src/Lexer.cpp

   1 /**
   2  * \file Lexer.cpp
   3  * This file is part of LyX, the document processor.
   4  * Licence details can be found in the file COPYING.
   5  *
   6  * \author Alejandro Aguilar Sierra
   7  * \author Lars Gullik Bjønnes
   8  * \author Jean-Marc Lasgouttes
   9  * \author John Levon
  10  *
  11  * Full author contact details are available in file CREDITS.
  12  */
  13
  14 #include <config.h>
  15
  16 #include "Lexer.h"
  17
  18 #include "support/convert.h"
  19 #include "support/debug.h"
  20 #include "support/FileName.h"
  21 #include "support/filetools.h"
  22 #include "support/gzstream.h"
  23 #include "support/lstrings.h"
  24 #include "support/lyxalgo.h"
  25 #include "support/types.h"
  26
  27 #include <functional>
  28 #include <istream>
  29 #include <stack>
  30 #include <vector>
  31
  32 using namespace std;
  33 using namespace lyx::support;
  34
  35 namespace lyx {
  36
  37 //////////////////////////////////////////////////////////////////////
  38 //
  39 // Lexer::Pimpl
  40 //
  41 //////////////////////////////////////////////////////////////////////
  42
  43
  44 ///
  45 class Lexer::Pimpl {
  46 public:
  47         ///
  48         Pimpl(LexerKeyword * tab, int num);
  49         ///
  50         string const getString() const;
  51         ///
  52         docstring const getDocString() const;
  53         ///
  54         void printError(string const & message) const;
  55         ///
  56         void printTable(ostream & os);
  57         ///
  58         void pushTable(LexerKeyword * tab, int num);
  59         ///
  60         void popTable();
  61         ///
  62         bool setFile(FileName const & filename);
  63         ///
  64         void setStream(istream & i);
  65         ///
  66         void setCommentChar(char c);
  67         ///
  68         bool next(bool esc = false);
  69         ///
  70         int searchKeyword(char const * const tag) const;
  71         ///
  72         int lex();
  73         ///
  74         bool eatLine();
  75         ///
  76         bool nextToken();
  77         /// test if there is a pushed token or the stream is ok
  78         bool inputAvailable();
  79         ///
  80         void pushToken(string const &);
  81         /// fb_ is only used to open files, the stream is accessed through is.
  82         filebuf fb_;
  83
  84         /// gz_ is only used to open files, the stream is accessed through is.
  85         gz::gzstreambuf gz_;
  86
  87         /// the stream that we use.
  88         istream is;
  89         ///
  90         string name;
  91         ///
  92         LexerKeyword * table;
  93         ///
  94         int no_items;
  95         ///
  96         string buff;
  97         ///
  98         int status;
  99         ///
 100         int lineno;
 101         ///
 102         string pushTok;
 103         ///
 104         char commentChar;
 105         /// used for error messages
 106         string context;
 107 private:
 108         /// non-copyable
 109         Pimpl(Pimpl const &);
 110         void operator=(Pimpl const &);
 111
 112         ///
 113         void verifyTable();
 114         ///
 115         class PushedTable {
 116         public:
 117                 ///
 118                 PushedTable()
 119                         : table_elem(0), table_siz(0) {}
 120                 ///
 121                 PushedTable(LexerKeyword * ki, int siz)
 122                         : table_elem(ki), table_siz(siz) {}
 123                 ///
 124                 LexerKeyword * table_elem;
 125                 ///
 126                 int table_siz;
 127         };
 128         ///
 129         stack<PushedTable> pushed;
 130 };
 131
 132
 133
 134 namespace {
 135
 136 class CompareTags
 137         : public binary_function<LexerKeyword, LexerKeyword, bool> {
 138 public:
 139         // used by lower_bound, sort and sorted
 140         bool operator()(LexerKeyword const & a, LexerKeyword const & b) const
 141         {
 142                 // we use the ascii version, because in turkish, 'i'
 143                 // is not the lowercase version of 'I', and thus
 144                 // turkish locale breaks parsing of tags.
