src/buffer_funcs.cpp

   1 /**
   2  * \file buffer_funcs.cpp
   3  * This file is part of LyX, the document processor.
   4  * Licence details can be found in the file COPYING.
   5  *
   6  * \author Lars Gullik Bjønnes
   7  * \author Alfredo Braunstein
   8  *
   9  * Full author contact details are available in file CREDITS.
  10  *
  11  */
  12
  13 #include <config.h>
  14
  15 #include "buffer_funcs.h"
  16 #include "Buffer.h"
  17 #include "BufferList.h"
  18 #include "BufferParams.h"
  19 #include "DocIterator.h"
  20 #include "Counters.h"
  21 #include "ErrorList.h"
  22 #include "Floating.h"
  23 #include "FloatList.h"
  24 #include "gettext.h"
  25 #include "Language.h"
  26 #include "LaTeX.h"
  27 #include "TextClass.h"
  28 #include "Paragraph.h"
  29 #include "paragraph_funcs.h"
  30 #include "ParagraphList.h"
  31 #include "ParagraphParameters.h"
  32 #include "ParIterator.h"
  33 #include "LyXVC.h"
  34 #include "TexRow.h"
  35 #include "TocBackend.h"
  36 #include "VCBackend.h"
  37
  38 #include "frontends/alert.h"
  39
  40 #include "insets/InsetBibitem.h"
  41 #include "insets/InsetCaption.h"
  42 #include "insets/InsetInclude.h"
  43 #include "insets/InsetTabular.h"
  44
  45 #include "support/filetools.h"
  46 #include "support/fs_extras.h"
  47 #include "support/lyxlib.h"
  48
  49 #include <boost/bind.hpp>
  50 #include <boost/filesystem/operations.hpp>
  51
  52
  53 namespace lyx {
  54
  55 using namespace std;
  56
  57 using support::bformat;
  58 using support::FileName;
  59 using support::libFileSearch;
  60 using support::makeAbsPath;
  61 using support::makeDisplayPath;
  62 using support::onlyFilename;
  63 using support::onlyPath;
  64 using support::unlink;
  65
  66 using std::min;
  67 using std::string;
  68
  69 namespace Alert = frontend::Alert;
  70 namespace fs = boost::filesystem;
  71
  72 namespace {
  73
  74 bool readFile(Buffer * const b, FileName const & s)
  75 {
  76         BOOST_ASSERT(b);
  77
  78         // File information about normal file
  79         if (!fs::exists(s.toFilesystemEncoding())) {
  80                 docstring const file = makeDisplayPath(s.absFilename(), 50);
  81                 docstring text = bformat(_("The specified document\n%1$s"
  82                                                      "\ncould not be read."), file);
  83                 Alert::error(_("Could not read document"), text);
  84                 return false;
  85         }
  86
  87         // Check if emergency save file exists and is newer.
  88         FileName const e(s.absFilename() + ".emergency");
  89
  90         if (fs::exists(e.toFilesystemEncoding()) &&
  91             fs::exists(s.toFilesystemEncoding()) &&
  92             fs::last_write_time(e.toFilesystemEncoding()) > fs::last_write_time(s.toFilesystemEncoding()))
  93         {
  94                 docstring const file = makeDisplayPath(s.absFilename(), 20);
  95                 docstring const text =
  96                         bformat(_("An emergency save of the document "
  97                                   "%1$s exists.\n\n"
  98                                                "Recover emergency save?"), file);
  99                 switch (Alert::prompt(_("Load emergency save?"), text, 0, 2,
 100                                       _("&Recover"),  _("&Load Original"),
 101                                       _("&Cancel")))
 102                 {
 103                 case 0:
 104                         // the file is not saved if we load the emergency file.
 105                         b->markDirty();
 106                         return b->readFile(e);
 107                 case 1:
 108                         break;
 109                 default:
 110                         return false;
 111                 }
 112         }
 113
 114         // Now check if autosave file is newer.
