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  17 <H1><A NAME="SEC7" HREF="gettext_toc.html#TOC7">PO Files and PO Mode Basics</A></H1>
  18
  19 <P>
  20 The GNU <CODE>gettext</CODE> toolset helps programmers and translators
  21 at producing, updating and using translation files, mainly those
  22 PO files which are textual, editable files.  This chapter stresses
  23 the format of PO files, and contains a PO mode starter.  PO mode
  24 description is spread throughout this manual instead of being concentrated
  25 in one place.  Here we present only the basics of PO mode.
  26
  27 </P>
  28
  29
  30
  31 <H2><A NAME="SEC8" HREF="gettext_toc.html#TOC8">Completing GNU <CODE>gettext</CODE> Installation</A></H2>
  32
  33 <P>
  34 Once you have received, unpacked, configured and compiled the GNU
  35 <CODE>gettext</CODE> distribution, the <SAMP>`make install'</SAMP> command puts in
  36 place the programs <CODE>xgettext</CODE>, <CODE>msgfmt</CODE>, <CODE>gettext</CODE>, and
  37 <CODE>msgmerge</CODE>, as well as their available message catalogs.  To
  38 top off a comfortable installation, you might also want to make the
  39 PO mode available to your GNU Emacs users.
  40
  41 </P>
  42 <P>
  43 During the installation of the PO mode, you might want modify your
  44 file <TT>`.emacs'</TT>, once and for all, so it contains a few lines looking
  45 like:
  46
  47 </P>
  48
  49 <PRE>
  50 (setq auto-mode-alist
  51       (cons '("\\.po[tx]?\\'\\|\\.po\\." . po-mode) auto-mode-alist))
  52 (autoload 'po-mode "po-mode")
  53 </PRE>
  54
  55 <P>
  56 Later, whenever you edit some <TT>`.po'</TT>, <TT>`.pot'</TT> or <TT>`.pox'</TT>
  57 file, or any file having the string <SAMP>`.po.'</SAMP> within its name,
  58 Emacs loads <TT>`po-mode.elc'</TT> (or <TT>`po-mode.el'</TT>) as needed, and
  59 automatically activates PO mode commands for the associated buffer.
  60 The string <EM>PO</EM> appears in the mode line for any buffer for
  61 which PO mode is active.  Many PO files may be active at once in a
  62 single Emacs session.
  63
  64 </P>
  65 <P>
  66 If you are using Emacs version 20 or better, and have already installed
  67 the appropriate international fonts on your system, you may also manage
  68 for the these fonts to be automatically loaded and used for displaying
  69 the translations on your Emacs screen, whenever necessary.  For this to
  70 happen, you might want to add the lines:
  71
  72 </P>
  73
  74 <PRE>
  75 (autoload 'po-find-file-coding-system "po-mode")
  76 (modify-coding-system-alist 'file "\\.po[tx]?\\'\\|\\.po\\."
  77                             'po-find-file-coding-system)
  78 </PRE>
  79
  80 <P>
  81 to your <TT>`.emacs'</TT> file.
  82
  83 </P>
  84
  85
  86 <H2><A NAME="SEC9" HREF="gettext_toc.html#TOC9">The Format of PO Files</A></H2>
  87
  88 <P>
  89 A PO file is made up of many entries, each entry holding the relation
  90 between an original untranslated string and its corresponding
  91 translation.  All entries in a given PO file usually pertain
  92 to a single project, and all translations are expressed in a single
  93 target language.  One PO file <STRONG>entry</STRONG> has the following schematic
  94 structure:
  95
  96 </P>
  97
  98 <PRE>
  99 <VAR>white-space</VAR>
 100 #  <VAR>translator-comments</VAR>
 101 #. <VAR>automatic-comments</VAR>
 102 #: <VAR>reference</VAR>...
 103 #, <VAR>flag</VAR>...
 104 msgid <VAR>untranslated-string</VAR>
 105 msgstr <VAR>translated-string</VAR>
 106 </PRE>
 107
 108 <P>
 109 The general structure of a PO file should be well understood by
 110 the translator.  When using PO mode, very little has to be known
 111 about the format details, as PO mode takes care of them for her.
