Provided by: po4a_0.47-2_all 
NAME
Locale::Po4a::Xml - convert XML documents and derivates from/to PO files
DESCRIPTION
The po4a (PO for anything) project goal is to ease translations (and more interestingly,
the maintenance of translations) using gettext tools on areas where they were not expected
like documentation.
Locale::Po4a::Xml is a module to help the translation of XML documents into other [human]
languages. It can also be used as a base to build modules for XML-based documents.
TRANSLATING WITH PO4A::XML
This module can be used directly to handle generic XML documents. This will extract all
tag's content, and no attributes, since it's where the text is written in most XML based
documents.
There are some options (described in the next section) that can customize this behavior.
If this doesn't fit to your document format you're encouraged to write your own module
derived from this, to describe your format's details. See the section WRITING DERIVATE
MODULES below, for the process description.
OPTIONS ACCEPTED BY THIS MODULE
The global debug option causes this module to show the excluded strings, in order to see
if it skips something important.
These are this module's particular options:
nostrip
Prevents it to strip the spaces around the extracted strings.
wrap
Canonicalizes the string to translate, considering that whitespaces are not important,
and wraps the translated document. This option can be overridden by custom tag
options. See the "tags" option below.
caseinsensitive
It makes the tags and attributes searching to work in a case insensitive way. If it's
defined, it will treat <BooK>laNG and <BOOK>Lang as <book>lang.
includeexternal
When defined, external entities are included in the generated (translated) document,
and for the extraction of strings. If it's not defined, you will have to translate
external entities separately as independent documents.
ontagerror
This option defines the behavior of the module when it encounters invalid XML syntax
(a closing tag which does not match the last opening tag, or a tag's attribute without
value). It can take the following values:
fail
This is the default value. The module will exit with an error.
warn
The module will continue, and will issue a warning.
silent
The module will continue without any warnings.
Be careful when using this option. It is generally recommended to fix the input file.
tagsonly
Extracts only the specified tags in the "tags" option. Otherwise, it will extract all
the tags except the ones specified.
Note: This option is deprecated.
doctype
String that will try to match with the first line of the document's doctype (if
defined). If it doesn't, a warning will indicate that the document might be of a bad
type.
addlang
String indicating the path (e.g. <bbb><aaa>) of a tag where a lang="..." attribute
shall be added. The language will be defined as the basename of the PO file without
any .po extension.
tags
Space-separated list of tags you want to translate or skip. By default, the specified
tags will be excluded, but if you use the "tagsonly" option, the specified tags will
be the only ones included. The tags must be in the form <aaa>, but you can join some
(<bbb><aaa>) to say that the content of the tag <aaa> will only be translated when
it's into a <bbb> tag.
You can also specify some tag options by putting some characters in front of the tag
hierarchy. For example, you can put 'w' (wrap) or 'W' (don't wrap) to override the
default behavior specified by the global "wrap" option.
Example: W<chapter><title>
Note: This option is deprecated. You should use the translated and untranslated
options instead.
attributes
Space-separated list of tag's attributes you want to translate. You can specify the
attributes by their name (for example, "lang"), but you can prefix it with a tag
hierarchy, to specify that this attribute will only be translated when it's in the
specified tag. For example: <bbb><aaa>lang specifies that the lang attribute will only
be translated if it's in an <aaa> tag, and it's in a <bbb> tag.
foldattributes
Do not translate attributes in inline tags. Instead, replace all attributes of a tag
by po4a-id=<id>.
This is useful when attributes shall not be translated, as this simplifies the strings
for translators, and avoids typos.
customtag
Space-separated list of tags which should not be treated as tags. These tags are
treated as inline, and do not need to be closed.
break
Space-separated list of tags which should break the sequence. By default, all tags
break the sequence.
The tags must be in the form <aaa>, but you can join some (<bbb><aaa>), if a tag
(<aaa>) should only be considered when it's within another tag (<bbb>).
inline
Space-separated list of tags which should be treated as inline. By default, all tags
break the sequence.