 115         FileName const a(onlyPath(s.absFilename()) + '#' + onlyFilename(s.absFilename()) + '#');
 116
 117         if (fs::exists(a.toFilesystemEncoding()) &&
 118             fs::exists(s.toFilesystemEncoding()) &&
 119             fs::last_write_time(a.toFilesystemEncoding()) > fs::last_write_time(s.toFilesystemEncoding()))
 120         {
 121                 docstring const file = makeDisplayPath(s.absFilename(), 20);
 122                 docstring const text =
 123                         bformat(_("The backup of the document "
 124                                   "%1$s is newer.\n\nLoad the "
 125                                                "backup instead?"), file);
 126                 switch (Alert::prompt(_("Load backup?"), text, 0, 2,
 127                                       _("&Load backup"), _("Load &original"),
 128                                       _("&Cancel") ))
 129                 {
 130                 case 0:
 131                         // the file is not saved if we load the autosave file.
 132                         b->markDirty();
 133                         return b->readFile(a);
 134                 case 1:
 135                         // Here we delete the autosave
 136                         unlink(a);
 137                         break;
 138                 default:
 139                         return false;
 140                 }
 141         }
 142         return b->readFile(s);
 143 }
 144
 145
 146 } // namespace anon
 147
 148
 149
 150 bool loadLyXFile(Buffer * b, FileName const & s)
 151 {
 152         BOOST_ASSERT(b);
 153
 154         if (fs::is_readable(s.toFilesystemEncoding())) {
 155                 if (readFile(b, s)) {
 156                         b->lyxvc().file_found_hook(s);
 157                         if (!fs::is_writable(s.toFilesystemEncoding()))
 158                                 b->setReadonly(true);
 159                         return true;
 160                 }
 161         } else {
 162                 docstring const file = makeDisplayPath(s.absFilename(), 20);
 163                 // Here we probably should run
 164                 if (LyXVC::file_not_found_hook(s)) {
 165                         docstring const text =
 166                                 bformat(_("Do you want to retrieve the document"
 167                                                        " %1$s from version control?"), file);
 168                         int const ret = Alert::prompt(_("Retrieve from version control?"),
 169                                 text, 0, 1, _("&Retrieve"), _("&Cancel"));
 170
 171                         if (ret == 0) {
 172                                 // How can we know _how_ to do the checkout?
 173                                 // With the current VC support it has to be,
 174                                 // a RCS file since CVS do not have special ,v files.
 175                                 RCS::retrieve(s);
 176                                 return loadLyXFile(b, s);
 177                         }
 178                 }
 179         }
 180         return false;
 181 }
 182
 183 // FIXME newFile() should probably be a member method of Application...
 184 Buffer * newFile(string const & filename, string const & templatename,
 185                  bool const isNamed)
 186 {
 187         // get a free buffer
 188         Buffer * b = theBufferList().newBuffer(filename);
 189         BOOST_ASSERT(b);
 190
 191         FileName tname;
 192         // use defaults.lyx as a default template if it exists.
 193         if (templatename.empty())
 194                 tname = libFileSearch("templates", "defaults.lyx");
 195         else
 196                 tname = makeAbsPath(templatename);
 197
 198         if (!tname.empty()) {
 199                 if (!b->readFile(tname)) {
 200                         docstring const file = makeDisplayPath(tname.absFilename(), 50);
 201                         docstring const text  = bformat(
 202                                 _("The specified document template\n%1$s\ncould not be read."),
 203                                 file);
 204                         Alert::error(_("Could not read template"), text);
 205                         theBufferList().release(b);
 206                         return 0;
 207                 }
 208         }
 209
 210         if (!isNamed) {
 211                 b->setUnnamed();
 212                 b->setFileName(filename);
 213         }
 214
 215         b->setReadonly(false);
 216         b->fully_loaded(true);
 217
 218         return b;
 219 }
 220
 221
 222 void bufferErrors(Buffer const & buf, TeXErrors const & terr,
 223                                   ErrorList & errorList)
 224 {
 225         TeXErrors::Errors::const_iterator cit = terr.begin();
 226         TeXErrors::Errors::const_iterator end = terr.end();
 227
 228         for (; cit != end; ++cit) {
 229                 int id_start = -1;
 230                 int pos_start = -1;
 231                 int errorrow = cit->error_in_line;
 232                 bool found = buf.texrow().getIdFromRow(errorrow, id_start,
 233                                                        pos_start);
 234                 int id_end = -1;
 235                 int pos_end = -1;
 236                 do {
 237                         ++errorrow;