 112
 113 </P>
 114 <P>
 115 Entries begin with some optional white space.  Usually, when generated
 116 through GNU <CODE>gettext</CODE> tools, there is exactly one blank line
 117 between entries.  Then comments follow, on lines all starting with the
 118 character <KBD>#</KBD>.  There are two kinds of comments: those which have
 119 some white space immediately following the <KBD>#</KBD>, which comments are
 120 created and maintained exclusively by the translator, and those which
 121 have some non-white character just after the <KBD>#</KBD>, which comments
 122 are created and maintained automatically by GNU <CODE>gettext</CODE> tools.
 123 All comments, of either kind, are optional.
 124
 125 </P>
 126 <P>
 127 After white space and comments, entries show two strings, giving
 128 first the untranslated string as it appears in the original program
 129 sources, and then, the translation of this string.  The original
 130 string is introduced by the keyword <CODE>msgid</CODE>, and the translation,
 131 by <CODE>msgstr</CODE>.  The two strings, untranslated and translated,
 132 are quoted in various ways in the PO file, using <KBD>"</KBD>
 133 delimiters and <KBD>\</KBD> escapes, but the translator does not really
 134 have to pay attention to the precise quoting format, as PO mode fully
 135 intend to take care of quoting for her.
 136
 137 </P>
 138 <P>
 139 The <CODE>msgid</CODE> strings, as well as automatic comments, are produced
 140 and managed by other GNU <CODE>gettext</CODE> tools, and PO mode does not
 141 provide means for the translator to alter these.  The most she can
 142 do is merely deleting them, and only by deleting the whole entry.
 143 On the other hand, the <CODE>msgstr</CODE> string, as well as translator
 144 comments, are really meant for the translator, and PO mode gives her
 145 the full control she needs.
 146
 147 </P>
 148 <P>
 149 The comment lines beginning with <KBD>#,</KBD> are special because they are
 150 not completely ignored by the programs as comments generally are.  The
 151 comma separated list of <VAR>flag</VAR>s is used by the <CODE>msgfmt</CODE>
 152 program to give the user some better disgnostic messages.  Currently
 153 there are two forms of flags defined:
 154
 155 </P>
 156 <DL COMPACT>
 157
 158 <DT><KBD>fuzzy</KBD>
 159 <DD>
 160 This flag can be generated by the <CODE>msgmerge</CODE> program or it can be
 161 inserted by the translator herself.  It shows that the <CODE>msgstr</CODE>
 162 string might not be a correct translation (anymore).  Only the translator
 163 can judge if the translation requires further modification, or is
 164 acceptable as is.  Once satisfied with the translation, she then removes
 165 this <KBD>fuzzy</KBD> attribute.  The <CODE>msgmerge</CODE> programs inserts this
 166 when it combined the <CODE>msgid</CODE> and <CODE>msgstr</CODE> entries after fuzzy
 167 search only.  See section <A HREF="gettext_5.html#SEC26">Fuzzy Entries</A>.
 168
 169 <DT><KBD>c-format</KBD>
 170 <DD>
 171 <DT><KBD>no-c-format</KBD>
 172 <DD>
 173 These flags should not be added by a human.  Instead only the
 174 <CODE>xgettext</CODE> program adds them.  In an automatized PO file processing
 175 system as proposed here the user changes would be thrown away again as
 176 soon as the <CODE>xgettext</CODE> program generates a new template file.
 177
 178 In case the <KBD>c-format</KBD> flag is given for a string the <CODE>msgfmt</CODE>
 179 does some more tests to check to validity of the translation.
 180 See section <A HREF="gettext_6.html#SEC33">Invoking the <CODE>msgfmt</CODE> Program</A>.
 181
 182 </DL>
 183
 184 <P>
 185 It happens that some lines, usually whitespace or comments, follow the
 186 very last entry of a PO file.  Such lines are not part of any entry,
 187 and PO mode is unable to take action on those lines.  By using the
 188 PO mode function <KBD>M-x po-normalize</KBD>, the translator may get
 189 rid of those spurious lines.  See section <A HREF="gettext_2.html#SEC12">Normalizing Strings in Entries</A>.
 190
 191 </P>
 192 <P>
 193 The remainder of this section may be safely skipped by those using
 194 PO mode, yet it may be interesting for everybody to have a better
 195 idea of the precise format of a PO file.  On the other hand, those
 196 not having GNU Emacs handy should carefully continue reading on.
