Advanced Topics

drop will be imported. Finally, the third argument is the local directory to import. Using our previous example, a typical run of svn_load_dirs.pl might look like:

$ svn_load_dirs.pl http://svn.example.com/repos/vendor/libcomplex \ current \ /path/to/libcomplex-1.1

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You can indicate that you'd like svn_load_dirs.pl to tag the new vendor drop by passing the -t command-line option and specifying a tag name. This tag is another URL relative to the first program argument.

When you run svn_load_dirs.pl, it examines the contents of your existing “current” vendor drop, and compares them with the proposed new vendor drop. In the trivial case, there will be no files that are in one version and not the other, and the script will perform the new import without incident. If, however, there are discrepancies in the file layouts between versions, svn_load_dirs.pl will prompt you for how you would like to resolve those differences. For example, you will have the opportunity to tell the script that you know that the file math.c in version 1.0 of libcomplex was renamed to arithmetic.c in libcomplex 1.1. Any discrepancies not explained by moves are treated as regular additions and deletions.

The script also accepts a separate configuration file for setting properties on files and directories matching a regular expression that are added to the repository. This configuration file is specified to svn_load_dirs.pl using the -p command-line option. Each line of the configuration file is a whitespace-delimited set of two or four values: a Perlstyle regular expression to match the added path against, a control keyword (either break or cont), and then optionally a property name and value.

For each added path, the configured property changes whose regular expression matches the path are applied in order, unless the control specification is break (which means that no more property changes should be applied to that path). If the control specification is cont—an abbreviation for continue—then matching will continue with the next line of the configuration file.

Any whitespace in the regular expression, property name, or property value must be surrounded by either single or double quote characters. You can escape quote characters that are not used for wrapping whitespace by preceding them with a backslash (\) character. The backslash escapes only quotes when parsing the configuration file, so do not protect any other characters beyond what is necessary for the regular expression.

Localization

Localization is the act of making programs behave in a region-specific way. When a program formats numbers or dates in a way specific to your part of the world, or prints messages (or accepts input) in your native language, the program is said to be localized. This section describes steps Subversion has made towards localization.

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Advanced Topics

Understanding locales

Most modern operating systems have a notion of the “current locale”—that is, the region or country whose localization conventions are honored. These conventions—typically chosen by some runtime configuration mechanism on the computer—affect the way in which programs present data to the user, as well as the way in which they accept user input.

On Unix-like systems, you can check the values of the locale-related runtime configuration options by running the locale command:

$ locale LANG= LC_COLLATE="C" LC_CTYPE="C"

LC_MESSAGES="C" LC_MONETARY="C" LC_NUMERIC="C" LC_TIME="C"

LC_ALL="C"

The output is a list of locale-related environment variables and their current values. In this example, the variables are all set to the default C locale, but users can set these variables to specific country/language code combinations. For example, if one were to set the LC_TIME variable to fr_CA, then programs would know to present time and date information formatted according a French-speaking Canadian's expectations. And if one were to set the LC_MESSAGES variable to zh_TW, then programs would know to present human-readable messages in Traditional Chinese. Setting the LC_ALL variable has the effect of changing every locale variable to the same value. The value of LANG is used as a default value for any locale variable that is unset. To see the list of available locales on a Unix system, run the command locale -a.

On Windows, locale configuration is done via the “Regional and Language Options” control panel item. There you can view and select the values of individual settings from the available locales, and even customize (at a sickening level of detail) several of the display formatting conventions.

Subversion's use of locales

The Subversion client, svn, honors the current locale configuration in two ways. First, it notices the value of the LC_MESSAGES variable and attempts to print all messages in the specified language. For example:

$ export LC_MESSAGES=de_DE $ svn help cat

cat: Ausgabe des Inhaltes der angegebenen Dateien oder URLs Aufruf: cat ZIEL...

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This behavior works identically on both Unix and Windows systems. Note, though, that while your operating system might have support for a certain locale, the Subversion client still may not be able to speak the particular language. In order to produce localized messages, human volunteers must provide translations for each language. The translations are written using the GNU gettext package, which results in translation modules that end with the .mo filename extension. For example, the German translation file is named de.mo. These translation files are installed somewhere on your system. On Unix, they typically live in /usr/share/locale/, while on Windows they're often found in the \share\locale\ folder in Subversion's installation area. Once installed, a module is named after the program it provides translations for. For example, the de.mo file may ultimately end up installed as / usr/share/locale/de/LC_MESSAGES/subversion.mo. By browsing the installed .mo files, you can see which languages the Subversion client is able to speak.

The second way in which the locale is honored involves how svn interprets your input. The repository stores all

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