 145                 return compare_ascii_no_case(a.tag, b.tag) < 0;
 146         }
 147 };
 148
 149 } // end of anon namespace
 150
 151
 152 Lexer::Pimpl::Pimpl(LexerKeyword * tab, int num)
 153         : is(&fb_), table(tab), no_items(num),
 154           status(0), lineno(0), commentChar('#')
 155 {
 156         verifyTable();
 157 }
 158
 159
 160 string const Lexer::Pimpl::getString() const
 161 {
 162         return buff;
 163 }
 164
 165
 166 docstring const Lexer::Pimpl::getDocString() const
 167 {
 168         return from_utf8(buff);
 169 }
 170
 171
 172 void Lexer::Pimpl::printError(string const & message) const
 173 {
 174         string const tmpmsg = subst(message, "$$Token", getString());
 175         lyxerr << "LyX: " << tmpmsg << " [around line " << lineno
 176                 << " of file " << to_utf8(makeDisplayPath(name))
 177                 << " current token: '" << getString() << "'"
 178                 << " context: '" << context << "']" << endl;
 179 }
 180
 181
 182 void Lexer::Pimpl::printTable(ostream & os)
 183 {
 184         os << "\nNumber of tags: " << no_items << endl;
 185         for (int i= 0; i < no_items; ++i)
 186                 os << "table[" << i
 187                    << "]:  tag: `" << table[i].tag
 188                    << "'  code:" << table[i].code << '\n';
 189         os.flush();
 190 }
 191
 192
 193 void Lexer::Pimpl::verifyTable()
 194 {
 195         // Check if the table is sorted and if not, sort it.
 196         if (table
 197             && !lyx::sorted(table, table + no_items, CompareTags())) {
 198                 lyxerr << "The table passed to Lexer is not sorted!\n"
 199                        << "Tell the developers to fix it!" << endl;
 200                 // We sort it anyway to avoid problems.
 201                 lyxerr << "\nUnsorted:" << endl;
 202                 printTable(lyxerr);
 203
 204                 sort(table, table + no_items, CompareTags());
 205                 lyxerr << "\nSorted:" << endl;
 206                 printTable(lyxerr);
 207         }
 208 }
 209
 210
 211 void Lexer::Pimpl::pushTable(LexerKeyword * tab, int num)
 212 {
 213         PushedTable tmppu(table, no_items);
 214         pushed.push(tmppu);
 215
 216         table = tab;
 217         no_items = num;
 218
 219         verifyTable();
 220 }
 221
 222
 223 void Lexer::Pimpl::popTable()
 224 {
 225         if (pushed.empty()) {
 226                 lyxerr << "Lexer error: nothing to pop!" << endl;
 227                 return;
 228         }
 229
 230         PushedTable tmp = pushed.top();
 231         pushed.pop();
 232         table = tmp.table_elem;
 233         no_items = tmp.table_siz;
 234 }
 235
 236
 237 bool Lexer::Pimpl::setFile(FileName const & filename)
 238 {
 239         // Check the format of the file.