The tags must be in the form <aaa>, but you can join some (<bbb><aaa>), if a tag
(<aaa>) should only be considered when it's within another tag (<bbb>).
placeholder
Space-separated list of tags which should be treated as placeholders. Placeholders do
not break the sequence, but the content of placeholders is translated separately.
The location of the placeholder in its block will be marked with a string similar to:
<placeholder type=\"footnote\" id=\"0\"/>
The tags must be in the form <aaa>, but you can join some (<bbb><aaa>), if a tag
(<aaa>) should only be considered when it's within another tag (<bbb>).
nodefault
Space separated list of tags that the module should not try to set by default in any
category.
cpp Support C preprocessor directives. When this option is set, po4a will consider
preprocessor directives as paragraph separators. This is important if the XML file
must be preprocessed because otherwise the directives may be inserted in the middle of
lines if po4a consider it belong to the current paragraph, and they won't be
recognized by the preprocessor. Note: the preprocessor directives must only appear
between tags (they must not break a tag).
translated
Space-separated list of tags you want to translate.
The tags must be in the form <aaa>, but you can join some (<bbb><aaa>), if a tag
(<aaa>) should only be considered when it's within another tag (<bbb>).
You can also specify some tag options by putting some characters in front of the tag
hierarchy. For example, you can put 'w' (wrap) or 'W' (don't wrap) to override the
default behavior specified by the global "wrap" option.
Example: W<chapter><title>
untranslated
Space-separated list of tags you do not want to translate.
The tags must be in the form <aaa>, but you can join some (<bbb><aaa>), if a tag
(<aaa>) should only be considered when it's within another tag (<bbb>).
defaulttranslateoption
The default categories for tags that are not in any of the translated, untranslated,
break, inline, or placeholder.
This is a set of letters:
w Tags should be translated and content can be re-wrapped.
W Tags should be translated and content should not be re-wrapped.
i Tags should be translated inline.
p Tags should be translated as placeholders.
WRITING DERIVATE MODULES
DEFINE WHAT TAGS AND ATTRIBUTES TO TRANSLATE
The simplest customization is to define which tags and attributes you want the parser to
translate. This should be done in the initialize function. First you should call the
main initialize, to get the command-line options, and then, append your custom definitions
to the options hash. If you want to treat some new options from command line, you should
define them before calling the main initialize:
$self->{options}{'new_option'}='';
$self->SUPER::initialize(%options);
$self->{options}{'_default_translated'}.=' <p> <head><title>';
$self->{options}{'attributes'}.=' <p>lang id';
$self->{options}{'_default_inline'}.=' <br>';
$self->treat_options;
You should use the _default_inline, _default_break, _default_placeholder,
_default_translated, _default_untranslated, and _default_attributes options in derivated
modules. This allow users to override the default behavior defined in your module with
command line options.
OVERRIDING THE found_string FUNCTION
Another simple step is to override the function "found_string", which receives the
extracted strings from the parser, in order to translate them. There you can control
which strings you want to translate, and perform transformations to them before or after
the translation itself.
It receives the extracted text, the reference on where it was, and a hash that contains
extra information to control what strings to translate, how to translate them and to
generate the comment.
The content of these options depends on the kind of string it is (specified in an entry of
this hash):
type="tag"
The found string is the content of a translatable tag. The entry "tag_options"
contains the option characters in front of the tag hierarchy in the module "tags"
option.
type="attribute"
Means that the found string is the value of a translatable attribute. The entry
"attribute" has the name of the attribute.
It must return the text that will replace the original in the translated document. Here's
a basic example of this function:
sub found_string {
my ($self,$text,$ref,$options)=@_;
$text = $self->translate($text,$ref,"type ".$options->{'type'},
'wrap'=>$self->{options}{'wrap'});
return $text;
}
There's another simple example in the new Dia module, which only filters some strings.