 238                         found = buf.texrow().getIdFromRow(errorrow, id_end,
 239                                                           pos_end);
 240                 } while (found && id_start == id_end && pos_start == pos_end);
 241
 242                 errorList.push_back(ErrorItem(cit->error_desc,
 243                         cit->error_text, id_start, pos_start, pos_end));
 244         }
 245 }
 246
 247
 248 string const bufferFormat(Buffer const & buffer)
 249 {
 250         if (buffer.isDocBook())
 251                 return "docbook";
 252         else if (buffer.isLiterate())
 253                 return "literate";
 254         else
 255                 return "latex";
 256 }
 257
 258
 259 int countWords(DocIterator const & from, DocIterator const & to)
 260 {
 261         int count = 0;
 262         bool inword = false;
 263         for (DocIterator dit = from ; dit != to ; dit.forwardPos()) {
 264                 // Copied and adapted from isLetter() in ControlSpellChecker
 265                 if (dit.inTexted()
 266                     && dit.pos() != dit.lastpos()
 267                     && dit.paragraph().isLetter(dit.pos())
 268                     && !dit.paragraph().isDeleted(dit.pos())) {
 269                         if (!inword) {
 270                                 ++count;
 271                                 inword = true;
 272                         }
 273                 } else if (inword)
 274                         inword = false;
 275         }
 276
 277         return count;
 278 }
 279
 280
 281 namespace {
 282
 283 depth_type getDepth(DocIterator const & it)
 284 {
 285         depth_type depth = 0;
 286         for (size_t i = 0 ; i < it.depth() ; ++i)
 287                 if (!it[i].inset().inMathed())
 288                         depth += it[i].paragraph().getDepth() + 1;
 289         // remove 1 since the outer inset does not count
 290         return depth - 1;
 291 }
 292
 293 depth_type getItemDepth(ParIterator const & it)
 294 {
 295         Paragraph const & par = *it;
 296         LYX_LABEL_TYPES const labeltype = par.layout()->labeltype;
 297
 298         if (labeltype != LABEL_ENUMERATE && labeltype != LABEL_ITEMIZE)
 299                 return 0;
 300
 301         // this will hold the lowest depth encountered up to now.
 302         depth_type min_depth = getDepth(it);
 303         ParIterator prev_it = it;
 304         while (true) {
 305                 if (prev_it.pit())
 306                         --prev_it.top().pit();
 307                 else {
 308                         // start of nested inset: go to outer par
 309                         prev_it.pop_back();
 310                         if (prev_it.empty()) {
 311                                 // start of document: nothing to do
 312                                 return 0;
 313                         }
 314                 }
 315
 316                 // We search for the first paragraph with same label
 317                 // that is not more deeply nested.
 318                 Paragraph & prev_par = *prev_it;
 319                 depth_type const prev_depth = getDepth(prev_it);
 320                 if (labeltype == prev_par.layout()->labeltype) {
 321                         if (prev_depth < min_depth) {
 322                                 return prev_par.itemdepth + 1;
 323                         }
 324                         else if (prev_depth == min_depth) {
 325                                 return prev_par.itemdepth;
 326                         }
 327                 }
 328                 min_depth = std::min(min_depth, prev_depth);
 329                 // small optimization: if we are at depth 0, we won't
 330                 // find anything else
 331                 if (prev_depth == 0) {
 332                         return 0;
 333                 }
 334         }
 335 }
 336
 337
 338 bool needEnumCounterReset(ParIterator const & it)
 339 {
 340         Paragraph const & par = *it;
 341         BOOST_ASSERT(par.layout()->labeltype == LABEL_ENUMERATE);
 342         depth_type const cur_depth = par.getDepth();
 343         ParIterator prev_it = it;
 344         while (prev_it.pit()) {
 345                 --prev_it.top().pit();
 346                 Paragraph const & prev_par = *prev_it;
 347                 if (prev_par.getDepth() <= cur_depth)
 348                         return  prev_par.layout()->labeltype != LABEL_ENUMERATE;
 349         }
 350         // start of nested inset: reset
 351         return true;
 352 }
 353
 354
 355 void setCaptionLabels(Inset & inset, string const & type,
 356                 docstring const label, Counters & counters)
 357 {
 358         Text * text = inset.getText(0);
 359         if (!text)
 360                 return;
 361
 362         ParagraphList & pars = text->paragraphs();
 363         if (pars.empty())
 364                 return;
 365
 366         docstring const counter = from_ascii(type);
 367
 368         ParagraphList::iterator p = pars.begin();
 369         for (; p != pars.end(); ++p) {
 370                 InsetList::iterator it2 = p->insetlist.begin();
 371                 InsetList::iterator end2 = p->insetlist.end();
 372                 // Any caption within this float should have the same
 373                 // label prefix but different numbers.