 240         string const format = filename.guessFormatFromContents();
 241
 242         if (format == "gzip" || format == "zip" || format == "compress") {
 243                 LYXERR(Debug::LYXLEX, "lyxlex: compressed");
 244                 // The check only outputs a debug message, because it triggers
 245                 // a bug in compaq cxx 6.2, where is_open() returns 'true' for
 246                 // a fresh new filebuf.  (JMarc)
 247                 if (gz_.is_open() || istream::off_type(is.tellg()) > -1)
 248                         LYXERR(Debug::LYXLEX, "Error in LyXLex::setFile: "
 249                                 "file or stream already set.");
 250                 gz_.open(filename.toFilesystemEncoding().c_str(), ios::in);
 251                 is.rdbuf(&gz_);
 252                 name = filename.absFilename();
 253                 lineno = 0;
 254                 return gz_.is_open() && is.good();
 255         } else {
 256                 LYXERR(Debug::LYXLEX, "lyxlex: UNcompressed");
 257
 258                 // The check only outputs a debug message, because it triggers
 259                 // a bug in compaq cxx 6.2, where is_open() returns 'true' for
 260                 // a fresh new filebuf.  (JMarc)
 261                 if (fb_.is_open() || istream::off_type(is.tellg()) > 0) {
 262                         LYXERR(Debug::LYXLEX, "Error in Lexer::setFile: "
 263                                 "file or stream already set.");
 264                 }
 265                 fb_.open(filename.toFilesystemEncoding().c_str(), ios::in);
 266                 is.rdbuf(&fb_);
 267                 name = filename.absFilename();
 268                 lineno = 0;
 269                 return fb_.is_open() && is.good();
 270         }
 271 }
 272
 273
 274 void Lexer::Pimpl::setStream(istream & i)
 275 {
 276         if (fb_.is_open() || istream::off_type(is.tellg()) > 0) {
 277                 LYXERR(Debug::LYXLEX, "Error in Lexer::setStream: "
 278                         "file or stream already set.");
 279         }
 280         is.rdbuf(i.rdbuf());
 281         lineno = 0;
 282 }
 283
 284
 285 void Lexer::Pimpl::setCommentChar(char c)
 286 {
 287         commentChar = c;
 288 }
 289
 290
 291 bool Lexer::Pimpl::next(bool esc /* = false */)
 292 {
 293         if (!pushTok.empty()) {
 294                 // There can have been a whole line pushed so
 295                 // we extract the first word and leaves the rest
 296                 // in pushTok. (Lgb)
 297                 if (pushTok[0] == '\\' && pushTok.find(' ') != string::npos) {
 298                         buff.clear();
 299                         pushTok = split(pushTok, buff, ' ');
 300                 } else {
 301                         buff = pushTok;
 302                         pushTok.clear();
 303                 }
 304                 status = LEX_TOKEN;
 305                 return true;
 306         }
 307
 308
 309         unsigned char c = 0; // getc() returns an int
 310         char cc = 0;
 311         status = 0;
 312         while (is && !status) {
 313                 is.get(cc);
 314                 c = cc;
 315
 316                 if (c == commentChar) {
 317                         // Read rest of line (fast :-)
 318 #if 1
 319                         // That is not fast... (Lgb)
 320                         string dummy;
 321                         getline(is, dummy);
 322
 323                         LYXERR(Debug::LYXLEX, "Comment read: `" << c << dummy << '\'');
 324 #else
 325                         // unfortunately ignore is buggy (Lgb)
 326                         is.ignore(100, '\n');
 327 #endif
 328                         ++lineno;
 329                         continue;
 330                 }
 331
 332                 if (c == '\"') {
 333                         buff.clear();
 334
 335                         if (esc) {
 336
 337                                 bool escaped = false;
 338                                 do {
 339                                         escaped = false;
 340                                         is.get(cc);
 341                                         c = cc;
 342                                         if (c == '\r') continue;
 343                                         if (c == '\\') {
 344                                                 // escape the next char
 345                                                 is.get(cc);
 346                                                 c = cc;
 347                                                 if (c == '\"' || c == '\\')
 348                                                         escaped = true;
 349                                                 else
 350                                                         buff.push_back('\\');
