command : \$command\"\n"
append script "set answer \[eval \$command\]\n"
append script "return \$answer\n"
append script "}"
eval $script
}
}
default {
error "Unknown tkwidget $tkwidget"
}
}
}See also: