xml2po 0.18.0 — © 2004, Danilo Segan

Requirements
............

 * Python
 * libxml2 and libxml2-python
 * xml2po.py (this program)
 * GNU gettext (msgfmt, msgmerge tools)

Quick install
.............

To install in the same prefix as intltool:

 $ ./configure && make && su -c "make install"


About xml2po
............

xml2po is a simple Python program which extracts translatable content
from free-form XML documents and outputs gettext compatible POT
files.

It can work it's magic with most "simple" tags, and for complicated
tags one has to provide a list of all tags which are "final" (that
will be put into one "message" in PO file), "ignored" (skipped over)
and "space preserving".

I will try to provide sane defaults for DocBook documents and other
common document types (like Mate Summaries, XHTML).  For other kinds
of documents, it is possible to use "-a" (--automatic-tags) to choose
suitable translatable pieces.  It usually works very well.

Preparing a POTemplate from XML file
........................................

 ./xml2po.py -o template.pot file.xml

By default, xml2po treats documents as DocBook.  If that's not
correct, you may choose another "document mode" by passing option "-m
MODE" on the command line.  If there's currently no special module
developed for document type you're trying to translate, use option
"-a" for automatic detection of tags, which will work well even for
simple DocBook documents.

Get back a translation from a translator
........................................

Save a translation to xx.po, where xx is language code of a
translation (i.e. "sr" for Serbian, "de" for German, ...).

Execute:
 ./xml2po.py -p xx.po -o file-xx.xml file.xml

Now you've got a nice and translated XML file in 'file-xx.xml'.

Updating a translation
......................

When base XML file changes, the real advantages of PO files come to
surface.  To merge the translation you need to first produce a new
POT file:
 ./xml2po.py -o newfile.pot newfile.xml

And then you need to use gettext "msgmerge" program to merge the
translation with the new POT file:
 msgmerge -o new-xx.po xx.po newfile.pot && mv new-xx.po xx.po

Alternatively, xml2po provides option "-u" which does exactly these
two steps for you:
 ./xml2po.py -u xx.po newfile.xml

(Note that there has been a change in suggested behaviour between
xml2po versions 1.0.9 and 1.0.10 — previously, you used only "xx",
without ".po", what emulated intltool-update behaviour; users [Ismael
Olea actually :] found that confusing, so I'm suggesting a full
filename now.)

Special handling of document types
..................................

If you want to handle some document types in a special way, you may
need to write short Python module to do it.  Currently, two special
document types come with xml2po: "docbook" and "empty".

Look at files modes/docbook.py and modes/empty.py to see how can one
write new document handling modules.  DocBook module sets "lang"
attribute on "article" element, and also adds translators to
<articleinfo> element in form of <copyright>s.

The basic features every module must provide are following functions:

- getIgnoredTags: list of tags to be skipped over, unless they're
  also "final"

- getFinalTags: list of tags that will end up as separate PO messages

- getPreserveSpaceTags: tags for which spaces should not be
  compressed 

- getStringForTranslators: string that will be added to PO file which
  translators can translate with their names

- getCommentForTranslators: comment that should document what format 
  should translators use to credit themselves

- postProcessXmlTranslation(doc, lang, credits): function which
  receives current document tree (doc), current language (lang) and
  list of translators (credits); if applicable, it should set
  language and credit translators appropriately

If a element name is in both ignored tags and final tags, then it is
treated in a somewhat special way.  It "resets" the state of parser,
but is not included as a separate translable message in PO files.

This is useful with cases like nested lists in other final tags.  In
DocBook, if we have <itemizedlist> inside <para>, we'd preferably
have it replaced in its entirety, instead of getting in message
something like:
 <itemizedlist><listitem><placeholder-1/></listitem></itemizedlist>
(where <placeholder-1/> is a another nested <para>, which is itself a
final tag).  xml2po will try to do best even in cases like this, but
giving it a hand can't hurt.

If you don't want to worry about nesting of tags, option "-a" tries to
detect what nodes are most suitable as final-tags.  This won't work
well if one can nest tags indefinitely (like with DocBook documents,
where one may have "<para>Blah... <orderedlist><listitem>...</para>"
which may become very long string, what defeats the advantages of 
PO files).

Caveats
.......

There are several situations in which xml2po produces temporary
files.  If permissions in current directory are too restrictive, they
may cause mysterious breakages, though I have tried to make it act as
sanely as possible.

Normally, xml2po doesn't substitute external entities, because such
files should be translated by themselves.  Unfortunately, Python
bindings for libxml2 are not complete, and there's no simple way to
detect if entity is external or not.  Still, there's a method
debugDumpNode which can output relevant data to a filehandle (it
doesn't work with StringIO), so I decided to create a temporary file
.xml2po-checkingentities in the current working directory.  If it is
not writeable, instead of showing an error, xml2po will replace every
entity.

Option "-p file.po" depends on program msgfmt being available and in
the path.  If that fails, you'll see an error.