 197
 198 </P>
 199 <P>
 200 Each of <VAR>untranslated-string</VAR> and <VAR>translated-string</VAR> respects
 201 the C syntax for a character string, including the surrounding quotes
 202 and imbedded backslashed escape sequences.  When the time comes
 203 to write multi-line strings, one should not use escaped newlines.
 204 Instead, a closing quote should follow the last character on the
 205 line to be continued, and an opening quote should resume the string
 206 at the beginning of the following PO file line.  For example:
 207
 208 </P>
 209
 210 <PRE>
 211 msgid ""
 212 "Here is an example of how one might continue a very long string\n"
 213 "for the common case the string represents multi-line output.\n"
 214 </PRE>
 215
 216 <P>
 217 In this example, the empty string is used on the first line, to
 218 allow better alignment of the <KBD>H</KBD> from the word <SAMP>`Here'</SAMP>
 219 over the <KBD>f</KBD> from the word <SAMP>`for'</SAMP>.  In this example, the
 220 <CODE>msgid</CODE> keyword is followed by three strings, which are meant
 221 to be concatenated.  Concatenating the empty string does not change
 222 the resulting overall string, but it is a way for us to comply with
 223 the necessity of <CODE>msgid</CODE> to be followed by a string on the same
 224 line, while keeping the multi-line presentation left-justified, as
 225 we find this to be a cleaner disposition.  The empty string could have
 226 been omitted, but only if the string starting with <SAMP>`Here'</SAMP> was
 227 promoted on the first line, right after <CODE>msgid</CODE>.<A NAME="DOCF1" HREF="gettext_foot.html#FOOT1">(1)</A> It was not really necessary
 228 either to switch between the two last quoted strings immediately after
 229 the newline <SAMP>`\n'</SAMP>, the switch could have occurred after <EM>any</EM>
 230 other character, we just did it this way because it is neater.
 231
 232 </P>
 233 <P>
 234 One should carefully distinguish between end of lines marked as
 235 <SAMP>`\n'</SAMP> <EM>inside</EM> quotes, which are part of the represented
 236 string, and end of lines in the PO file itself, outside string quotes,
 237 which have no incidence on the represented string.
 238
 239 </P>
 240 <P>
 241 Outside strings, white lines and comments may be used freely.
 242 Comments start at the beginning of a line with <SAMP>`#'</SAMP> and extend
 243 until the end of the PO file line.  Comments written by translators
 244 should have the initial <SAMP>`#'</SAMP> immediately followed by some white
 245 space.  If the <SAMP>`#'</SAMP> is not immediately followed by white space,
 246 this comment is most likely generated and managed by specialized GNU
 247 tools, and might disappear or be replaced unexpectedly when the PO
 248 file is given to <CODE>msgmerge</CODE>.
 249
 250 </P>
 251
 252
 253 <H2><A NAME="SEC10" HREF="gettext_toc.html#TOC10">Main PO mode Commands</A></H2>
 254
 255 <P>
 256 After setting up Emacs with something similar to the lines in
 257 section <A HREF="gettext_2.html#SEC8">Completing GNU <CODE>gettext</CODE> Installation</A>, PO mode is activated for a window when Emacs finds a
 258 PO file in that window.  This puts the window read-only and establishes a
 259 po-mode-map, which is a genuine Emacs mode, in a way that is not derived
 260 from text mode in any way.  Functions found on <CODE>po-mode-hook</CODE>,
 261 if any, will be executed.
 262
 263 </P>
 264 <P>
 265 When PO mode is active in a window, the letters <SAMP>`PO'</SAMP> appear
 266 in the mode line for that window.  The mode line also displays how
 267 many entries of each kind are held in the PO file.  For example,
 268 the string <SAMP>`132t+3f+10u+2o'</SAMP> would tell the translator that the
 269 PO mode contains 132 translated entries (see section <A HREF="gettext_5.html#SEC25">Translated Entries</A>,
 270 3 fuzzy entries (see section <A HREF="gettext_5.html#SEC26">Fuzzy Entries</A>), 10 untranslated entries
 271 (see section <A HREF="gettext_5.html#SEC27">Untranslated Entries</A>) and 2 obsolete entries (see section <A HREF="gettext_5.html#SEC28">Obsolete Entries</A>).  Zero-coefficients items are not shown.  So, in this example, if
 272 the fuzzy entries were unfuzzied, the untranslated entries were translated
 273 and the obsolete entries were deleted, the mode line would merely display
 274 <SAMP>`145t'</SAMP> for the counters.