MODIFYING TAG TYPES (TODO)
This is a more complex one, but it enables a (almost) total customization. It's based on
a list of hashes, each one defining a tag type's behavior. The list should be sorted so
that the most general tags are after the most concrete ones (sorted first by the beginning
and then by the end keys). To define a tag type you'll have to make a hash with the
following keys:
beginning
Specifies the beginning of the tag, after the "<".
end Specifies the end of the tag, before the ">".
breaking
It says if this is a breaking tag class. A non-breaking (inline) tag is one that can
be taken as part of the content of another tag. It can take the values false (0),
true (1) or undefined. If you leave this undefined, you'll have to define the
f_breaking function that will say whether a concrete tag of this class is a breaking
tag or not.
f_breaking
It's a function that will tell if the next tag is a breaking one or not. It should be
defined if the breaking option is not.
f_extract
If you leave this key undefined, the generic extraction function will have to extract
the tag itself. It's useful for tags that can have other tags or special structures
in them, so that the main parser doesn't get mad. This function receives a boolean
that says if the tag should be removed from the input stream or not.
f_translate
This function receives the tag (in the get_string_until() format) and returns the
translated tag (translated attributes or all needed transformations) as a single
string.
INTERNAL FUNCTIONS used to write derivated parsers
WORKING WITH TAGS
get_path()
This function returns the path to the current tag from the document's root, in the
form <html><body><p>.
An additional array of tags (without brackets) can be passed as argument. These path
elements are added to the end of the current path.
tag_type()
This function returns the index from the tag_types list that fits to the next tag in
the input stream, or -1 if it's at the end of the input file.
extract_tag($$)
This function returns the next tag from the input stream without the beginning and
end, in an array form, to maintain the references from the input file. It has two
parameters: the type of the tag (as returned by tag_type) and a boolean, that
indicates if it should be removed from the input stream.
get_tag_name(@)
This function returns the name of the tag passed as an argument, in the array form
returned by extract_tag.
breaking_tag()
This function returns a boolean that says if the next tag in the input stream is a
breaking tag or not (inline tag). It leaves the input stream intact.
treat_tag()
This function translates the next tag from the input stream. Using each tag type's
custom translation functions.
tag_in_list($@)
This function returns a string value that says if the first argument (a tag hierarchy)
matches any of the tags from the second argument (a list of tags or tag hierarchies).
If it doesn't match, it returns 0. Else, it returns the matched tag's options (the
characters in front of the tag) or 1 (if that tag doesn't have options).
WORKING WITH ATTRIBUTES
treat_attributes(@)
This function handles the translation of the tags' attributes. It receives the tag
without the beginning / end marks, and then it finds the attributes, and it translates
the translatable ones (specified by the module option "attributes"). This returns a
plain string with the translated tag.
WORKING WITH THE MODULE OPTIONS
treat_options()
This function fills the internal structures that contain the tags, attributes and
inline data with the options of the module (specified in the command-line or in the
initialize function).
GETTING TEXT FROM THE INPUT DOCUMENT
get_string_until($%)
This function returns an array with the lines (and references) from the input document
until it finds the first argument. The second argument is an options hash. Value 0
means disabled (the default) and 1, enabled.
The valid options are:
include
This makes the returned array to contain the searched text
remove
This removes the returned stream from the input
unquoted
This ensures that the searched text is outside any quotes
skip_spaces(\@)
This function receives as argument the reference to a paragraph (in the format
returned by get_string_until), skips his heading spaces and returns them as a simple
string.
join_lines(@)
This function returns a simple string with the text from the argument array
(discarding the references).
STATUS OF THIS MODULE
This module can translate tags and attributes.
TODO LIST
DOCTYPE (ENTITIES)
There is a minimal support for the translation of entities. They are translated as a
whole, and tags are not taken into account. Multilines entities are not supported and
entities are always rewrapped during the translation.
MODIFY TAG TYPES FROM INHERITED MODULES (move the tag_types structure inside the $self
hash?)
SEE ALSO
Locale::Po4a::TransTractor(3pm), po4a(7)
AUTHORS
Jordi Vilalta <jvprat@gmail.com>
Nicolas François <nicolas.francois@centraliens.net>
COPYRIGHT AND LICENSE
Copyright (c) 2004 by Jordi Vilalta <jvprat@gmail.com>
Copyright (c) 2008-2009 by Nicolas François <nicolas.francois@centraliens.net>
This program is free software; you may redistribute it and/or modify it under the terms of
GPL (see the COPYING file).