# Developing Roundup

Version: | $Revision$

Note

The intended audience of this document is the developers of the core Roundup code. If you just wish to alter some behaviour of your Roundup installation, see customising roundup.

Contents

- Getting Started
- Small Changes
- CVS Access
- Project Rules
- Debugging Aids
- Internationalization Notes
  - GNU gettext package
  - Marking Strings for Translation
    - Command Line Interfaces
    - Deferred Translations
    - Web User Interface
  - Extracting Translatable Messages
  - Translating Messages
  - Compiling Message Catalogs

# Getting Started

Anyone wishing to help in the development of Roundup must read Roundup's Design Document and the implementation notes.

All development is coordinated through two resources:

- roundup-dev mailing list at http://lists.sourceforge.net/mailman/listinfo/roundup-devel
- Sourceforge's issue trackers at https://sourceforge.net/tracker/?group_id=31577

# Small Changes

Most small changes can be submitted through the Feature tracker, with patches attached that give context diffs of the affected source.

# CVS Access

To get CVS access, contact richard@users.sourceforge.net.

CVS stuff:

1. to tag a release (eg. the pre-release of 0.5.0):

       cvs tag release-0-5-0-pr1

1. to make a branch (eg. branching for code freeze/release):

       cvs co -d maint-0-5 -r release-0-5-0-pr1 roundup
       cd maint-0-5
       cvs tag -b maint-0-5

2. to check out a branch (eg. the maintenance branch for 0.5.x):

       cvs co -d maint-0-5 -r maint-0-5

3. to merge changes from the maintenance branch to the trunk, in the directory containing the HEAD checkout:

       cvs up -j maint-0-5

   though this is highly discouraged, as it generally creates a whole swag of conflicts :(

Standard tag names:

release-maj-min-patch[-sub]
  Release of the major.minor.patch release, possibly a beta or pre-release, in which case sub will be one of "b*N*" or "pr*N*".
maint-maj-min
  Maintenance branch for the major.minor release. Patch releases are tagged in this branch.

Typically, release happen like this:

1. work progresses in the HEAD branch until milestones are met,
2. a series of beta releases are tagged in the HEAD until the code is stable enough to freeze,
3. the pre-release is tagged in the HEAD, with the resultant code branched to the maintenance branch for that release,
4. bugs in the release are patched in the maintenance branch, and the final and patch releases are tagged there, and
5. further major work happens in the HEAD.

# Project Rules

Mostly the project follows Guido's Style (though naming tends to be a little relaxed sometimes). In short:

- 80 column width code
- 4-space indentations
- All modules must have a CVS Id line near the top

Other project rules:

- New functionality must be documented, even briefly (so at least we know where there's missing documentation) and changes to tracker configuration must be logged in the upgrading document.
- subscribe to roundup-checkins to receive checkin notifications from the other developers with CVS access
- discuss any changes with the other developers on roundup-dev. If nothing else, this makes sure there's no rude shocks
- write unit tests for changes you make (where possible), and ensure that all unit tests run before committing changes
- run pychecker over changed code

The administrators of the project reserve the right to boot developers who consistently check in code which is either broken or takes the codebase in directions that have not been agreed to.

# Debugging Aids

Try turning on logging of DEBUG level messages. This may be done a number of ways, depending on what it is you're testing:

1. If you're testing the database unit tests, then set the environment variable `LOGGING_LEVEL=DEBUG`. This may be done like so:

   > LOGGING_LEVEL=DEBUG python run_tests.py

   This variable replaces the older HYPERDBDEBUG environment var.

2. If you're testing a particular tracker, then set the logging level in your tracker's `config.ini`.

# Internationalization Notes

How stuff works:

1. Strings that may require translation (messages in human language) are marked in the source code. This step is discussed in Marking Strings for Translation section.
2. These strings are all extracted into Message Template File `locale/roundup.pot` (POT file). See Extracting Translatable Messages below.
3. Language teams use POT file to make Message Files for national languages (PO files). All PO files for Roundup are kept in the `locale` directory. Names of these files are target locale names, usually just 2-letter language codes. Translating Messages section of this chapter gives useful hints for message translators.
4. Translated Message Files are compiled into binary form (MO files) and stored in `locale` directory (but not kept in the Roundup CVS repository, as they may be easily made from PO files). See Compiling Message Catalogs section.
5. Roundup installer creates runtime locale structure on the file system, putting MO files in their appropriate places.
6. Runtime internationalization (I18N) services use these MO files to translate program messages into language selected by current Roundup user. Roundup command line interface uses locale name set in OS environment variable `LANGUAGE`, `LC_ALL`, `LC_MESSAGES`, or `LANG` (in that order). Roundup Web User Interface uses language selected by currently authenticated user.