 374                 for (; it2 != end2; ++it2) {
 375                         Inset & icap = *it2->inset;
 376                         // Look deeper just in case.
 377                         setCaptionLabels(icap, type, label, counters);
 378                         if (icap.lyxCode() == Inset::CAPTION_CODE) {
 379                                 // We found a caption!
 380                                 counters.step(counter);
 381                                 int number = counters.value(counter);
 382                                 InsetCaption & ic = static_cast<InsetCaption &>(icap);
 383                                 ic.setType(type);
 384                                 ic.setCount(number);
 385                                 ic.setCustomLabel(label);
 386                         }
 387                 }
 388         }
 389 }
 390
 391
 392 void setCaptions(Paragraph & par, TextClass const & textclass)
 393 {
 394         if (par.insetlist.empty())
 395                 return;
 396
 397         Counters & counters = textclass.counters();
 398
 399         InsetList::iterator it = par.insetlist.begin();
 400         InsetList::iterator end = par.insetlist.end();
 401         for (; it != end; ++it) {
 402                 Inset & inset = *it->inset;
 403                 if (inset.lyxCode() == Inset::FLOAT_CODE
 404                         || inset.lyxCode() == Inset::WRAP_CODE) {
 405                         docstring const name = inset.name();
 406                         if (name.empty())
 407                                 continue;
 408
 409                         Floating const & fl = textclass.floats().getType(to_ascii(name));
 410                         // FIXME UNICODE
 411                         string const & type = fl.type();
 412                         docstring const label = from_utf8(fl.name());
 413                         setCaptionLabels(inset, type, label, counters);
 414                 }
 415                 else if (inset.lyxCode() == Inset::TABULAR_CODE
 416                         &&  static_cast<InsetTabular &>(inset).tabular.isLongTabular()) {
 417                         // FIXME: are "table" and "Table" the correct type and label?
 418                         setCaptionLabels(inset, "table", from_ascii("Table"), counters);
 419                 }
 420         }
 421 }
 422
 423 // set the label of a paragraph. This includes the counters.
 424 void setLabel(Buffer const & buf, ParIterator & it, TextClass const & textclass)
 425 {
 426         Paragraph & par = *it;
 427         Layout_ptr const & layout = par.layout();
 428         Counters & counters = textclass.counters();
 429
 430         if (it.pit() == 0) {
 431                 par.params().appendix(par.params().startOfAppendix());
 432         } else {
 433                 par.params().appendix(it.plist()[it.pit() - 1].params().appendix());
 434                 if (!par.params().appendix() &&
 435                     par.params().startOfAppendix()) {
 436                         par.params().appendix(true);
 437                         textclass.counters().reset();
 438                 }
 439         }
 440
 441         // Compute the item depth of the paragraph
 442         par.itemdepth = getItemDepth(it);
 443
 444         if (layout->margintype == MARGIN_MANUAL) {
 445                 if (par.params().labelWidthString().empty())
 446                         par.params().labelWidthString(par.translateIfPossible(layout->labelstring(), buf.params()));
 447         } else {
 448                 par.params().labelWidthString(docstring());
 449         }
 450
 451         // Optimisation: setLabel() can be called for each for each
 452         // paragraph of the document. So we make the string static to
 453         // avoid the repeated instanciation.
 454         static docstring itemlabel;
 455
 456         // is it a layout that has an automatic label?
