GNU gettext utilities: 8. Editing PO Files

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# 8. Editing PO Files

## 8.1 KDE's PO File Editor

## 8.2 GNOME's PO File Editor

## 8.3 Emacs's PO File Editor

For those of you being the lucky users of Emacs, PO mode has been specifically created for providing a cozy environment for editing or modifying PO files. While editing a PO file, PO mode allows for the easy browsing of auxiliary and compendium PO files, as well as for following references into the set of C program sources from which PO files have been derived. It has a few special features, among which are the interactive marking of program strings as translatable, and the validation of PO files with easy repositioning to PO file lines showing errors.

For the beginning, besides main PO mode commands (see section Main PO mode Commands), you should know how to move between entries (see section Entry Positioning), and how to handle untranslated entries (see section Untranslated Entries).

### 8.3.1 Completing GNU `gettext` Installation

Once you have received, unpacked, configured and compiled the GNU `gettext` distribution, the ‘`make install`’ command puts in place the programs `xgettext`, `msgfmt`, `gettext`, and `msgmerge`, as well as their available message catalogs. To top off a comfortable installation, you might also want to make the PO mode available to your Emacs users.

During the installation of the PO mode, you might want to modify your file ‘`.emacs`’, once and for all, so it contains a few lines looking like:

    (setq auto-mode-alist
          (cons '("\\.po\\'\\|\\.po\\." . po-mode) auto-mode-alist))
    (autoload 'po-mode "po-mode" "Major mode for translators to edit PO files" t)

Later, whenever you edit some ‘`.po`’ file, or any file having the string ‘`.po.`’ within its name, Emacs loads ‘`po-mode.elc`’ (or ‘`po-mode.el`’) as needed, and automatically activates PO mode commands for the associated buffer. The string PO appears in the mode line for any buffer for which PO mode is active. Many PO files may be active at once in a single Emacs session.

If you are using Emacs version 20 or newer, and have already installed the appropriate international fonts on your system, you may also tell Emacs how to determine automatically the coding system of every PO file. This will often (but not always) cause the necessary fonts to be loaded and used for displaying the translations on your Emacs screen. For this to happen, add the lines:

    (modify-coding-system-alist 'file "\\.po\\'\\|\\.po\\."
                                'po-find-file-coding-system)
    (autoload 'po-find-file-coding-system "po-mode")

to your ‘`.emacs`’ file. If, with this, you still see boxes instead of international characters, try a different font set (via Shift Mouse button 1).

### 8.3.2 Main PO mode Commands

After setting up Emacs with something similar to the lines in Completing GNU `gettext` Installation, PO mode is activated for a window when Emacs finds a PO file in that window. This puts the window read-only and establishes a po-mode-map, which is a genuine Emacs mode, in a way that is not derived from text mode in any way. Functions found on `po-mode-hook`, if any, will be executed.

When PO mode is active in a window, the letters ‘`PO`’ appear in the mode line for that window. The mode line also displays how many entries of each kind are held in the PO file. For example, the string ‘`132t+3f+10u+2o`’ would tell the translator that the PO mode contains 132 translated entries (see section Translated Entries, 3 fuzzy entries (see section Fuzzy Entries), 10 untranslated entries (see section Untranslated Entries) and 2 obsolete entries (see section Obsolete Entries). Zero-coefficients items are not shown. So, in this example, if the fuzzy entries were unfuzzied, the untranslated entries were translated and the obsolete entries were deleted, the mode line would merely display ‘`145t`’ for the counters.

The main PO commands are those which do not fit into the other categories of subsequent sections. These allow for quitting PO mode or for managing windows in special ways.

`_`

  Undo last modification to the PO file (`po-undo`).

`Q`

  Quit processing and save the PO file (`po-quit`).

`q`

  Quit processing, possibly after confirmation (`po-confirm-and-quit`).

`0`

  Temporary leave the PO file window (`po-other-window`).

`?`
`h`

  Show help about PO mode (`po-help`).

`=`

  Give some PO file statistics (`po-statistics`).

`V`

  Batch validate the format of the whole PO file (`po-validate`).

The command `_` (`po-undo`) interfaces to the Emacs undo facility. See (emacs)Undo section `Undoing Changes' in The Emacs Editor. Each time `_` is typed, modifications which the translator did to the PO file are undone a little more. For the purpose of undoing, each PO mode command is atomic. This is especially true for the `<RET>` command: the whole edition made by using a single use of this command is undone at once, even if the edition itself implied several actions. However, while in the editing window, one can undo the edition work quite parsimoniously.

The commands `Q` (`po-quit`) and `q` (`po-confirm-and-quit`) are used when the translator is done with the PO file. The former is a bit less verbose than the latter. If the file has been modified, it is saved to disk first. In both cases, and prior to all this, the commands check if any untranslated messages remain in the PO file and, if so, the translator is asked if she really wants to leave off working with this PO file. This is the preferred way of getting rid of an Emacs PO file buffer. Merely killing it through the usual command `C-x k` (`kill-buffer`) is not the tidiest way to proceed.

The command `0` (`po-other-window`) is another, softer way, to leave PO mode, temporarily. It just moves the cursor to some other Emacs window, and pops one if necessary. For example, if the translator just got PO mode to show some source context in some other, she might discover some apparent bug in the program source that needs correction. This command allows the translator to change sex, become a programmer, and have the cursor right into the window containing the program she (or rather he) wants to modify. By later getting the cursor back in the PO file window, or by asking Emacs to edit this file once again, PO mode is then recovered.

