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.
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
po-ignore-source-path) is used to select, with completion,
one of the directories she does not want anymore on the search path.