 457         if (layout->labeltype == LABEL_COUNTER) {
 458                 if (layout->toclevel <= buf.params().secnumdepth
 459                     && (layout->latextype != LATEX_ENVIRONMENT
 460                         || isFirstInSequence(it.pit(), it.plist()))) {
 461                         counters.step(layout->counter);
 462                         par.params().labelString(
 463                                 par.expandLabel(layout, buf.params()));
 464                 } else
 465                         par.params().labelString(docstring());
 466
 467         } else if (layout->labeltype == LABEL_ITEMIZE) {
 468                 // At some point of time we should do something more
 469                 // clever here, like:
 470                 //   par.params().labelString(
 471                 //    buf.params().user_defined_bullet(par.itemdepth).getText());
 472                 // for now, use a simple hardcoded label
 473                 switch (par.itemdepth) {
 474                 case 0:
 475                         itemlabel = char_type(0x2022);
 476                         break;
 477                 case 1:
 478                         itemlabel = char_type(0x2013);
 479                         break;
 480                 case 2:
 481                         itemlabel = char_type(0x2217);
 482                         break;
 483                 case 3:
 484                         itemlabel = char_type(0x2219); // or 0x00b7
 485                         break;
 486                 }
 487                 par.params().labelString(itemlabel);
 488
 489         } else if (layout->labeltype == LABEL_ENUMERATE) {
 490                 // FIXME
 491                 // Yes I know this is a really, really! bad solution
 492                 // (Lgb)
 493                 docstring enumcounter = from_ascii("enum");
 494
 495                 switch (par.itemdepth) {
 496                 case 2:
 497                         enumcounter += 'i';
 498                 case 1:
 499                         enumcounter += 'i';
 500                 case 0:
 501                         enumcounter += 'i';
 502                         break;
 503                 case 3:
 504                         enumcounter += "iv";
 505                         break;
 506                 default:
 507                         // not a valid enumdepth...
 508                         break;
 509                 }
 510
 511                 // Maybe we have to reset the enumeration counter.
 512                 if (needEnumCounterReset(it))
 513                         counters.reset(enumcounter);
 514
 515                 counters.step(enumcounter);
 516
 517                 string format;
 518
 519                 switch (par.itemdepth) {
 520                 case 0:
 521                         format = N_("\\arabic{enumi}.");
 522                         break;
 523                 case 1:
 524                         format = N_("(\\alph{enumii})");
 525                         break;
 526                 case 2:
 527                         format = N_("\\roman{enumiii}.");
 528                         break;
 529                 case 3:
 530                         format = N_("\\Alph{enumiv}.");
 531                         break;
 532                 default:
 533                         // not a valid enumdepth...
 534                         break;
 535                 }
 536
 537                 par.params().labelString(counters.counterLabel(
 538                         par.translateIfPossible(from_ascii(format), buf.params())));
 539
 540         } else if (layout->labeltype == LABEL_BIBLIO) {// ale970302
 541                 counters.step(from_ascii("bibitem"));
 542                 int number = counters.value(from_ascii("bibitem"));
 543                 if (par.bibitem())
 544                         par.bibitem()->setCounter(number);
 545
 546                 par.params().labelString(
 547                         par.translateIfPossible(layout->labelstring(), buf.params()));
 548                 // In biblio shouldn't be following counters but...
 549         } else if (layout->labeltype == LABEL_SENSITIVE) {
 550                 // Search for the first float or wrap inset in the iterator
 551                 size_t i = it.depth();
 552                 Inset * in = 0;
 553                 while (i > 0) {
 554                         --i;
 555                         Inset::Code const code = it[i].inset().lyxCode();
 556                         if (code == Inset::FLOAT_CODE ||
 557                             code == Inset::WRAP_CODE) {
 558                                 in = &it[i].inset();
 559                                 break;
 560                         }
 561                 }
 562                 // FIXME Can Inset::name() return an empty name for wide or
 563                 // float insets? If not we can put the definition of type
 564                 // inside the if (in) clause and use that instead of
 565                 // if (!type.empty()).
 566                 docstring type;
 567                 if (in)
 568                         type = in->name();
 569
 570                 if (!type.empty()) {
 571                         Floating const & fl = textclass.floats().getType(to_ascii(type));
 572                         // FIXME UNICODE
 573                         counters.step(from_ascii(fl.type()));
 574
 575                         // Doesn't work... yet.