The command `h` (`po-help`) displays a summary of all available PO mode commands. The translator should then type any character to resume normal PO mode operations. The command `?` has the same effect as `h`.

The command `=` (`po-statistics`) computes the total number of entries in the PO file, the ordinal of the current entry (counted from 1), the number of untranslated entries, the number of obsolete entries, and displays all these numbers.

The command `V` (`po-validate`) launches `msgfmt` in checking and verbose mode over the current PO file. This command first offers to save the current PO file on disk. The `msgfmt` tool, from GNU `gettext`, has the purpose of creating a MO file out of a PO file, and PO mode uses the features of this program for checking the overall format of a PO file, as well as all individual entries.

The program `msgfmt` runs asynchronously with Emacs, so the translator regains control immediately while her PO file is being studied. Error output is collected in the Emacs ‘`*compilation*`’ buffer, displayed in another window. The regular Emacs command `C-x`` (`next-error`), as well as other usual compile commands, allow the translator to reposition quickly to the offending parts of the PO file. Once the cursor is on the line in error, the translator may decide on any PO mode action which would help correcting the error.

### 8.3.3 Entry Positioning

The cursor in a PO file window is almost always part of an entry. The only exceptions are the special case when the cursor is after the last entry in the file, or when the PO file is empty. The entry where the cursor is found to be is said to be the current entry. Many PO mode commands operate on the current entry, so moving the cursor does more than allowing the translator to browse the PO file, this also selects on which entry commands operate.

Some PO mode commands alter the position of the cursor in a specialized way. A few of those special purpose positioning are described here, the others are described in following sections (for a complete list try `C-h m`):

`.`

  Redisplay the current entry (`po-current-entry`).

`n`

  Select the entry after the current one (`po-next-entry`).

`p`

  Select the entry before the current one (`po-previous-entry`).

`<`

  Select the first entry in the PO file (`po-first-entry`).

`>`

  Select the last entry in the PO file (`po-last-entry`).

`m`

  Record the location of the current entry for later use (`po-push-location`).

`r`

  Return to a previously saved entry location (`po-pop-location`).

`x`

  Exchange the current entry location with the previously saved one (`po-exchange-location`).

Any Emacs command able to reposition the cursor may be used to select the current entry in PO mode, including commands which move by characters, lines, paragraphs, screens or pages, and search commands. However, there is a kind of standard way to display the current entry in PO mode, which usual Emacs commands moving the cursor do not especially try to enforce. The command `.` (`po-current-entry`) has the sole purpose of redisplaying the current entry properly, after the current entry has been changed by means external to PO mode, or the Emacs screen otherwise altered.

It is yet to be decided if PO mode helps the translator, or otherwise irritates her, by forcing a rigid window disposition while she is doing her work. We originally had quite precise ideas about how windows should behave, but on the other hand, anyone used to Emacs is often happy to keep full control. Maybe a fixed window disposition might be offered as a PO mode option that the translator might activate or deactivate at will, so it could be offered on an experimental basis. If nobody feels a real need for using it, or a compulsion for writing it, we should drop this whole idea. The incentive for doing it should come from translators rather than programmers, as opinions from an experienced translator are surely more worth to me than opinions from programmers thinking about how others should do translation.

The commands `n` (`po-next-entry`) and `p` (`po-previous-entry`) move the cursor the entry following, or preceding, the current one. If `n` is given while the cursor is on the last entry of the PO file, or if `p` is given while the cursor is on the first entry, no move is done.

The commands `<` (`po-first-entry`) and `>` (`po-last-entry`) move the cursor to the first entry, or last entry, of the PO file. When the cursor is located past the last entry in a PO file, most PO mode commands will return an error saying ‘`After last entry`’. Moreover, the commands `<` and `>` have the special property of being able to work even when the cursor is not into some PO file entry, and one may use them for nicely correcting this situation. But even these commands will fail on a truly empty PO file. There are development plans for the PO mode for it to interactively fill an empty PO file from sources. See section Marking Translatable Strings.

The translator may decide, before working at the translation of a particular entry, that she needs to browse the remainder of the PO file, maybe for finding the terminology or phraseology used in related entries. She can of course use the standard Emacs idioms for saving the current cursor location in some register, and use that register for getting back, or else, use the location ring.

PO mode offers another approach, by which cursor locations may be saved onto a special stack. The command `m` (`po-push-location`) merely adds the location of current entry to the stack, pushing the already saved locations under the new one. The command `r` (`po-pop-location`) consumes the top stack element and repositions the cursor to the entry associated with that top element. This position is then lost, for the next `r` will move the cursor to the previously saved location, and so on until no locations remain on the stack.

If the translator wants the position to be kept on the location stack, maybe for taking a look at the entry associated with the top element, then go elsewhere with the intent of getting back later, she ought to use `m` immediately after `r`.

The command `x` (`po-exchange-location`) simultaneously repositions the cursor to the entry associated with the top element of the stack of saved locations, and replaces that top element with the location of the current entry before the move. Consequently, repeating the `x` command toggles alternatively between two entries. For achieving this, the translator will position the cursor on the first entry, use `m`, then position to the second entry, and merely use `x` for making the switch.

