[ADD] doc: basic translations guide

doc/guides/translations.rst

@@ -0,0 +1,97 @@
+.. _guides/translations:
+
+===================
+Translating Modules
+===================
+
+Exporting translatable term
+===========================
+
+A number of terms in your modules are "implicitly translatable" as a result,
+even if you haven't done any specific work towards translation you can export
+your module's translatable terms and may find content to work with.
+
+.. todo:: needs technical features
+
+Translations export is done via the administration interface by logging into
+the backend interface and opening :menuselection:`Settings --> Translations
+--> Import / Export --> Export Translations`
+
+* leave the language to the default (new language/empty template)
+* select the `PO File`_ format
+* select your module
+* click :guilabel:`Export` and download the file
+
+.. image:: translations/po-export.*
+    :align: center
+    :width: 75%
+
+This gives you a file called :file:`{yourmodule}.po` which should be renamed
+to :file:`{yourmodule}.pot` and moved to the :file:`{yourmodule}/i18n/`
+directory. The file is a *PO Template* which simply lists translatable strings
+and from which actual translations (PO files) can be created. PO files can
+be created using msginit_, with a dedicated translation tool like POEdit_ or
+by simply copying the template to a new file called :file:`{language}.po`.
+Translation files should be put in :file:`{yourmodule}/i18n/`, next to
+:file:`{yourmodule}.pot`, and will be automatically loaded by Odoo when the
+corresponding language is installed (via :menuselection:`Settings -->
+Translations --> Load a Translation`)
+
+.. note:: translations for all loaded languages are also installed or updated
+          when installing or updating a module
+
+Implicit exports
+================
+
+Odoo automatically exports translatable strings from "data"-type content:
+
+* in non-QWeb views, all text nodes are exported as well as the content of
+  the ``string``, ``help``, ``sum``, ``confirm`` and ``placeholder``
+  attributes
+* QWeb templates (both server-side and client-side), all text nodes are
+  exported except inside ``t-translation="off"`` blocks, the content of the
+  ``title``, ``alt``, ``label`` and ``placeholder`` attributes are also
+  exported
+* for :class:`~openerp.fields.Field`, unless their model is marked with
+  ``_translate = False``:
+
+  * their ``string`` and ``help`` attributes are exported
+  * if ``selection`` is present and a list (or tuple), it's exported
+  * if their ``translate`` attribute is set to ``True``, all of their existing
+    values (across all records) are exported
+* help/error messages of :attr:`~openerp.models.Model._constraints` and
+  :attr:`~openerp.models.Model._sql_constraints` are exported
+
+Explicit exports
+================
+
+When it comes to more "imperative" situations in Python code or Javascript
+code, Odoo is not able to automatically export translatable terms and they
+must be marked explicitly for export. This is done by wrapping a literal
+string in a function call.
+
+In Python, the wrapping function is :func:`openerp.tools.translate._`::
+
+    title = _("Bank Accounts")
+
+In JavaScript, the wrapping function is generally :js:func:`openerp.web._t`:
+
+.. code-block:: javascript
+
+    title = _t("Bank Accounts")
+
+.. warning::
+
+    only literal strings can be marked for exports, not expressions and not
+    variables. For situations where strings are formatted, this means the
+    format string must be marked not the formatted string::
+
+        # bad, the extract may work but it will not correctly translate the text
+        _("Scheduled meeting with %s" % invitee.name)
+
+        # good
+        _("Scheduled meeting with %s") % invitee.name
+
+.. _PO File: http://en.wikipedia.org/wiki/Gettext#Translating
+.. _msginit: http://www.gnu.org/software/gettext/manual/gettext.html#Creating
+.. _POEdit: http://poedit.net/