 351                                         }
 352                                         buff.push_back(c);
 353
 354                                         if (!escaped && c == '\"')
 355                                                 break;
 356                                 } while (c != '\n' && is);
 357
 358                         } else {
 359
 360                                 do {
 361                                         is.get(cc);
 362                                         c = cc;
 363                                         if (c != '\r')
 364                                                 buff.push_back(c);
 365                                 } while (c != '\"' && c != '\n' && is);
 366
 367                         }
 368
 369                         if (c != '\"') {
 370                                 printError("Missing quote");
 371                                 if (c == '\n')
 372                                         ++lineno;
 373                         }
 374
 375                         buff.resize(buff.size() - 1);
 376                         status = LEX_DATA;
 377                         break;
 378                 }
 379
 380                 if (c == ',')
 381                         continue;              /* Skip ','s */
 382
 383                 // using relational operators with chars other
 384                 // than == and != is not safe. And if it is done
 385                 // the type _have_ to be unsigned. It usually a
 386                 // lot better to use the functions from cctype
 387                 if (c > ' ' && is)  {
 388                         buff.clear();
 389
 390                         do {
 391                                 if (esc && c == '\\') {
 392                                         // escape the next char
 393                                         is.get(cc);
 394                                         c = cc;
 395                                         //escaped = true;
 396                                 }
 397                                 buff.push_back(c);
 398                                 is.get(cc);
 399                                 c = cc;
 400                         } while (c > ' ' && c != ',' && is);
 401                         status = LEX_TOKEN;
 402                 }
 403
 404                 if (c == '\r' && is) {
 405                         // The Windows support has lead to the
 406                         // possibility of "\r\n" at the end of
 407                         // a line.  This will stop LyX choking
 408                         // when it expected to find a '\n'
 409                         is.get(cc);
 410                         c = cc;
 411                 }
 412
 413                 if (c == '\n')
 414                         ++lineno;
 415
 416         }
 417         if (status)
 418                 return true;
 419
 420         status = is.eof() ? LEX_FEOF: LEX_UNDEF;
 421         buff.clear();
 422         return false;
 423 }
 424
 425
 426 int Lexer::Pimpl::searchKeyword(char const * const tag) const
 427 {
 428         LexerKeyword search_tag = { tag, 0 };
 429         LexerKeyword * res =
 430                 lower_bound(table, table + no_items,
 431                             search_tag, CompareTags());
 432         // use the compare_ascii_no_case instead of compare_no_case,
 433         // because in turkish, 'i' is not the lowercase version of 'I',
 434         // and thus turkish locale breaks parsing of tags.
 435         if (res != table + no_items
 436             && !compare_ascii_no_case(res->tag, tag))
 437                 return res->code;
 438         return LEX_UNDEF;
 439 }
 440
 441
 442 int Lexer::Pimpl::lex()
 443 {
 444         //NOTE: possible bug.
 445         if (next() && status == LEX_TOKEN)
 446                 return searchKeyword(getString().c_str());
 447         return status;
 448 }
 449
 450
 451 bool Lexer::Pimpl::eatLine()
 452 {
 453         buff.clear();
 454
 455         unsigned char c = '\0';
 456         char cc = 0;
 457         while (is && c != '\n') {
 458                 is.get(cc);
 459                 c = cc;
 460                 //LYXERR(Debug::LYXLEX, "Lexer::EatLine read char: `" << c << '\'');
 461                 if (c != '\r')
 462                         buff.push_back(c);
 463         }
 464
 465         if (c == '\n') {
 466                 ++lineno;
 467                 buff.resize(buff.size() - 1);
 468                 status = LEX_DATA;
 469                 return true;
 470         } else if (buff.length() > 0) { // last line
 471                 status = LEX_DATA;
 472                 return true;
 473         } else {
 474                 return false;
 475         }
 476 }
 477
 478