### 8.3.4 Normalizing Strings in Entries

There are many different ways for encoding a particular string into a PO file entry, because there are so many different ways to split and quote multi-line strings, and even, to represent special characters by backslashed escaped sequences. Some features of PO mode rely on the ability for PO mode to scan an already existing PO file for a particular string encoded into the `msgid` field of some entry. Even if PO mode has internally all the built-in machinery for implementing this recognition easily, doing it fast is technically difficult. To facilitate a solution to this efficiency problem, we decided on a canonical representation for strings.

A conventional representation of strings in a PO file is currently under discussion, and PO mode experiments with a canonical representation. Having both `xgettext` and PO mode converging towards a uniform way of representing equivalent strings would be useful, as the internal normalization needed by PO mode could be automatically satisfied when using `xgettext` from GNU `gettext`. An explicit PO mode normalization should then be only necessary for PO files imported from elsewhere, or for when the convention itself evolves.

So, for achieving normalization of at least the strings of a given PO file needing a canonical representation, the following PO mode command is available:

`M-x po-normalize`

  Tidy the whole PO file by making entries more uniform.

The special command `M-x po-normalize`, which has no associated keys, revises all entries, ensuring that strings of both original and translated entries use uniform internal quoting in the PO file. It also removes any crumb after the last entry. This command may be useful for PO files freshly imported from elsewhere, or if we ever improve on the canonical quoting format we use. This canonical format is not only meant for getting cleaner PO files, but also for greatly speeding up `msgid` string lookup for some other PO mode commands.

`M-x po-normalize` presently makes three passes over the entries. The first implements heuristics for converting PO files for GNU `gettext` 0.6 and earlier, in which `msgid` and `msgstr` fields were using K&R style C string syntax for multi-line strings. These heuristics may fail for comments not related to obsolete entries and ending with a backslash; they also depend on subsequent passes for finalizing the proper commenting of continued lines for obsolete entries. This first pass might disappear once all oldish PO files would have been adjusted. The second and third pass normalize all `msgid` and `msgstr` strings respectively. They also clean out those trailing backslashes used by XView's `msgfmt` for continued lines.

Having such an explicit normalizing command allows for importing PO files from other sources, but also eases the evolution of the current convention, evolution driven mostly by aesthetic concerns, as of now. It is easy to make suggested adjustments at a later time, as the normalizing command and eventually, other GNU `gettext` tools should greatly automate conformance. A description of the canonical string format is given below, for the particular benefit of those not having Emacs handy, and who would nevertheless want to handcraft their PO files in nice ways.

Right now, in PO mode, strings are single line or multi-line. A string goes multi-line if and only if it has embedded newlines, that is, if it matches ‘`[^\n]\n+[^\n]`’. So, we would have:

    msgstr "\n\nHello, world!\n\n\n"

but, replacing the space by a newline, this becomes:

    msgstr ""
    "\n"
    "\n"
    "Hello,\n"
    "world!\n"
    "\n"
    "\n"

We are deliberately using a caricatural example, here, to make the point clearer. Usually, multi-lines are not that bad looking. It is probable that we will implement the following suggestion. We might lump together all initial newlines into the empty string, and also all newlines introducing empty lines (that is, for n > 1, the n-1'th last newlines would go together on a separate string), so making the previous example appear:

    msgstr "\n\n"
    "Hello,\n"
    "world!\n"
    "\n\n"

There are a few yet undecided little points about string normalization, to be documented in this manual, once these questions settle.

### 8.3.5 Translated Entries

Each PO file entry for which the `msgstr` field has been filled with a translation, and which is not marked as fuzzy (see section Fuzzy Entries), is said to be a translated entry. Only translated entries will later be compiled by GNU `msgfmt` and become usable in programs. Other entry types will be excluded; translation will not occur for them.

Some commands are more specifically related to translated entry processing.

`t`

  Find the next translated entry (`po-next-translated-entry`).

`T`

  Find the previous translated entry (`po-previous-translated-entry`).

The commands `t` (`po-next-translated-entry`) and `T` (`po-previous-translated-entry`) move forwards or backwards, chasing for an translated entry. If none is found, the search is extended and wraps around in the PO file buffer.

Translated entries usually result from the translator having edited in a translation for them, Modifying Translations. However, if the variable `po-auto-fuzzy-on-edit` is not `nil`, the entry having received a new translation first becomes a fuzzy entry, which ought to be later unfuzzied before becoming an official, genuine translated entry. See section Fuzzy Entries.

### 8.3.6 Fuzzy Entries

Each PO file entry may have a set of attributes, which are qualities given a name and explicitly associated with the translation, using a special system comment. One of these attributes has the name `fuzzy`, and entries having this attribute are said to have a fuzzy translation. They are called fuzzy entries, for short.

Fuzzy entries, even if they account for translated entries for most other purposes, usually call for revision by the translator. Those may be produced by applying the program `msgmerge` to update an older translated PO files according to a new PO template file, when this tool hypothesises that some new `msgid` has been modified only slightly out of an older one, and chooses to pair what it thinks to be the old translation for the new modified entry. The slight alteration in the original string (the `msgid` string) should often be reflected in the translated string, and this requires the intervention of the translator. For this reason, `msgmerge` might mark some entries as being fuzzy.

Also, the translator may decide herself to mark an entry as fuzzy for her own convenience, when she wants to remember that the entry has to be later revisited. So, some commands are more specifically related to fuzzy entry processing.

`f`

  Find the next fuzzy entry (`po-next-fuzzy-entry`).