 576                         par.params().labelString(par.translateIfPossible(
 577                                 bformat(from_ascii("%1$s #:"), from_utf8(fl.name())),
 578                                 buf.params()));
 579                 } else {
 580                         // par->SetLayout(0);
 581                         par.params().labelString(par.translateIfPossible(
 582                                 layout->labelstring(), buf.params()));
 583                 }
 584
 585         } else if (layout->labeltype == LABEL_NO_LABEL)
 586                 par.params().labelString(docstring());
 587         else
 588                 par.params().labelString(
 589                         par.translateIfPossible(layout->labelstring(), buf.params()));
 590 }
 591
 592 } // anon namespace
 593
 594
 595 bool updateCurrentLabel(Buffer const & buf,
 596         ParIterator & it)
 597 {
 598     if (it == par_iterator_end(buf.inset()))
 599         return false;
 600
 601 //      if (it.lastpit == 0 && Text::isMainText(buf))
 602 //              return false;
 603
 604         switch (it->layout()->labeltype) {
 605
 606         case LABEL_NO_LABEL:
 607         case LABEL_MANUAL:
 608         case LABEL_BIBLIO:
 609         case LABEL_TOP_ENVIRONMENT:
 610         case LABEL_CENTERED_TOP_ENVIRONMENT:
 611         case LABEL_STATIC:
 612         case LABEL_ITEMIZE:
 613                 setLabel(buf, it, buf.params().getTextClass());
 614                 return true;
 615
 616         case LABEL_SENSITIVE:
 617         case LABEL_COUNTER:
 618         // do more things with enumerate later
 619         case LABEL_ENUMERATE:
 620                 return false;
 621         }
 622
 623         // This is dead code which get rid of a warning:
 624         return true;
 625 }
 626
 627
 628 void updateLabels(Buffer const & buf,
 629         ParIterator & from, ParIterator & to, bool childonly)
 630 {
 631         for (ParIterator it = from; it != to; ++it) {
 632                 if (it.pit() > it.lastpit())
 633                         return;
 634                 if (!updateCurrentLabel (buf, it)) {
 635                         updateLabels(buf, childonly);
 636                         return;
 637                 }
 638         }
 639 }
 640
 641
 642 void updateLabels(Buffer const & buf, ParIterator & iter, bool childonly)
 643 {
 644         if (updateCurrentLabel(buf, iter))
 645                 return;
 646
 647         updateLabels(buf, childonly);
 648 }
 649
 650
 651 void updateLabels(Buffer const & buf, bool childonly)
 652 {
 653         // Use the master text class also for child documents
 654         TextClass const & textclass = buf.params().getTextClass();
 655
 656         if (!childonly) {
 657                 // If this is a child document start with the master
 658                 Buffer const * const master = buf.getMasterBuffer();
 659                 if (master != &buf) {
 660                         updateLabels(*master);
 661                         return;
 662                 }
 663
 664                 // start over the counters
 665                 textclass.counters().reset();
 666         }
 667
 668         ParIterator const end = par_iterator_end(buf.inset());
 669
 670         for (ParIterator it = par_iterator_begin(buf.inset()); it != end; ++it) {
 671                 // reduce depth if necessary
 672                 if (it.pit()) {
 673                         Paragraph const & prevpar = it.plist()[it.pit() - 1];
 674                         it->params().depth(min(it->params().depth(),
 675                                                prevpar.getMaxDepthAfter()));
 676                 } else
 677                         it->params().depth(0);
 678
 679                 // set the counter for this paragraph
 680                 setLabel(buf, it, textclass);
 681
 682                 // It is better to set the captions after setLabel because
 683                 // the caption number might need the section number in the
 684                 // future.
 685                 setCaptions(*it, textclass);
 686
 687                 // Now included docs
 688                 InsetList::const_iterator iit = it->insetlist.begin();
 689                 InsetList::const_iterator end = it->insetlist.end();
 690                 for (; iit != end; ++iit) {
 691                         if (iit->inset->lyxCode() == Inset::INCLUDE_CODE)
 692                                 static_cast<InsetInclude const *>(iit->inset)
 693                                         ->updateLabels(buf);
 694                 }
 695         }
 696
 697         Buffer & cbuf = const_cast<Buffer &>(buf);
 698         cbuf.tocBackend().update();
 699         cbuf.structureChanged();
 700 }
 701
 702
 703 void checkBufferStructure(Buffer & buffer, ParIterator const & par_it)
 704 {
 705         if (par_it->layout()->labeltype == LABEL_COUNTER
 706                 && par_it->layout()->toclevel != Layout::NOT_IN_TOC) {
 707                 buffer.tocBackend().updateItem(par_it);
 708                 buffer.structureChanged();
 709         }
 710 }
 711
 712 } // namespace lyx