| Log::Report::Message(3pm) | User Contributed Perl Documentation | Log::Report::Message(3pm) |
Log::Report::Message - a piece of text to be translated
Log::Report::Message is extended by Dancer2::Plugin::LogReport::Message
# Objects created by Log::Report's __ functions
# Full feature description in the DETAILS section
# no interpolation
__"Hello, World";
# with interpolation
__x"age {years}", years => 12;
# interpolation for one or many
my $nr_files = @files;
__nx"one file", "{_count} files", $nr_files;
__nx"one file", "{_count} files", \@files;
# interpolation of arrays
__x"price-list: {prices%.2f}", prices => \@prices, _join => ', ';
# white-spacing on msgid preserved
print __"\tCongratulations,\n";
print "\t", __("Congratulations,"), "\n"; # same
Any use of a translation function exported by Log::Report, like "__()" (the function is named underscore-underscore) or "__x()" (underscore-underscore-x) will result in this object. It will capture some environmental information, and delay the translation until it is needed.
Creating an object first and translating it later, is slower than translating it immediately. However, on the location where the message is produced, we do not yet know in what language to translate it to: that depends on the front-end, the log dispatcher.
example: use of clone()
my $s = __x "found {nr} files", nr => 5;
my $t = $s->clone(nr => 3);
my $t = $s->(nr => 3); # equivalent
print $s; # found 5 files
print $t; # found 3 files
-Option --Default
_append undef
_category undef
_class []
_classes []
_context undef
_count undef
_domain <from "use Log::Report">
_expand false
_join $" $LIST_SEPARATOR
_lang <from locale>
_msgctxt undef
_msgid undef
_plural undef
_prepend undef
_to <undef>
One message can be part of multiple classes. The STRING is used as comma- and/or blank separated list of class tokens (barewords), the ARRAY lists all tokens separately. See classes().
With this parameter, your can "borrow" translations from other textdomains. Be very careful with this (although there are good use-cases) The xgettext msgid extractor may add the used msgid to this namespace as well. To avoid that, add a harmless '+':
print __x(+"errors", _domain => 'global');
The extractor will not take the msgid when it is an expression. The '+' has no effect on the string at runtime.
Leading white-space "\s" will be added to "_prepend". Trailing white-space will be added before "_append".
White-space at the beginning and end of the string are stripped off. The white-space provided by the "_msgid" will be used.
example:
When the message was produced with
my @files = qw/one two three/;
my $msg = __xn "found one file: {file}"
, "found {nrfiles} files: {files}"
, scalar @files
, file => $files[0]
, files => \@files
, nrfiles => @files+0
, _class => 'IO, files'
, _join => ', ';
then the values can be takes from the produced message as
my $files = $msg->valueOf('files'); # returns ARRAY reference
print @$files; # 3
my $count = $msg->count; # 3
my @class = $msg->classes; # 'IO', 'files'
if($msg->inClass('files')) # true
Simplified, the above example can also be written as:
local $" = ', ';
my $msg = __xn "found one file: {files}"
, "found {_count} files: {files}"
, @files # has scalar context
, files => \@files
, _class => 'IO, files';
example: of concatenation
print __"Hello" . ' ' . __"World!";
print __("Hello")->concat(' ')->concat(__"World!")->concat("\n");
[1.20] When used in combination with a templating system, you may want to use "<content_for =" 'HTML'>> in Log::Report::Domain::configure(formatter).
example:
print $msg->toHTML('NL');
The Log::Report functions which define translation request can all have OPTIONS. Some can have VARIABLES to be interpolated in the string as well. To distinguish between the OPTIONS and VARIABLES (both a list of key-value pairs), the keys of the OPTIONS start with an underscore "_". As result of this, please avoid the use of keys which start with an underscore in variable names. On the other hand, you are allowed to interpolate OPTION values in your strings.
