vim-patch:8.2.1544: cannot translate messages in a Vim script

Problem:    Cannot translate messages in a Vim script.
Solution:   Add gettext().  Try it out for a few messages in the options
            window.

https://github.com/vim/vim/commit/0b39c3fd4c5d1c8ebd2efa85fced7df5e17efd3b

Co-authored-by: Bram Moolenaar <Bram@vim.org>

3 files changed, 22 insertions, 7 deletions

diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index 2c00f755be..8c9c14ffde 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -220,6 +220,7 @@ gettabvar({nr}, {varname} [, {def}])
 gettabwinvar({tabnr}, {winnr}, {name} [, {def}])
 				any	{name} in {winnr} in tab page {tabnr}
 gettagstack([{nr}])		Dict	get the tag stack of window {nr}
+gettext({text})			String	lookup translation of {text}
 getwininfo([{winid}])		List	list of info about each window
 getwinpos([{timeout}])		List	X and Y coord in pixels of the Vim window
 getwinposx()			Number	X coord in pixels of Vim window
@@ -3584,6 +3585,19 @@ gettagstack([{winnr}])					*gettagstack()*
 		Can also be used as a |method|: >
 			GetWinnr()->gettagstack()
 
+
+gettext({text})						*gettext()*
+		Translate {text} if possible.
+		This is mainly for use in the distributed Vim scripts.  When
+		generating message translations the {text} is extracted by
+		xgettext, the translator can add the translated message in the
+		.po file and Vim will lookup the translation when gettext() is
+		called.
+		For {text} double quoted strings are preferred, because
+		xgettext does not understand escaping in single quoted
+		strings.
+
+
 getwininfo([{winid}])					*getwininfo()*
 		Returns information about windows as a |List| with Dictionaries.
 
diff --git a/runtime/doc/usr_41.txt b/runtime/doc/usr_41.txt
index d2db967c97..6d139643d6 100644
--- a/runtime/doc/usr_41.txt
+++ b/runtime/doc/usr_41.txt
@@ -639,6 +639,7 @@ String manipulation:					*string-functions*
 	execute()		execute an Ex command and get the output
 	win_execute()		like execute() but in a specified window
 	trim()			trim characters from a string
+	gettext()		lookup message translation
 
 List manipulation:					*list-functions*
 	get()			get an item without error for wrong index
diff --git a/runtime/optwin.vim b/runtime/optwin.vim
index 4db5e20921..16af8fce17 100644
--- a/runtime/optwin.vim
+++ b/runtime/optwin.vim
@@ -149,13 +149,13 @@ exe $OPTWIN_CMD . ' new option-window'
 setlocal ts=15 tw=0 noro buftype=nofile
 
 " Insert help and a "set" command for each option.
-call append(0, '" Each "set" line shows the current value of an option (on the left).')
-call append(1, '" Hit <CR> on a "set" line to execute it.')
-call append(2, '"            A boolean option will be toggled.')
-call append(3, '"            For other options you can edit the value before hitting <CR>.')
-call append(4, '" Hit <CR> on a help line to open a help window on this option.')
-call append(5, '" Hit <CR> on an index line to jump there.')
-call append(6, '" Hit <Space> on a "set" line to refresh it.')
+call append(0, gettext('" Each "set" line shows the current value of an option (on the left).'))
+call append(1, gettext('" Hit <Enter> on a "set" line to execute it.'))
+call append(2, gettext('"            A boolean option will be toggled.'))
+call append(3, gettext('"            For other options you can edit the value before hitting <Enter>.'))
+call append(4, gettext('" Hit <Enter> on a help line to open a help window on this option.'))
+call append(5, gettext('" Hit <Enter> on an index line to jump there.'))
+call append(6, gettext('" Hit <Space> on a "set" line to refresh it.'))
 
 " These functions are called often below.  Keep them fast!