`F`

  Find the previous fuzzy entry (`po-previous-fuzzy-entry`).

`<TAB>`

  Remove the fuzzy attribute of the current entry (`po-unfuzzy`).

The commands `f` (`po-next-fuzzy-entry`) and `F` (`po-previous-fuzzy-entry`) move forwards or backwards, chasing for a fuzzy entry. If none is found, the search is extended and wraps around in the PO file buffer.

The command `<TAB>` (`po-unfuzzy`) removes the fuzzy attribute associated with an entry, usually leaving it translated. Further, if the variable `po-auto-select-on-unfuzzy` has not the `nil` value, the `<TAB>` command will automatically chase for another interesting entry to work on. The initial value of `po-auto-select-on-unfuzzy` is `nil`.

The initial value of `po-auto-fuzzy-on-edit` is `nil`. However, if the variable `po-auto-fuzzy-on-edit` is set to `t`, any entry edited through the `<RET>` command is marked fuzzy, as a way to ensure some kind of double check, later. In this case, the usual paradigm is that an entry becomes fuzzy (if not already) whenever the translator modifies it. If she is satisfied with the translation, she then uses `<TAB>` to pick another entry to work on, clearing the fuzzy attribute on the same blow. If she is not satisfied yet, she merely uses `<SPC>` to chase another entry, leaving the entry fuzzy.

The translator may also use the `<DEL>` command (`po-fade-out-entry`) over any translated entry to mark it as being fuzzy, when she wants to easily leave a trace she wants to later return working at this entry.

Also, when time comes to quit working on a PO file buffer with the `q` command, the translator is asked for confirmation, if fuzzy string still exists.

### 8.3.7 Untranslated Entries

When `xgettext` originally creates a PO file, unless told otherwise, it initializes the `msgid` field with the untranslated string, and leaves the `msgstr` string to be empty. Such entries, having an empty translation, are said to be untranslated entries. Later, when the programmer slightly modifies some string right in the program, this change is later reflected in the PO file by the appearance of a new untranslated entry for the modified string.

The usual commands moving from entry to entry consider untranslated entries on the same level as active entries. Untranslated entries are easily recognizable by the fact they end with ‘`msgstr ""`’.

The work of the translator might be (quite naively) seen as the process of seeking for an untranslated entry, editing a translation for it, and repeating these actions until no untranslated entries remain. Some commands are more specifically related to untranslated entry processing.

`u`

  Find the next untranslated entry (`po-next-untranslated-entry`).

`U`

  Find the previous untranslated entry (`po-previous-untransted-entry`).

`k`

  Turn the current entry into an untranslated one (`po-kill-msgstr`).

The commands `u` (`po-next-untranslated-entry`) and `U` (`po-previous-untransted-entry`) move forwards or backwards, chasing for an untranslated entry. If none is found, the search is extended and wraps around in the PO file buffer.

An entry can be turned back into an untranslated entry by merely emptying its translation, using the command `k` (`po-kill-msgstr`). See section Modifying Translations.

Also, when time comes to quit working on a PO file buffer with the `q` command, the translator is asked for confirmation, if some untranslated string still exists.

### 8.3.8 Obsolete Entries

By obsolete PO file entries, we mean those entries which are commented out, usually by `msgmerge` when it found that the translation is not needed anymore by the package being localized.

The usual commands moving from entry to entry consider obsolete entries on the same level as active entries. Obsolete entries are easily recognizable by the fact that all their lines start with `#`, even those lines containing `msgid` or `msgstr`.

Commands exist for emptying the translation or reinitializing it to the original untranslated string. Commands interfacing with the kill ring may force some previously saved text into the translation. The user may interactively edit the translation. All these commands may apply to obsolete entries, carefully leaving the entry obsolete after the fact.

Moreover, some commands are more specifically related to obsolete entry processing.

`o`

  Find the next obsolete entry (`po-next-obsolete-entry`).

`O`

  Find the previous obsolete entry (`po-previous-obsolete-entry`).

`<DEL>`

  Make an active entry obsolete, or zap out an obsolete entry (`po-fade-out-entry`).

The commands `o` (`po-next-obsolete-entry`) and `O` (`po-previous-obsolete-entry`) move forwards or backwards, chasing for an obsolete entry. If none is found, the search is extended and wraps around in the PO file buffer.

PO mode does not provide ways for un-commenting an obsolete entry and making it active, because this would reintroduce an original untranslated string which does not correspond to any marked string in the program sources. This goes with the philosophy of never introducing useless `msgid` values.

However, it is possible to comment out an active entry, so making it obsolete. GNU `gettext` utilities will later react to the disappearance of a translation by using the untranslated string. The command `<DEL>` (`po-fade-out-entry`) pushes the current entry a little further towards annihilation. If the entry is active (it is a translated entry), then it is first made fuzzy. If it is already fuzzy, then the entry is merely commented out, with confirmation. If the entry is already obsolete, then it is completely deleted from the PO file. It is easy to recycle the translation so deleted into some other PO file entry, usually one which is untranslated. See section Modifying Translations.

Here is a quite interesting problem to solve for later development of PO mode, for those nights you are not sleepy. The idea would be that PO mode might become bright enough, one of these days, to make good guesses at retrieving the most probable candidate, among all obsolete entries, for initializing the translation of a newly appeared string. I think it might be a quite hard problem to do this algorithmically, as we have to develop good and efficient measures of string similarity. Right now, PO mode completely lets the decision to the translator, when the time comes to find the adequate obsolete translation, it merely tries to provide handy tools for helping her to do so.

