NAME¶
Log::Report::Message - a piece of text to be translated
SYNOPSIS¶
# Created by Log::Report's __ functions
DESCRIPTION¶
Any used of a translation function, like Log::Report::__() or Log::Report::_
_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 to what language to translate: that depends on the front-end, the
log dispatcher.
METHODS¶
Constructors¶
- $obj->clone(OPTIONS, VARIABLES)
- Returns a new object which copies info from original, and
updates it with the specified OPTIONS and VARIABLES. The advantage is that
the cached translations are shared between the objects.
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
- Log::Report::Message->new(OPTIONS,
VARIABLES)
- Do not use this method directly, but use
Log::Report::__() and friends.
-Option --Default
_append undef
_category undef
_class []
_classes []
_count undef
_domain from use
_expand false
_msgid undef
_plural undef
_prepend undef
_to <undef>
- _append => STRING
- _category => INTEGER
- _class => STRING|ARRAY
- When messages are used for exception based programming, you
add "_class" parameters to the argument list. Later, with for
instance Log::Report::Dispatcher::Try::wasFatal(class), you can check the
category of the message.
One message can be part of multiple classes. The STRING is used as comma-
and/or blank separated list of class tokens, the ARRAY lists all tokens
separately. See classes().
- _classes => STRING|ARRAY
- Alternative for "_class", which cannot be used at
the same time.
- _count => INTEGER
- When defined, then "_plural" need to be defined
as well.
- _domain => STRING
- The textdomain in which this msgid is defined.
- _expand => BOOLEAN
- Indicates whether variables are filled-in.
- _msgid => MSGID
- The message label, which refers to some translation
information. Usually a string which is close the English version of the
error message. This will also be used if there is no translation
possible
- _plural => MSGID
- Can be specified when a "_count" is specified.
This plural form of the message is used to simplify translation, and as
fallback when no translations are possible: therefore, this can best
resemble an English message.
- _prepend => STRING
- _to => NAME
- Specify the NAME of a dispatcher as destination explicitly.
Short for "report {to => NAME}, ..." See to()
Accessors¶
- $obj->append
- Returns the string or Log::Report::Message object which is
appended after this one. Usually "undef".
- $obj->classes
- Returns the LIST of classes which are defined for this
message; message group indicators, as often found in exception-based
programming.
- $obj->count
- Returns the count, which is used to select the translation
alternatives.
- $obj->domain
- Returns the domain of the first translatable string in the
structure.
- $obj->msgid
- Returns the msgid which will later be translated.
- $obj->prepend
- Returns the string which is prepended to this one. Usually
"undef".
- $obj->to([NAME])
- Returns the NAME of a dispatcher if explicitly specified
with the '_to' key. Can also be used to set it. Usually, this will return
undef, because usually all dispatchers get all messages.
- $obj->valueOf(PARAMETER)
- Lookup the named PARAMETER for the message. All pre-defined
names have their own method, and should be used with preference.
example:
When the message was produced with
my @files = qw/one two three/;
my $msg = __xn "found one file: {files}"
, "found {_count} files: {files}"
, scalar @files, files => \@files
, _class => 'IO, files';
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
Processing¶
- $obj->concat(STRING|OBJECT, [PREPEND])
- This method implements the overloading of concatenation,
which is needed to delay translations even longer. When PREPEND is true,
the STRING or OBJECT (other "Log::Report::Message") needs to
prepended, otherwise it is appended.
example: of concatenation
print __"Hello" . ' ' . __"World!";
print __("Hello")->concat(' ')->concat(__"World!")->concat("\n");
- $obj->inClass(CLASS|REGEX)
- Returns true if the message is in the specified CLASS
(string) or matches the REGEX. The trueth value is the (first matching)
class.
- $obj->toString([LOCALE])
- Translate a message. If not specified, the default locale
is used.
- $obj->untranslated
- Return the concatenation of the prepend, msgid, and append
strings. Variable expansions within the msgid is not performed.
DETAILS¶
OPTIONS and VARIABLES¶
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.
Next to the name, you can specify a format code. With "gettext()", you
often see this:
printf gettext("approx pi: %.6f\n"), PI;
Locale::TextDomain has two ways.
printf __"approx pi: %.6f\n", PI;
print __x"approx pi: {approx}\n", approx => sprintf("%.6f", PI);
The first does not respect the wish to be able to reorder the arguments during
translation. The second version is quite long. With "Log::Report",
above syntaxes do work, but you can also do
print __x"approx pi: {pi%.6f}\n", pi => PI;
So: the interpolation syntax is " { name [format] } ". Other examples:
print __x "{perms} {links%2d} {user%-8s} {size%10d} {fn}\n"
, perms => '-rw-r--r--', links => 1, user => 'me'
, size => '12345', fn => $filename;
An additional advantage is the fact that not all languages produce comparable
length strings. Now, the translators can take care that the layout of tables
is optimal.
Interpolation of OPTIONS
You are permitted the interpolate OPTION values in your string. This may
simplify your coding. The useful names are:
- _msgid
- The MSGID as provided with Log::Report::__() and
Log::Report::_ _x()
- _msgid, _plural, _count
- The single MSGID and PLURAL MSGIDs, respectively the COUNT
as used with Log::Report::_ _n() and
Log::Report::__nx()
- _textdomain
- The label of the textdomain in which the translation takes
place.
- _class or _classes
- Are to be used to group reports, and can be queried with
inClass(), Log::Report::Exception::inClass(), or
Log::Report::Dispatcher::Try::wasFatal().
Interpolation of VARIABLES
There is no way of checking beforehand whether you have provided all required
values, to be interpolated in the translated string. A translation could be
specified like this:
my @files = @ARGV;
local $" = ', ';
my $s = __nx "One file specified ({files})"
, "{_count} files specified ({files})"
, scalar @files # actually, 'scalar' is not needed
, files => \@files;
For interpolating, the following rules apply:
- .
- Simple scalar values are interpolated "as
is"
- .
- References to SCALARs will collect the value on the moment
that the output is made. The "Log::Report::Message" object which
is created with the "__xn" can be seen as a closure. The
translation can be reused. See example below.
- .
- Code references can be used to create the data "under
fly". The "Log::Report::Message" object which is being
handled is passed as only argument. This is a hash in which all OPTIONS
and VARIABLES can be found.
- .
- When the value is an ARRAY, all members will be
interpolated with $" between the elements.
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;
}
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. With Log::Report, you can do
use Log::Report;
my $i;
my $s = __x("Hello World {i}", i => \$i);
foreach $i (1..100_000)
{ print $s;
}
Mind you not to write: "for my $i" in this case!!!! You can also write
an incomplete translation:
use Log::Report;
my $s = __x "Hello World {i}";
foreach my $i (1..100_000)
{ print $s->(i => $i);
}
In either case, the translation will be looked-up only once.
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.
OVERLOADING¶
- overload: as function
- When the object is used to call as function, a new object
is created with the data from the original one but updated with the new
parameters. Implemented in "clone()".
- overload: concatenation
- An (accidental) use of concatenation (a dot where a comma
should be used) would immediately stringify the object. This is avoided by
overloading that operation.
- overload: stringification
- When the object is used in string context, it will get
translated. Implemented as toString().
SEE ALSO¶
This module is part of Log-Report distribution version 0.94, built on August 23,
2011. Website:
http://perl.overmeer.net/log-report/
LICENSE¶
Copyrights 2007-2011 by Mark Overmeer. 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://www.perl.com/perl/misc/Artistic.html