 479 bool Lexer::Pimpl::nextToken()
 480 {
 481         if (!pushTok.empty()) {
 482                 // There can have been a whole line pushed so
 483                 // we extract the first word and leaves the rest
 484                 // in pushTok. (Lgb)
 485                 if (pushTok[0] == '\\' && pushTok.find(' ') != string::npos) {
 486                         buff.clear();
 487                         pushTok = split(pushTok, buff, ' ');
 488                 } else {
 489                         buff = pushTok;
 490                         pushTok.clear();
 491                 }
 492                 status = LEX_TOKEN;
 493                 return true;
 494         }
 495
 496         status = 0;
 497         while (is && !status) {
 498                 unsigned char c = 0;
 499                 char cc = 0;
 500                 is.get(cc);
 501                 c = cc;
 502                 if (c >= ' ' && is) {
 503                         buff.clear();
 504
 505                         if (c == '\\') { // first char == '\\'
 506                                 do {
 507                                         buff.push_back(c);
 508                                         is.get(cc);
 509                                         c = cc;
 510                                 } while (c > ' ' && c != '\\' && is);
 511                         } else {
 512                                 do {
 513                                         buff.push_back(c);
 514                                         is.get(cc);
 515                                         c = cc;
 516                                 } while (c >= ' ' && c != '\\' && is);
 517                         }
 518
 519                         if (c == '\\')
 520                                 is.putback(c); // put it back
 521                         status = LEX_TOKEN;
 522                 }
 523
 524                 if (c == '\n')
 525                         ++lineno;
 526
 527         }
 528         if (status)
 529                 return true;
 530
 531         status = is.eof() ? LEX_FEOF: LEX_UNDEF;
 532         buff.clear();
 533         return false;
 534 }
 535
 536
 537 bool Lexer::Pimpl::inputAvailable()
 538 {
 539         return is.good();
 540 }
 541
 542
 543 void Lexer::Pimpl::pushToken(string const & pt)
 544 {
 545         pushTok = pt;
 546 }
 547
 548
 549
 550
 551 //////////////////////////////////////////////////////////////////////
 552 //
 553 // Lexer
 554 //
 555 //////////////////////////////////////////////////////////////////////
 556
 557 Lexer::Lexer()
 558         : pimpl_(new Pimpl(0, 0))
 559 {}
 560
 561
 562 void Lexer::init(LexerKeyword * tab, int num)
 563 {
 564          pimpl_ = new Pimpl(tab, num);
 565 }
 566
 567
 568 Lexer::~Lexer()
 569 {
 570         delete pimpl_;
 571 }
 572
 573
 574 bool Lexer::isOK() const
 575 {
 576         return pimpl_->inputAvailable();
 577 }
 578
 579
 580 void Lexer::setLineNumber(int l)
 581 {
 582         pimpl_->lineno = l;
 583 }
 584
 585
 586 int Lexer::lineNumber() const
 587 {
 588         return pimpl_->lineno;
 589 }
 590
 591
 592 istream & Lexer::getStream()
 593 {
 594         return pimpl_->is;
 595 }
 596
 597
 598 void Lexer::pushTable(LexerKeyword * tab, int num)
 599 {
 600         pimpl_->pushTable(tab, num);
 601 }
 602
 603
 604 void Lexer::popTable()
 605 {
 606         pimpl_->popTable();
 607 }
 608
 609
 610 void Lexer::printTable(ostream & os)
 611 {
 612         pimpl_->printTable(os);
 613 }
 614
 615
 616 void Lexer::printError(string const & message) const
 617 {
 618         pimpl_->printError(message);
 619 }
 620
 621
 622 bool Lexer::setFile(FileName const & filename)
 623 {
 624         return pimpl_->setFile(filename);
 625 }
 626
 627
 628 void Lexer::setStream(istream & i)
 629 {
 630         pimpl_->setStream(i);
 631 }
 632
 633
 634 void Lexer::setCommentChar(char c)
 635 {
 636         pimpl_->setCommentChar(c);
 637 }
 638
 639
 640 int Lexer::lex()
 641 {
 642         return pimpl_->lex();
 643 }
 644
 645
 646 int Lexer::getInteger() const
 647 {
 648         lastReadOk_ = pimpl_->status == LEX_DATA || pimpl_->status == LEX_TOKEN;
 649         if (!lastReadOk_) {
 650                 pimpl_->printError("integer token missing");
 651                 return -1;
 652         }
 653
 654         if (isStrInt(pimpl_->getString()))
 655                 return convert<int>(pimpl_->getString());
 656
 657         lastReadOk_ = false;
 658         pimpl_->printError("Bad integer `$$Token'");
 659         return -1;
 660 }
 661
 662
 663 double Lexer::getFloat() const
 664 {
 665         // replace comma with dot in case the file was written with
 666         // the wrong locale (should be rare, but is easy enough to
 667         // avoid).