### 8.3.9 Modifying Translations

PO mode prevents direct modification of the PO file, by the usual means Emacs gives for altering a buffer's contents. By doing so, it pretends helping the translator to avoid little clerical errors about the overall file format, or the proper quoting of strings, as those errors would be easily made. Other kinds of errors are still possible, but some may be caught and diagnosed by the batch validation process, which the translator may always trigger by the `V` command. For all other errors, the translator has to rely on her own judgment, and also on the linguistic reports submitted to her by the users of the translated package, having the same mother tongue.

When the time comes to create a translation, correct an error diagnosed mechanically or reported by a user, the translators have to resort to using the following commands for modifying the translations.

`<RET>`

  Interactively edit the translation (`po-edit-msgstr`).

`<LFD>`
`C-j`

  Reinitialize the translation with the original, untranslated string (`po-msgid-to-msgstr`).

`k`

  Save the translation on the kill ring, and delete it (`po-kill-msgstr`).

`w`

  Save the translation on the kill ring, without deleting it (`po-kill-ring-save-msgstr`).

`y`

  Replace the translation, taking the new from the kill ring (`po-yank-msgstr`).

The command `<RET>` (`po-edit-msgstr`) opens a new Emacs window meant to edit in a new translation, or to modify an already existing translation. The new window contains a copy of the translation taken from the current PO file entry, all ready for edition, expunged of all quoting marks, fully modifiable and with the complete extent of Emacs modifying commands. When the translator is done with her modifications, she may use `C-c C-c` to close the subedit window with the automatically requoted results, or `C-c C-k` to abort her modifications. See section Details of Sub Edition, for more information.

The command `<LFD>` (`po-msgid-to-msgstr`) initializes, or reinitializes the translation with the original string. This command is normally used when the translator wants to redo a fresh translation of the original string, disregarding any previous work.

It is possible to arrange so, whenever editing an untranslated entry, the `<LFD>` command be automatically executed. If you set `po-auto-edit-with-msgid` to `t`, the translation gets initialised with the original string, in case none exists already. The default value for `po-auto-edit-with-msgid` is `nil`.

In fact, whether it is best to start a translation with an empty string, or rather with a copy of the original string, is a matter of taste or habit. Sometimes, the source language and the target language are so different that is simply best to start writing on an empty page. At other times, the source and target languages are so close that it would be a waste to retype a number of words already being written in the original string. A translator may also like having the original string right under her eyes, as she will progressively overwrite the original text with the translation, even if this requires some extra editing work to get rid of the original.

The command `k` (`po-kill-msgstr`) merely empties the translation string, so turning the entry into an untranslated one. But while doing so, its previous contents is put apart in a special place, known as the kill ring. The command `w` (`po-kill-ring-save-msgstr`) has also the effect of taking a copy of the translation onto the kill ring, but it otherwise leaves the entry alone, and does not remove the translation from the entry. Both commands use exactly the Emacs kill ring, which is shared between buffers, and which is well known already to Emacs lovers.

The translator may use `k` or `w` many times in the course of her work, as the kill ring may hold several saved translations. From the kill ring, strings may later be reinserted in various Emacs buffers. In particular, the kill ring may be used for moving translation strings between different entries of a single PO file buffer, or if the translator is handling many such buffers at once, even between PO files.

To facilitate exchanges with buffers which are not in PO mode, the translation string put on the kill ring by the `k` command is fully unquoted before being saved: external quotes are removed, multi-line strings are concatenated, and backslash escaped sequences are turned into their corresponding characters. In the special case of obsolete entries, the translation is also uncommented prior to saving.

The command `y` (`po-yank-msgstr`) completely replaces the translation of the current entry by a string taken from the kill ring. Following Emacs terminology, we then say that the replacement string is yanked into the PO file buffer. See (emacs)Yanking section `Yanking' in The Emacs Editor. The first time `y` is used, the translation receives the value of the most recent addition to the kill ring. If `y` is typed once again, immediately, without intervening keystrokes, the translation just inserted is taken away and replaced by the second most recent addition to the kill ring. By repeating `y` many times in a row, the translator may travel along the kill ring for saved strings, until she finds the string she really wanted.

When a string is yanked into a PO file entry, it is fully and automatically requoted for complying with the format PO files should have. Further, if the entry is obsolete, PO mode then appropriately push the inserted string inside comments. Once again, translators should not burden themselves with quoting considerations besides, of course, the necessity of the translated string itself respective to the program using it.

Note that `k` or `w` are not the only commands pushing strings on the kill ring, as almost any PO mode command replacing translation strings (or the translator comments) automatically saves the old string on the kill ring. The main exceptions to this general rule are the yanking commands themselves.

To better illustrate the operation of killing and yanking, let's use an actual example, taken from a common situation. When the programmer slightly modifies some string right in the program, his change is later reflected in the PO file by the appearance of a new untranslated entry for the modified string, and the fact that the entry translating the original or unmodified string becomes obsolete. In many cases, the translator might spare herself some work by retrieving the unmodified translation from the obsolete entry, then initializing the untranslated entry `msgstr` field with this retrieved translation. Once this done, the obsolete entry is not wanted anymore, and may be safely deleted.

