Provided by: po4a_0.52-1_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.
unwrap_attributes
Attributes are wrapped by default. This option disables wrapping.
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.
escapequotes
Escape quotes in output strings. Necessary, for example, for creating string resources for use by
Android build tools.
See also: https://developer.android.com/guide/topics/resources/string-resource.html
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).
Po4a Tools 2017-08-26 Locale::Po4a::Xml(3pm)