 668         lastReadOk_ = pimpl_->status == LEX_DATA || pimpl_->status == LEX_TOKEN;
 669         if (!lastReadOk_) {
 670                 pimpl_->printError("float token missing");
 671                 return -1;
 672         }
 673
 674         string const str = subst(pimpl_->getString(), ",", ".");
 675         if (isStrDbl(str))
 676                 return convert<double>(str);
 677
 678         lastReadOk_ = false;
 679         pimpl_->printError("Bad float `$$Token'");
 680         return -1;
 681 }
 682
 683
 684 string const Lexer::getString() const
 685 {
 686         lastReadOk_ = pimpl_->status == LEX_DATA || pimpl_->status == LEX_TOKEN;
 687
 688         if (lastReadOk_)
 689         return pimpl_->getString();
 690
 691         return string();
 692 }
 693
 694
 695 docstring const Lexer::getDocString() const
 696 {
 697         lastReadOk_ = pimpl_->status == LEX_DATA || pimpl_->status == LEX_TOKEN;
 698
 699         if (lastReadOk_)
 700                 return pimpl_->getDocString();
 701
 702         return docstring();
 703 }
 704
 705
 706 // I would prefer to give a tag number instead of an explicit token
 707 // here, but it is not possible because Buffer::readDocument uses
 708 // explicit tokens (JMarc)
 709 string const Lexer::getLongString(string const & endtoken)
 710 {
 711         string str;
 712         string prefix;
 713         bool firstline = true;
 714
 715         while (pimpl_->is) { //< eatLine only reads from is, not from pushTok
 716                 if (!eatLine())
 717                         // blank line in the file being read
 718                         continue;
 719
 720                 string const token = trim(getString(), " \t");
 721
 722                 LYXERR(Debug::PARSER, "LongString: `" << getString() << '\'');
 723
 724                 // We do a case independent comparison, like searchKeyword does.
 725                 if (compare_ascii_no_case(token, endtoken) == 0)
 726                         break;
 727
 728                 string tmpstr = getString();
 729                 if (firstline) {
 730                         size_t i = tmpstr.find_first_not_of(' ');
 731                         if (i != string::npos)
 732                                 prefix = tmpstr.substr(0, i);
 733                         firstline = false;
 734                         LYXERR(Debug::PARSER, "Prefix = `" << prefix << "\'");
 735                 }
 736
 737                 // further lines in long strings may have the same
 738                 // whitespace prefix as the first line. Remove it.
 739                 if (prefix.length() && prefixIs(tmpstr, prefix))
 740                         tmpstr.erase(0, prefix.length() - 1);
 741
 742                 str += ltrim(tmpstr, "\t") + '\n';
 743         }
 744
 745         if (!pimpl_->is)
 746                 printError("Long string not ended by `" + endtoken + '\'');
 747
 748         return str;
 749 }
 750
 751
 752 bool Lexer::getBool() const
 753 {
 754         string const s = pimpl_->getString();
 755         if (s == "false" || s == "0") {
 756                 lastReadOk_ = true;
 757                 return false;
 758         }
 759         if (s == "true" || s == "1") {
 760                 lastReadOk_ = true;
 761                 return true;
 762         }
 763         pimpl_->printError("Bad boolean `$$Token'. "
 764                                  "Use \"false\" or \"true\"");
 765         lastReadOk_ = false;
 766         return false;
 767 }
 768
 769
 770 bool Lexer::eatLine()
 771 {
 772         return pimpl_->eatLine();
 773 }
 774
 775
 776 bool Lexer::next(bool esc)
 777 {
 778         return pimpl_->next(esc);
 779 }
 780
 781
 782 bool Lexer::nextToken()
 783 {
 784         return pimpl_->nextToken();
 785 }
 786
 787
 788 void Lexer::pushToken(string const & pt)
 789 {
 790         pimpl_->pushToken(pt);
 791 }
 792
 793
 794 Lexer::operator void const *() const
 795 {
 796         // This behaviour is NOT the same as the streams which would
 797         // use fail() here. However, our implementation of getString() et al.