 275
 276 </P>
 277 <P>
 278 The main PO commands are those which do not fit into the other categories of
 279 subsequent sections.  These allow for quitting PO mode or for managing windows
 280 in special ways.
 281
 282 </P>
 283 <DL COMPACT>
 284
 285 <DT><KBD>U</KBD>
 286 <DD>
 287 Undo last modification to the PO file.
 288
 289 <DT><KBD>Q</KBD>
 290 <DD>
 291 Quit processing and save the PO file.
 292
 293 <DT><KBD>q</KBD>
 294 <DD>
 295 Quit processing, possibly after confirmation.
 296
 297 <DT><KBD>O</KBD>
 298 <DD>
 299 Temporary leave the PO file window.
 300
 301 <DT><KBD>?</KBD>
 302 <DD>
 303 <DT><KBD>h</KBD>
 304 <DD>
 305 Show help about PO mode.
 306
 307 <DT><KBD>=</KBD>
 308 <DD>
 309 Give some PO file statistics.
 310
 311 <DT><KBD>V</KBD>
 312 <DD>
 313 Batch validate the format of the whole PO file.
 314
 315 </DL>
 316
 317 <P>
 318 The command <KBD>U</KBD> (<CODE>po-undo</CODE>) interfaces to the GNU Emacs
 319 <EM>undo</EM> facility.  See section `Undoing Changes' in <CITE>The Emacs Editor</CITE>.  Each time <KBD>U</KBD> is typed, modifications which the translator
 320 did to the PO file are undone a little more.  For the purpose of
 321 undoing, each PO mode command is atomic.  This is especially true for
 322 the <KBD><KBD>RET</KBD></KBD> command: the whole edition made by using a single
 323 use of this command is undone at once, even if the edition itself
 324 implied several actions.  However, while in the editing window, one
 325 can undo the edition work quite parsimoniously.
 326
 327 </P>
 328 <P>
 329 The commands <KBD>Q</KBD> (<CODE>po-quit</CODE>) and <KBD>q</KBD>
 330 (<CODE>po-confirm-and-quit</CODE>) are used when the translator is done with the
 331 PO file.  The former is a bit less verbose than the latter.  If the file
 332 has been modified, it is saved to disk first.  In both cases, and prior to
 333 all this, the commands check if some untranslated message remains in the
 334 PO file and, if yes, the translator is asked if she really wants to leave
 335 off working with this PO file.  This is the preferred way of getting rid
 336 of an Emacs PO file buffer.  Merely killing it through the usual command
 337 <KBD>C-x k</KBD> (<CODE>kill-buffer</CODE>) is not the tidiest way to proceed.
 338
 339 </P>
 340 <P>
 341 The command <KBD>O</KBD> (<CODE>po-other-window</CODE>) is another, softer way,
 342 to leave PO mode, temporarily.  It just moves the cursor to some other
 343 Emacs window, and pops one if necessary.  For example, if the translator
 344 just got PO mode to show some source context in some other, she might
 345 discover some apparent bug in the program source that needs correction.
 346 This command allows the translator to change sex, become a programmer,
 347 and have the cursor right into the window containing the program she
 348 (or rather <EM>he</EM>) wants to modify.  By later getting the cursor back
 349 in the PO file window, or by asking Emacs to edit this file once again,
 350 PO mode is then recovered.
 351
 352 </P>
 353 <P>
 354 The command <KBD>h</KBD> (<CODE>po-help</CODE>) displays a summary of all available PO
 355 mode commands.  The translator should then type any character to resume
 356 normal PO mode operations.  The command <KBD>?</KBD> has the same effect
 357 as <KBD>h</KBD>.
 358
 359 </P>
 360 <P>
 361 The command <KBD>=</KBD> (<CODE>po-statistics</CODE>) computes the total number of
 362 entries in the PO file, the ordinal of the current entry (counted from
 363 1), the number of untranslated entries, the number of obsolete entries,
 364 and displays all these numbers.
 365
 366 </P>
 367 <P>
 368 The command <KBD>V</KBD> (<CODE>po-validate</CODE>) launches <CODE>msgfmt</CODE> in verbose
 369 mode over the current PO file.  This command first offers to save the
 370 current PO file on disk.  The <CODE>msgfmt</CODE> tool, from GNU <CODE>gettext</CODE>,
 371 has the purpose of creating a MO file out of a PO file, and PO mode uses
 372 the features of this program for checking the overall format of a PO file,
 373 as well as all individual entries.