When the translator finds an untranslated entry and suspects that a slight variant of the translation exists, she immediately uses `m` to mark the current entry location, then starts chasing obsolete entries with `o`, hoping to find some translation corresponding to the unmodified string. Once found, she uses the `<DEL>` command for deleting the obsolete entry, knowing that `<DEL>` also kills the translation, that is, pushes the translation on the kill ring. Then, `r` returns to the initial untranslated entry, and `y` then yanks the saved translation right into the `msgstr` field. The translator is then free to use `<RET>` for fine tuning the translation contents, and maybe to later use `u`, then `m` again, for going on with the next untranslated string.

When some sequence of keys has to be typed over and over again, the translator may find it useful to become better acquainted with the Emacs capability of learning these sequences and playing them back under request. See (emacs)Keyboard Macros section `Keyboard Macros' in The Emacs Editor.

### 8.3.10 Modifying Comments

Any translation work done seriously will raise many linguistic difficulties, for which decisions have to be made, and the choices further documented. These documents may be saved within the PO file in form of translator comments, which the translator is free to create, delete, or modify at will. These comments may be useful to herself when she returns to this PO file after a while.

Comments not having whitespace after the initial ‘`#`’, for example, those beginning with ‘`#.`’ or ‘`#:`’, are not translator comments, they are exclusively created by other `gettext` tools. So, the commands below will never alter such system added comments, they are not meant for the translator to modify. See section The Format of PO Files.

The following commands are somewhat similar to those modifying translations, so the general indications given for those apply here. See section Modifying Translations.

`#`

  Interactively edit the translator comments (`po-edit-comment`).

`K`

  Save the translator comments on the kill ring, and delete it (`po-kill-comment`).

`W`

  Save the translator comments on the kill ring, without deleting it (`po-kill-ring-save-comment`).

`Y`

  Replace the translator comments, taking the new from the kill ring (`po-yank-comment`).

These commands parallel PO mode commands for modifying the translation strings, and behave much the same way as they do, except that they handle this part of PO file comments meant for translator usage, rather than the translation strings. So, if the descriptions given below are slightly succinct, it is because the full details have already been given. See section Modifying Translations.

The command `#` (`po-edit-comment`) opens a new Emacs window containing a copy of the translator comments on the current PO file entry. If there are no such comments, PO mode understands that the translator wants to add a comment to the entry, and she is presented with an empty screen. Comment marks (`#`) and the space following them are automatically removed before edition, and reinstated after. For translator comments pertaining to obsolete entries, the uncommenting and recommenting operations are done twice. Once in the editing window, the keys `C-c C-c` allow the translator to tell she is finished with editing the comment. See section Details of Sub Edition, for further details.

Functions found on `po-subedit-mode-hook`, if any, are executed after the string has been inserted in the edit buffer.

The command `K` (`po-kill-comment`) gets rid of all translator comments, while saving those comments on the kill ring. The command `W` (`po-kill-ring-save-comment`) takes a copy of the translator comments on the kill ring, but leaves them undisturbed in the current entry. The command `Y` (`po-yank-comment`) completely replaces the translator comments by a string taken at the front of the kill ring. When this command is immediately repeated, the comments just inserted are withdrawn, and replaced by other strings taken along the kill ring.

On the kill ring, all strings have the same nature. There is no distinction between translation strings and translator comments strings. So, for example, let's presume the translator has just finished editing a translation, and wants to create a new translator comment to document why the previous translation was not good, just to remember what was the problem. Foreseeing that she will do that in her documentation, the translator may want to quote the previous translation in her translator comments. To do so, she may initialize the translator comments with the previous translation, still at the head of the kill ring. Because editing already pushed the previous translation on the kill ring, she merely has to type `M-w` prior to `#`, and the previous translation will be right there, all ready for being introduced by some explanatory text.

On the other hand, presume there are some translator comments already and that the translator wants to add to those comments, instead of wholly replacing them. Then, she should edit the comment right away with `#`. Once inside the editing window, she can use the regular Emacs commands `C-y` (`yank`) and `M-y` (`yank-pop`) to get the previous translation where she likes.

### 8.3.11 Details of Sub Edition

The PO subedit minor mode has a few peculiarities worth being described in fuller detail. It installs a few commands over the usual editing set of Emacs, which are described below.

`C-c C-c`

  Complete edition (`po-subedit-exit`).

`C-c C-k`

  Abort edition (`po-subedit-abort`).

`C-c C-a`

  Consult auxiliary PO files (`po-subedit-cycle-auxiliary`).

The window's contents represents a translation for a given message, or a translator comment. The translator may modify this window to her heart's content. Once this is done, the command `C-c C-c` (`po-subedit-exit`) may be used to return the edited translation into the PO file, replacing the original translation, even if it moved out of sight or if buffers were switched.

If the translator becomes unsatisfied with her translation or comment, to the extent she prefers keeping what was existent prior to the `<RET>` or `#` command, she may use the command `C-c C-k` (`po-subedit-abort`) to merely get rid of edition, while preserving the original translation or comment. Another way would be for her to exit normally with `C-c C-c`, then type `U` once for undoing the whole effect of last edition.

The command `C-c C-a` (`po-subedit-cycle-auxiliary`) allows for glancing through translations already achieved in other languages, directly while editing the current translation. This may be quite convenient when the translator is fluent at many languages, but of course, only makes sense when such completed auxiliary PO files are already available to her (see section Consulting Auxiliary PO Files).

Functions found on `po-subedit-mode-hook`, if any, are executed after the string has been inserted in the edit buffer.