Additional details may be found in GNU gettext and Python gettext module documentation.

Roundup source distribution includes POT and PO files for message translators, and also pre-built MO files to facilitate installations from source. Roundup binary distribution includes MO files only.

## GNU gettext package

This chapter is full of references to GNU gettext package. GNU gettext is a "must have" for nearly all steps of internationalizing any program, and it's manual is definetely a recommended reading for people involved in I18N.

There are GNU gettext ports to all major OS platforms. Windows binaries are available from GNU mirror sites.

Roundup does not use GNU gettext at runtime, but it's tools are used for extracting translatable messages, compiling message catalogs and, optionally, for translating messages.

Note that `gettext` package in some OS distributions means just runtime tools and libraries. In such cases gettext development tools are usually distributed in separate package named `gettext-devel`.

## Marking Strings for Translation

Strings that need translation must be marked in the source code. Following subsections explain how this is done in different cases.

If translatable string is used as a format string, it is recommended to always use named format specifiers:

    _('Index of %(classname)s') % locals()

This helps translators to better understand the context of the message and, with Python formatting, remove format specifier altogether (which is sometimes useful, especially in singular cases of Plural Forms).

When there is more than one format specifier in the translatable format string, named format specifiers must be used almost always, because translation may require different order of items.

It is better to not mark for translation strings that are not locale-dependent, as this makes it more difficult to keep track of translation completeness. For example, string `</ol></body></html>` (in `index()` method of the request handler in `roundup_server` script) has no human readable parts at all, and needs no translations. Such strings are left untranslated in PO files, and are reported as such by PO status checkers (e.g. `msgfmt --statistics`).

### Command Line Interfaces

Scripts and routines run from the command line use "static" language defined by environment variables recognized by `gettext` module from Python library (`LANGUAGE`, `LC_ALL`, `LC_MESSAGES`, and `LANG`). Primarilly, these are `roundup-admin` script and `admin.py` module, but also help texts and startup error messages in other scripts and their supporting modules.

For these interfaces, Python `gettext` engine must be initialized to use Roundup message catalogs. This is normally done by including the following line in the module imports:

    from i18n import _, ngettext

Simple translations are automatically marked by calls to builtin message translation function `_()`:

    print _("This message is translated")

Translations for messages whose grammatical depends on a number must be done by `ngettext()` function:

    print ngettext("Nuked %i file", "Nuked %i files", number_of_files_nuked)

### Deferred Translations

Sometimes translatable strings appear in the source code in untranslated form 1 and must be translated elsewhere. Example:

    for meal in ("spam", "egg", "beacon"):
        print _(meal)

In such cases, strings must be marked for translation without actual call to the translating function. To mark these strings, we use Python feature of automatic concatenation of adjacent strings and different types of string quotes:

    strings_to_translate = (
        ''"This string will be translated",
        ""'me too',
        ''r"\raw string",
        ''"""
        multiline string"""
    )

[1] | In current Roundup sources, this feature is extensively used in the `admin` module using method docstrings as help messages.

### Web User Interface

For Web User Interface, translation services are provided by Client object. Action classes have methods `_()` and `gettext()`, delegating translation to the Client instance. In HTML templates, translator object is available as context variable `i18n`.

HTML templates have special markup for translatable strings. The syntax for this markup is defined on ZPTInternationalizationSupport page. Roundup translation service currently ignores values for `i18n:domain`, `i18n:source` and `i18n:target`.

Template markup examples:

- simplest case:

      <div i18n:translate="">
       Say
       no
       more!
      </div>

  this will result in msgid `"Say no more!"`, with all leading and trailing whitespace stripped, and inner blanks replaced with single space character.

- using variable slots:

      <div i18n:translate="">
       And now...<br/>
       No.<span tal:replace="number" i18n:name="slideNo" /><br/>
       THE LARCH
      </div>

  Msgid will be: `"And now...<br /> No.${slideNo}<br /> THE LARCH"`. Template rendering will use context variable `number` (you may use any expression) to put instead of `${slideNo}` in translation.