 374
 375 </P>
 376 <P>
 377 The program <CODE>msgfmt</CODE> runs asynchronously with Emacs, so the
 378 translator regains control immediately while her PO file is being studied.
 379 Error output is collected in the GNU Emacs <SAMP>`*compilation*'</SAMP> buffer,
 380 displayed in another window.  The regular GNU Emacs command <KBD>C-x`</KBD>
 381 (<CODE>next-error</CODE>), as well as other usual compile commands, allow the
 382 translator to reposition quickly to the offending parts of the PO file.
 383 Once the cursor is on the line in error, the translator may decide on
 384 any PO mode action which would help correcting the error.
 385
 386 </P>
 387
 388
 389 <H2><A NAME="SEC11" HREF="gettext_toc.html#TOC11">Entry Positioning</A></H2>
 390
 391 <P>
 392 The cursor in a PO file window is almost always part of
 393 an entry.  The only exceptions are the special case when the cursor
 394 is after the last entry in the file, or when the PO file is
 395 empty.  The entry where the cursor is found to be is said to be the
 396 current entry.  Many PO mode commands operate on the current entry,
 397 so moving the cursor does more than allowing the translator to browse
 398 the PO file, this also selects on which entry commands operate.
 399
 400 </P>
 401 <P>
 402 Some PO mode commands alter the position of the cursor in a specialized
 403 way.  A few of those special purpose positioning are described here,
 404 the others are described in following sections.
 405
 406 </P>
 407 <DL COMPACT>
 408
 409 <DT><KBD>.</KBD>
 410 <DD>
 411 Redisplay the current entry.
 412
 413 <DT><KBD>n</KBD>
 414 <DD>
 415 <DT><KBD>n</KBD>
 416 <DD>
 417 Select the entry after the current one.
 418
 419 <DT><KBD>p</KBD>
 420 <DD>
 421 <DT><KBD>p</KBD>
 422 <DD>
 423 Select the entry before the current one.
 424
 425 <DT><KBD>&#60;</KBD>
 426 <DD>
 427 Select the first entry in the PO file.
 428
 429 <DT><KBD>&#62;</KBD>
 430 <DD>
 431 Select the last entry in the PO file.
 432
 433 <DT><KBD>m</KBD>
 434 <DD>
 435 Record the location of the current entry for later use.
 436
 437 <DT><KBD>l</KBD>
 438 <DD>
 439 Return to a previously saved entry location.
 440
 441 <DT><KBD>x</KBD>
 442 <DD>
 443 Exchange the current entry location with the previously saved one.
 444
 445 </DL>
 446
 447 <P>
 448 Any GNU Emacs command able to reposition the cursor may be used
 449 to select the current entry in PO mode, including commands which
 450 move by characters, lines, paragraphs, screens or pages, and search
 451 commands.  However, there is a kind of standard way to display the
 452 current entry in PO mode, which usual GNU Emacs commands moving
 453 the cursor do not especially try to enforce.  The command <KBD>.</KBD>
 454 (<CODE>po-current-entry</CODE>) has the sole purpose of redisplaying the
 455 current entry properly, after the current entry has been changed by
 456 means external to PO mode, or the Emacs screen otherwise altered.
 457
 458 </P>
 459 <P>
 460 It is yet to be decided if PO mode helps the translator, or otherwise
 461 irritates her, by forcing a rigid window disposition while she
 462 is doing her work.  We originally had quite precise ideas about
 463 how windows should behave, but on the other hand, anyone used to
 464 GNU Emacs is often happy to keep full control.  Maybe a fixed window
 465 disposition might be offered as a PO mode option that the translator
 466 might activate or deactivate at will, so it could be offered on an
 467 experimental basis.  If nobody feels a real need for using it, or
 468 a compulsion for writing it, we should drop this whole idea.
 469 The incentive for doing it should come from translators rather than
 470 programmers, as opinions from an experienced translator are surely
 471 more worth to me than opinions from programmers <EM>thinking</EM> about
 472 how <EM>others</EM> should do translation.