 798         // can cause the eof() and fail() bits to be set, even though we
 799         // haven't tried to read 'em.
 800         return lastReadOk_? this : 0;
 801 }
 802
 803
 804 bool Lexer::operator!() const
 805 {
 806         return !lastReadOk_;
 807 }
 808
 809
 810 Lexer & Lexer::operator>>(string & s)
 811 {
 812         if (isOK()) {
 813                 next();
 814                 s = getString();
 815         } else {
 816                 lastReadOk_ = false;
 817         }
 818         return *this;
 819 }
 820
 821
 822 Lexer & Lexer::operator>>(docstring & s)
 823 {
 824         if (isOK()) {
 825                 next();
 826                 s = getDocString();
 827         } else {
 828                 lastReadOk_ = false;
 829         }
 830         return *this;
 831 }
 832
 833
 834 Lexer & Lexer::operator>>(double & s)
 835 {
 836         if (isOK()) {
 837                 next();
 838                 s = getFloat();
 839         } else {
 840                 lastReadOk_ = false;
 841         }
 842         return *this;
 843 }
 844
 845
 846 Lexer & Lexer::operator>>(int & s)
 847 {
 848         if (isOK()) {
 849                 next();
 850                 s = getInteger();
 851         } else {
 852                 lastReadOk_ = false;
 853         }
 854         return *this;
 855 }
 856
 857
 858 Lexer & Lexer::operator>>(unsigned int & s)
 859 {
 860         if (isOK()) {
 861                 next();
 862                 s = getInteger();
 863         } else {
 864                 lastReadOk_ = false;
 865         }
 866         return *this;
 867 }
 868
 869
 870 Lexer & Lexer::operator>>(bool & s)
 871 {
 872         if (isOK()) {
 873                 next();
 874                 s = getBool();
 875         } else {
 876                 lastReadOk_ = false;
 877         }
 878         return *this;
 879 }
 880
 881
 882 Lexer & Lexer::operator>>(char & c)
 883 {
 884         string s;
 885         operator>>(s);
 886         if (!s.empty())
 887                 c = s[0];
 888         return *this;
 889 }
 890
 891
 892 // quotes a string, e.g. for use in preferences files or as an argument
 893 // of the "log" dialog
 894 string Lexer::quoteString(string const & arg)
 895 {
 896         string res;
 897         res += '"';
 898         res += subst(subst(arg, "\\", "\\\\"), "\"", "\\\"");
 899         res += '"';
 900         return res;
 901 }
 902
 903
 904 Lexer & Lexer::operator>>(char const * required)
 905 {
 906         string token;
 907         *this >> token;
 908         if (token != required) {
 909                 LYXERR0("Missing '" << required << "'-tag in " << pimpl_->context
 910                         << ". Got " << token << " instead. Line: " << lineNumber());
 911                 pushToken(token);
 912         }
 913         return *this;
 914 }
 915
 916
 917 bool Lexer::checkFor(char const * required)
 918 {
 919         string token;
 920         *this >> token;
 921         if (token == required)
 922                 return true;
 923         pushToken(token);
 924         return false;
 925 }
 926
 927
 928 void Lexer::setContext(std::string const & str)
 929 {
 930         pimpl_->context = str;
 931 }
 932
 933
 934 } // namespace lyx