Re: [PATCH v2 03/11] i18n: add--interactive: mark strings with interpolation for translation

["Jakub Narębski" <jnareb@gmail.com>]

W dniu 31.08.2016 o 14:31, Vasco Almeida pisze:

> Use of sprintf following die or error_msg is necessary for placeholder
> substitution take place.

No, it is not.  Though I don't think that we have in out Git::I18N
the support for Perl i18n placeholder substitution.

From gettext manual:
https://www.gnu.org/software/gettext/manual/gettext.html#perl_002dformat

  15.3.16 Perl Format Strings

  There are two kinds format strings in Perl: those acceptable to the Perl
  built-in function printf, labelled as ‘perl-format’, and those acceptable
  to the libintl-perl function __x, labelled as ‘perl-brace-format’.

  Perl printf format strings are described in the sprintf section of
  ‘man perlfunc’.

  Perl brace format strings are described in the Locale::TextDomain(3pm)
  manual page of the CPAN package libintl-perl. In brief, Perl format uses
  placeholders put between braces (‘{’ and ‘}’). The placeholder must have
  the syntax of simple identifiers.
 
Git doesn't use Locale::TextDomain, from what I understand, to provide
fallback in no-gettext case.  Also, Locale::TextDomain is not in core.

The syntax, with the help of shorthand helper function, looks like this:
http://search.cpan.org/dist/libintl-perl/lib/Locale/TextDomain.pm#EXPORTED_FUNCTIONS
https://metacpan.org/pod/Locale::TextDomain#EXPORTED-FUNCTIONS

  __x MSGID, ID1 => VAL1, ID2 => VAL2, ...
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  One of the nicest features in Perl is its capability to interpolate
  variables into strings:

    print "This is the $color $thing.\n";

  This nice feature might con you into thinking that you could now write

    print __"This is the $color $thing.\n";

  [But this doesn't work...]

  [...] The Perl backend to GNU gettext has defined an alternative format
  [to using printf / sprintf] for interpolatable strings:

    "This is the {color} {thing}.\n";

  Instead of Perl variables you use place-holders (legal Perl variables
  are also legal place-holders) in curly braces, and then you call

    print __x ("This is the {color} {thing}.\n", 
               thing => $thang,
               color => $color);

> Signed-off-by: Vasco Almeida <vascomalmeida@sapo.pt>
> ---
>  git-add--interactive.perl | 26 ++++++++++++++------------
>  1 file changed, 14 insertions(+), 12 deletions(-)
> 
> diff --git a/git-add--interactive.perl b/git-add--interactive.perl
> index e11a33d..4e1e857 100755
> --- a/git-add--interactive.perl
> +++ b/git-add--interactive.perl
> @@ -612,12 +612,12 @@ sub list_and_choose {
>  			else {
>  				$bottom = $top = find_unique($choice, @stuff);
>  				if (!defined $bottom) {
> -					error_msg "Huh ($choice)?\n";
> +					error_msg sprintf(__("Huh (%s)?\n"), $choice);

So this would be, self explained without need of comment
for translators:

  +					error_msg __x ("Huh ({choice})?\n"), choice => $choice);


>  					next TOPLOOP;
>  				}

Though this is probably more work that you wanted to do.
The __x might be defined like this (borrowing from Locale::TextDomain),
which needs to be put into perl/Git/I18N.pm

  sub __ ($);
  sub __expand ($%);

  # With interpolation.
  sub __x ($@)
  {
  	my ($msgid, %vars) = @_;

  	return __expand (__($msgid), %vars);
  }
  
  sub __expand ($%)
  {
  	my ($translation, %args) = @_;
    
  	my $re = join '|', map { quotemeta $_ } keys %args;
  	$translation =~ s/\{($re)\}/defined $args{$1} ? $args{$1} : "{$1}"/ge;

  	return $translation;
  }



Best regards,
-- 
Jakub Narębski