- attribute translation:

      <button name="btn_wink" value=" Wink " i18n:attributes="value" />

  will translate the caption (and return value) for the "wink" button.

- explicit msgids. Sometimes it may be useful to specify msgid for the element translation explicitely, like this:

      <span i18n:translate="know what i mean?">this text is ignored</span>

  When rendered, element contents will be replaced by translation of the string specified in `i18n:translate` attribute.

- `i18n` in TALES. You may translate strings in TALES python expressions:

      <span tal:replace="python: i18n.gettext('Oh, wicked.')" />

- plural forms. There is no markup for plural forms in TAL i18n. You must use python expression for that:

      <span tal:replace="python: i18n.ngettext(
        'Oh but it\'s only %i shilling.',
        'Oh but it\'s only %i shillings.',
        fine) % fine"
      />

## Extracting Translatable Messages

The most common tool for message extraction is `xgettext` utility from GNU gettext package. Unfortunately, this utility has no means of Deferred Translations in Python sources. There is `xpot` tool from Francois Pinard free PO utilities that allows to mark strings for deferred translations, but it does not handle plural forms.

Roundup overcomes these limitations by using both of these utilities. This means that you need both GNU gettext tools and PO utilities to build the Message Template File yourself.

Latest Message Template File is kept in Roundup CVS and distributed with Roundup Source. If you wish to rebuild the template yourself, make sure that you have both `xpot` and `xgettext` installed and just run `gmake` (or `make`, if you are on a GNU system like linux or cygwin) in the `locale` directory.

For on-site i18n, Roundup provides command-line utility:

    roundup-gettext <tracker_home>

extracting translatable messages from tracker's html templates. This utility creates message template file `messages.pot` in `locale` subdirectory of the tracker home directory. Translated messages may be put in locale.po files (where locale is selected locale name) in the same directory, e.g.: `locale/ru.po`. These message catalogs are searched prior to system-wide translations kept in the `share` directory.

## Translating Messages

Gettext Message File (PO file) is a plain text file, that can be created by simple copying `roundup.pot` to new .po file, like this:

    $ cp roundup.pot ru.po

The name of PO file is target locale name, usually just 2-letter language code (`ru` for Russian in the above example). Alternatively, PO file may be initialized by `msginit` utility from GNU gettext tools:

    $ msginit -i roundup.pot

`msginit` will check your current locale, and initialize the header entry, setting language name, rules for plural forms and, if available, translator's name and email address. The name for PO file is also chosen based on current locale.

Next, you will need to edit this file, filling all `msgstr` lines with translations of the above `msgid` entries. PO file is a plain text file that can be edited with any text editor. However, there are several tools that may help you with this process:

> - `po-mode` for emacs. One of GNU gettext tools. Very handy, definitely recommended if you are comfortable with emacs. Cannot handle plural forms per se, but allows to edit them in simple text mode.

> - po filetype plugin for vim. Does not do as much as `po-mode`, but helps in finding untranslated and fuzzy strings, and checking code references. Please contact alexander smishlajev if you prefer this, as i have patched this plugin a bit. I have also informed the original plugin author about these changes, but got no reply so far.

> - poEdit by Vaclav Slavik. Nice cross-platform GUI editor. Unfortunately, it does not handle plural forms. Even worse, it deletes all messages with plural forms when the file is saved. Still, it may be useful to initially translate most of the messages and add plural form messages later.

> - KBabel. Being part of KDE, it works in X windows only.

>     At the first glance looks pretty hairy, with all bells and whistles. Haven't had much experience with it, though.

## Compiling Message Catalogs

Message catalogs (PO files) must be compiled into binary form (MO files) before they can be used in the application. This compilation is handled by `msgfmt` utility from GNU gettext tools. `GNUmakefile` in the `locale` directory automatically compiles all existing message catalogs after updating them from Roundup source files. If you wish to rebuild an individual MO file without making everything else, you may, for example:

    $ msgfmt --statistics -o ru.mo ru.po

This way, message translators can check their PO files without extracting strings from source. (Note: String extraction requires additional utility that is not part of GNU gettext. See Extracting Translatable Messages.)

At run time, Roundup automatically compiles message catalogs whenever PO file is changed.

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