Interpolating
With the "__x()" or "__nx()", interpolation will take place on the translated MSGID string. The translation can contain the VARIABLE and OPTION names between curly brackets. Text between curly brackets which is not a known parameter will be left untouched.
fault __x"cannot open open {filename}", filename => $fn;
print __xn"directory {dir} contains one file"
,"directory {dir} contains {nr_files} files"
, scalar(@files) # (1) (2)
, nr_files => scalar @files # (3)
, dir => $dir;
(1) this required third parameter is used to switch between the different plural forms. English has only two forms, but some languages have many more.
(2) the "scalar" keyword is not needed, because the third parameter is in SCALAR context. You may also pass " \@files " there, because ARRAYs will be converted into their length. A HASH will be converted into the number of keys in the HASH.
(3) the "scalar" keyword is required here, because it is LIST context: otherwise all filenames will be filled-in as parameters to "__xn()". See below for the available "_count" valure, to see how the "nr_files" parameter can disappear.
Interpolation of VARIABLES
"Log::Report" uses String::Print to interpolate values in(translated) messages. This is a very powerful syntax, and you should certainly read that manual-page. Here, we only described additional features, specific to the usage of "String::Print" in "Log::Report::Message" objects.
There is no way of checking beforehand whether you have provided all required values, to be interpolated in the translated string.
For interpolating, the following rules apply:
local $" = ', ';
error __x"matching files: {files}", files => \@files;
error __x"matching files: {files}", files => \@files, _join => ', ';
Interpolation of OPTIONS
You are permitted the interpolate OPTION values in your string. This may simplify your coding. The useful names are:
. Example: using the _count
With Locale::TextDomain, you have to do
use Locale::TextDomain;
print __nx ( "One file has been deleted.\n"
, "{num} files have been deleted.\n"
, $num_files
, num => $num_files
);
With "Log::Report", you can do
use Log::Report;
print __nx ( "One file has been deleted.\n"
, "{_count} files have been deleted.\n"
, $num_files
);
Of course, you need to be aware that the name used to reference the counter is fixed to "_count". The first example works as well, but is more verbose.
Handling white-spaces
In above examples, the msgid and plural form have a trailing new-line. In general, it is much easier to write
print __x"Hello, World!\n";
than
print __x("Hello, World!") . "\n";
For the translation tables, however, that trailing new-line is "over information"; it is an layout issue, not a translation issue.
Therefore, the first form will automatically be translated into the second. All leading and trailing white-space (blanks, new-lines, tabs, ...) are removed from the msgid before the look-up, and then added to the translated string.
Leading and trailing white-space on the plural form will also be removed. However, after translation the spacing of the msgid will be used.
Avoiding repetative translations
This way of translating is somewhat expensive, because an object to handle the "__x()" is created each time.
for my $i (1..100_000)
{ print __x "Hello World {i}\n", i => $i;
}
The suggestion that Locale::TextDomain makes to improve performance, is to get the translation outside the loop, which only works without interpolation:
use Locale::TextDomain;
my $i = 42;
my $s = __x("Hello World {i}\n", i => $i);
foreach $i (1..100_000)
{ print $s;
}
Oops, not what you mean because the first value of $i is captured in the initial message object. With Log::Report, you can do it (except when you use contexts)
use Log::Report;
my $i;
my $s = __x("Hello World {i}\n", i => \$i);
foreach $i (1..100_000)
{ print $s;
}
Mind you not to write: "for my $i" in above case!!!!
You can also write an incomplete translation:
use Log::Report;
my $s = __x "Hello World {i}\n";
foreach my $i (1..100_000)
{ print $s->(i => $i);
}
In either case, the translation will be looked-up only once.
This module is part of Log-Report distribution version 1.36, built on October 27, 2023. Website: http://perl.overmeer.net/CPAN/
Copyrights 2007-2023 by [Mark Overmeer <markov@cpan.org>]. For other contributors see ChangeLog.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See http://dev.perl.org/licenses/
| 2023-10-29 | perl v5.36.0 |