 473
 474 </P>
 475 <P>
 476 The commands <KBD>n</KBD> (<CODE>po-next-entry</CODE>) and <KBD>p</KBD>
 477 (<CODE>po-previous-entry</CODE>) move the cursor the entry following,
 478 or preceding, the current one.  If <KBD>n</KBD> is given while the
 479 cursor is on the last entry of the PO file, or if <KBD>p</KBD>
 480 is given while the cursor is on the first entry, no move is done.
 481
 482 </P>
 483 <P>
 484 The commands <KBD>&#60;</KBD> (<CODE>po-first-entry</CODE>) and <KBD>&#62;</KBD>
 485 (<CODE>po-last-entry</CODE>) move the cursor to the first entry, or last
 486 entry, of the PO file.  When the cursor is located past the last
 487 entry in a PO file, most PO mode commands will return an error saying
 488 <SAMP>`After last entry'</SAMP>.  Moreover, the commands <KBD>&#60;</KBD> and <KBD>&#62;</KBD>
 489 have the special property of being able to work even when the cursor
 490 is not into some PO file entry, and one may use them for nicely
 491 correcting this situation.  But even these commands will fail on a
 492 truly empty PO file.  There are development plans for the PO mode for it
 493 to interactively fill an empty PO file from sources.  See section <A HREF="gettext_3.html#SEC16">Marking Translatable Strings</A>.
 494
 495 </P>
 496 <P>
 497 The translator may decide, before working at the translation of
 498 a particular entry, that she needs to browse the remainder of the
 499 PO file, maybe for finding the terminology or phraseology used
 500 in related entries.  She can of course use the standard Emacs idioms
 501 for saving the current cursor location in some register, and use that
 502 register for getting back, or else, use the location ring.
 503
 504 </P>
 505 <P>
 506 PO mode offers another approach, by which cursor locations may be saved
 507 onto a special stack.  The command <KBD>m</KBD> (<CODE>po-push-location</CODE>)
 508 merely adds the location of current entry to the stack, pushing
 509 the already saved locations under the new one.  The command
 510 <KBD>r</KBD> (<CODE>po-pop-location</CODE>) consumes the top stack element and
 511 reposition the cursor to the entry associated with that top element.
 512 This position is then lost, for the next <KBD>r</KBD> will move the cursor
 513 to the previously saved location, and so on until no locations remain
 514 on the stack.
 515
 516 </P>
 517 <P>
 518 If the translator wants the position to be kept on the location stack,
 519 maybe for taking a look at the entry associated with the top
 520 element, then go elsewhere with the intent of getting back later, she
 521 ought to use <KBD>m</KBD> immediately after <KBD>r</KBD>.
 522
 523 </P>
 524 <P>
 525 The command <KBD>x</KBD> (<CODE>po-exchange-location</CODE>) simultaneously
 526 reposition the cursor to the entry associated with the top element of
 527 the stack of saved locations, and replace that top element with the
 528 location of the current entry before the move.  Consequently, repeating
 529 the <KBD>x</KBD> command toggles alternatively between two entries.
 530 For achieving this, the translator will position the cursor on the
 531 first entry, use <KBD>m</KBD>, then position to the second entry, and
 532 merely use <KBD>x</KBD> for making the switch.
 533
 534 </P>
 535
 536
 537 <H2><A NAME="SEC12" HREF="gettext_toc.html#TOC12">Normalizing Strings in Entries</A></H2>
 538
 539 <P>
 540 There are many different ways for encoding a particular string into a
 541 PO file entry, because there are so many different ways to split and
 542 quote multi-line strings, and even, to represent special characters
 543 by backslahsed escaped sequences.  Some features of PO mode rely on
 544 the ability for PO mode to scan an already existing PO file for a
 545 particular string encoded into the <CODE>msgid</CODE> field of some entry.
 546 Even if PO mode has internally all the built-in machinery for
 547 implementing this recognition easily, doing it fast is technically
 548 difficult.  To facilitate a solution to this efficiency problem,
 549 we decided on a canonical representation for strings.
 550
 551 </P>
 552 <P>
 553 A conventional representation of strings in a PO file is currently
 554 under discussion, and PO mode experiments with a canonical representation.