While editing her translation, the translator should pay attention to not inserting unwanted `<RET>` (newline) characters at the end of the translated string if those are not meant to be there, or to removing such characters when they are required. Since these characters are not visible in the editing buffer, they are easily introduced by mistake. To help her, `<RET>` automatically puts the character `<` at the end of the string being edited, but this `<` is not really part of the string. On exiting the editing window with `C-c C-c`, PO mode automatically removes such `<` and all whitespace added after it. If the translator adds characters after the terminating `<`, it looses its delimiting property and integrally becomes part of the string. If she removes the delimiting `<`, then the edited string is taken as is, with all trailing newlines, even if invisible. Also, if the translated string ought to end itself with a genuine `<`, then the delimiting `<` may not be removed; so the string should appear, in the editing window, as ending with two `<` in a row.

When a translation (or a comment) is being edited, the translator may move the cursor back into the PO file buffer and freely move to other entries, browsing at will. If, with an edition pending, the translator wanders in the PO file buffer, she may decide to start modifying another entry. Each entry being edited has its own subedit buffer. It is possible to simultaneously edit the translation and the comment of a single entry, or to edit entries in different PO files, all at once. Typing `<RET>` on a field already being edited merely resumes that particular edit. Yet, the translator should better be comfortable at handling many Emacs windows!

Pending subedits may be completed or aborted in any order, regardless of how or when they were started. When many subedits are pending and the translator asks for quitting the PO file (with the `q` command), subedits are automatically resumed one at a time, so she may decide for each of them.

### 8.3.12 C Sources Context

PO mode is particularly powerful when used with PO files created through GNU `gettext` utilities, as those utilities insert special comments in the PO files they generate. Some of these special comments relate the PO file entry to exactly where the untranslated string appears in the program sources.

When the translator gets to an untranslated entry, she is fairly often faced with an original string which is not as informative as it normally should be, being succinct, cryptic, or otherwise ambiguous. Before choosing how to translate the string, she needs to understand better what the string really means and how tight the translation has to be. Most of the time, when problems arise, the only way left to make her judgment is looking at the true program sources from where this string originated, searching for surrounding comments the programmer might have put in there, and looking around for helping clues of any kind.

Surely, when looking at program sources, the translator will receive more help if she is a fluent programmer. However, even if she is not versed in programming and feels a little lost in C code, the translator should not be shy at taking a look, once in a while. It is most probable that she will still be able to find some of the hints she needs. She will learn quickly to not feel uncomfortable in program code, paying more attention to programmer's comments, variable and function names (if he dared choosing them well), and overall organization, than to the program code itself.

The following commands are meant to help the translator at getting program source context for a PO file entry.

`s`

  Resume the display of a program source context, or cycle through them (`po-cycle-source-reference`).

`M-s`

  Display of a program source context selected by menu (`po-select-source-reference`).

`S`

  Add a directory to the search path for source files (`po-consider-source-path`).

`M-S`

  Delete a directory from the search path for source files (`po-ignore-source-path`).

The commands `s` (`po-cycle-source-reference`) and `M-s` (`po-select-source-reference`) both open another window displaying some source program file, and already positioned in such a way that it shows an actual use of the string to be translated. By doing so, the command gives source program context for the string. But if the entry has no source context references, or if all references are unresolved along the search path for program sources, then the command diagnoses this as an error.

Even if `s` (or `M-s`) opens a new window, the cursor stays in the PO file window. If the translator really wants to get into the program source window, she ought to do it explicitly, maybe by using command `O`.

When `s` is typed for the first time, or for a PO file entry which is different of the last one used for getting source context, then the command reacts by giving the first context available for this entry, if any. If some context has already been recently displayed for the current PO file entry, and the translator wandered off to do other things, typing `s` again will merely resume, in another window, the context last displayed. In particular, if the translator moved the cursor away from the context in the source file, the command will bring the cursor back to the context. By using `s` many times in a row, with no other commands intervening, PO mode will cycle to the next available contexts for this particular entry, getting back to the first context once the last has been shown.

The command `M-s` behaves differently. Instead of cycling through references, it lets the translator choose a particular reference among many, and displays that reference. It is best used with completion, if the translator types `<TAB>` immediately after `M-s`, in response to the question, she will be offered a menu of all possible references, as a reminder of which are the acceptable answers. This command is useful only where there are really many contexts available for a single string to translate.

Program source files are usually found relative to where the PO file stands. As a special provision, when this fails, the file is also looked for, but relative to the directory immediately above it. Those two cases take proper care of most PO files. However, it might happen that a PO file has been moved, or is edited in a different place than its normal location. When this happens, the translator should tell PO mode in which directory normally sits the genuine PO file. Many such directories may be specified, and all together, they constitute what is called the search path for program sources. The command `S` (`po-consider-source-path`) is used to interactively enter a new directory at the front of the search path, and the command `M-S` (`po-ignore-source-path`) is used to select, with completion, one of the directories she does not want anymore on the search path.

### 8.3.13 Consulting Auxiliary PO Files

PO mode is able to help the knowledgeable translator, being fluent in many languages, at taking advantage of translations already achieved in other languages she just happens to know. It provides these other language translations as additional context for her own work. Moreover, it has features to ease the production of translations for many languages at once, for translators preferring to work in this way.

An auxiliary PO file is an existing PO file meant for the same package the translator is working on, but targeted to a different mother tongue language. Commands exist for declaring and handling auxiliary PO files, and also for showing contexts for the entry under work.