 555 Having both <CODE>xgettext</CODE> and PO mode converging towards a uniform
 556 way of representing equivalent strings would be useful, as the internal
 557 normalization needed by PO mode could be automatically satisfied
 558 when using <CODE>xgettext</CODE> from GNU <CODE>gettext</CODE>.  An explicit
 559 PO mode normalization should then be only necessary for PO files
 560 imported from elsewhere, or for when the convention itself evolves.
 561
 562 </P>
 563 <P>
 564 So, for achieving normalization of at least the strings of a given
 565 PO file needing a canonical representation, the following PO mode
 566 command is available:
 567
 568 </P>
 569 <DL COMPACT>
 570
 571 <DT><KBD>M-x po-normalize</KBD>
 572 <DD>
 573 Tidy the whole PO file by making entries more uniform.
 574
 575 </DL>
 576
 577 <P>
 578 The special command <KBD>M-x po-normalize</KBD>, which has no associate
 579 keys, revises all entries, ensuring that strings of both original
 580 and translated entries use uniform internal quoting in the PO file.
 581 It also removes any crumb after the last entry.  This command may be
 582 useful for PO files freshly imported from elsewhere, or if we ever
 583 improve on the canonical quoting format we use.  This canonical format
 584 is not only meant for getting cleaner PO files, but also for greatly
 585 speeding up <CODE>msgid</CODE> string lookup for some other PO mode commands.
 586
 587 </P>
 588 <P>
 589 <KBD>M-x po-normalize</KBD> presently makes three passes over the entries.
 590 The first implements heuristics for converting PO files for GNU
 591 <CODE>gettext</CODE> 0.6 and earlier, in which <CODE>msgid</CODE> and <CODE>msgstr</CODE>
 592 fields were using K&#38;R style C string syntax for multi-line strings.
 593 These heuristics may fail for comments not related to obsolete
 594 entries and ending with a backslash; they also depend on subsequent
 595 passes for finalizing the proper commenting of continued lines for
 596 obsolete entries.  This first pass might disappear once all oldish PO
 597 files would have been adjusted.  The second and third pass normalize
 598 all <CODE>msgid</CODE> and <CODE>msgstr</CODE> strings respectively.  They also
 599 clean out those trailing backslashes used by XView's <CODE>msgfmt</CODE>
 600 for continued lines.
 601
 602 </P>
 603 <P>
 604 Having such an explicit normalizing command allows for importing PO
 605 files from other sources, but also eases the evolution of the current
 606 convention, evolution driven mostly by aesthetic concerns, as of now.
 607 It is easy to make suggested adjustments at a later time, as the
 608 normalizing command and eventually, other GNU <CODE>gettext</CODE> tools
 609 should greatly automate conformance.  A description of the canonical
 610 string format is given below, for the particular benefit of those not
 611 having GNU Emacs handy, and who would nevertheless want to handcraft
 612 their PO files in nice ways.
 613
 614 </P>
 615 <P>
 616 Right now, in PO mode, strings are single line or multi-line.  A string
 617 goes multi-line if and only if it has <EM>embedded</EM> newlines, that
 618 is, if it matches <SAMP>`[^\n]\n+[^\n]'</SAMP>.  So, we would have:
 619
 620 </P>
 621
 622 <PRE>
 623 msgstr "\n\nHello, world!\n\n\n"
 624 </PRE>
 625
 626 <P>
 627 but, replacing the space by a newline, this becomes:
 628
 629 </P>
 630
 631 <PRE>
 632 msgstr ""
 633 "\n"
 634 "\n"
 635 "Hello,\n"
 636 "world!\n"
 637 "\n"
 638 "\n"
 639 </PRE>
 640
 641 <P>
 642 We are deliberately using a caricatural example, here, to make the
 643 point clearer.  Usually, multi-lines are not that bad looking.
 644 It is probable that we will implement the following suggestion.
 645 We might lump together all initial newlines into the empty string,
 646 and also all newlines introducing empty lines (that is, for <VAR>n</VAR>
 647 &#62; 1, the <VAR>n</VAR>-1'th last newlines would go together on a separate
 648 string), so making the previous example appear:
 649
 650 </P>
 651
 652 <PRE>
 653 msgstr "\n\n"
 654 "Hello,\n"
 655 "world!\n"
 656 "\n\n"
 657 </PRE>
 658
 659 <P>
 660 There are a few yet undecided little points about string normalization,
 661 to be documented in this manual, once these questions settle.
 662
 663 </P>
 664 <P><HR><P>
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