Here are the auxiliary file commands available in PO mode.

`a`

  Seek auxiliary files for another translation for the same entry (`po-cycle-auxiliary`).

`C-c C-a`

  Switch to a particular auxiliary file (`po-select-auxiliary`).

`A`

  Declare this PO file as an auxiliary file (`po-consider-as-auxiliary`).

`M-A`

  Remove this PO file from the list of auxiliary files (`po-ignore-as-auxiliary`).

Command `A` (`po-consider-as-auxiliary`) adds the current PO file to the list of auxiliary files, while command `M-A` (`po-ignore-as-auxiliary` just removes it.

The command `a` (`po-cycle-auxiliary`) seeks all auxiliary PO files, round-robin, searching for a translated entry in some other language having an `msgid` field identical as the one for the current entry. The found PO file, if any, takes the place of the current PO file in the display (its window gets on top). Before doing so, the current PO file is also made into an auxiliary file, if not already. So, `a` in this newly displayed PO file will seek another PO file, and so on, so repeating `a` will eventually yield back the original PO file.

The command `C-c C-a` (`po-select-auxiliary`) asks the translator for her choice of a particular auxiliary file, with completion, and then switches to that selected PO file. The command also checks if the selected file has an `msgid` field identical as the one for the current entry, and if yes, this entry becomes current. Otherwise, the cursor of the selected file is left undisturbed.

For all this to work fully, auxiliary PO files will have to be normalized, in that way that `msgid` fields should be written exactly the same way. It is possible to write `msgid` fields in various ways for representing the same string, different writing would break the proper behaviour of the auxiliary file commands of PO mode. This is not expected to be much a problem in practice, as most existing PO files have their `msgid` entries written by the same GNU `gettext` tools.

However, PO files initially created by PO mode itself, while marking strings in source files, are normalised differently. So are PO files resulting of the ‘`M-x normalize`’ command. Until these discrepancies between PO mode and other GNU `gettext` tools get fully resolved, the translator should stay aware of normalisation issues.

## 8.4 Using Translation Compendia

A compendium is a special PO file containing a set of translations recurring in many different packages. The translator can use gettext tools to build a new compendium, to add entries to her compendium, and to initialize untranslated entries, or to update already translated entries, from translations kept in the compendium.

### 8.4.1 Creating Compendia

Basically every PO file consisting of translated entries only can be declared as a valid compendium. Often the translator wants to have special compendia; let's consider two cases: concatenating PO files and extracting a message subset from a PO file.

#### 8.4.1.1 Concatenate PO Files

To concatenate several valid PO files into one compendium file you can use ‘`msgcomm`’ or ‘`msgcat`’ (the latter preferred):

    msgcat -o compendium.po file1.po file2.po

By default, `msgcat` will accumulate divergent translations for the same string. Those occurrences will be marked as `fuzzy` and highly visible decorated; calling `msgcat` on ‘`file1.po`’:

    #: src/hello.c:200
    #, c-format
    msgid "Report bugs to <%s>.\n"
    msgstr "Comunicar `bugs' a <%s>.\n"

and ‘`file2.po`’:

    #: src/bye.c:100
    #, c-format
    msgid "Report bugs to <%s>.\n"
    msgstr "Comunicar \"bugs\" a <%s>.\n"

will result in:

    #: src/hello.c:200 src/bye.c:100
    #, fuzzy, c-format
    msgid "Report bugs to <%s>.\n"
    msgstr ""
    "#-#-#-#-#  file1.po  #-#-#-#-#\n"
    "Comunicar `bugs' a <%s>.\n"
    "#-#-#-#-#  file2.po  #-#-#-#-#\n"
    "Comunicar \"bugs\" a <%s>.\n"

The translator will have to resolve this “conflict” manually; she has to decide whether the first or the second version is appropriate (or provide a new translation), to delete the “marker lines”, and finally to remove the `fuzzy` mark.

If the translator knows in advance the first found translation of a message is always the best translation she can make use to the ‘`--use-first`’ switch:

    msgcat --use-first -o compendium.po file1.po file2.po

A good compendium file must not contain `fuzzy` or untranslated entries. If input files are “dirty” you must preprocess the input files or postprocess the result using ‘`msgattrib --translated --no-fuzzy`’.

#### 8.4.1.2 Extract a Message Subset from a PO File

Nobody wants to translate the same messages again and again; thus you may wish to have a compendium file containing ‘`getopt.c`’ messages.

To extract a message subset (e.g., all ‘`getopt.c`’ messages) from an existing PO file into one compendium file you can use ‘`msggrep`’:

    msggrep --location src/getopt.c -o compendium.po file.po

### 8.4.2 Using Compendia

You can use a compendium file to initialize a translation from scratch or to update an already existing translation.

#### 8.4.2.1 Initialize a New Translation File

Since a PO file with translations does not exist the translator can merely use ‘`/dev/null`’ to fake the “old” translation file.

    msgmerge --compendium compendium.po -o file.po /dev/null file.pot

#### 8.4.2.2 Update an Existing Translation File

Concatenate the compendium file(s) and the existing PO, merge the result with the POT file and remove the obsolete entries (optional, here done using ‘`msgattrib`’):

    msgcat --use-first -o update.po compendium1.po compendium2.po file.po
    msgmerge update.po file.pot | msgattrib --no-obsolete > file.po

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