]> git.lyx.org Git - lyx.git/blobdiff - src/Lexer.cpp
Rename a variable
[lyx.git] / src / Lexer.cpp
index 4db980859f9d70b7277e2f79c172670d9a936d5e..098faa9737282c3fc40458ec67665b26b8b881ef 100644 (file)
@@ -4,7 +4,7 @@
  * Licence details can be found in the file COPYING.
  *
  * \author Alejandro Aguilar Sierra
- * \author Lars Gullik Bjønnes
+ * \author Lars Gullik Bjønnes
  * \author Jean-Marc Lasgouttes
  * \author John Levon
  *
 #include <config.h>
 
 #include "Lexer.h"
-
-#include "debug.h"
+#include "Format.h"
 
 #include "support/convert.h"
+#include "support/debug.h"
+#include "support/FileName.h"
 #include "support/filetools.h"
 #include "support/gzstream.h"
+#include "support/lassert.h"
 #include "support/lstrings.h"
 #include "support/lyxalgo.h"
 #include "support/types.h"
-#include "support/unicode.h"
-
-#include <boost/utility.hpp>
 
 #include <functional>
 #include <istream>
 #include <stack>
-#include <sstream>
 #include <vector>
 
+using namespace std;
+using namespace lyx::support;
 
 namespace lyx {
 
-using support::compare_ascii_no_case;
-using support::FileName;
-using support::getFormatFromContents;
-using support::isStrDbl;
-using support::isStrInt;
-using support::ltrim;
-using support::makeDisplayPath;
-using support::prefixIs;
-using support::split;
-using support::subst;
-using support::trim;
-
-using std::endl;
-using std::getline;
-using std::lower_bound;
-using std::sort;
-using std::string;
-using std::ios;
-using std::istream;
-using std::ostream;
-
-
 //////////////////////////////////////////////////////////////////////
 //
 // Lexer::Pimpl
@@ -66,32 +44,32 @@ using std::ostream;
 
 
 ///
-class Lexer::Pimpl : boost::noncopyable {
+class Lexer::Pimpl {
 public:
        ///
-       Pimpl(keyword_item * tab, int num);
+       Pimpl(LexerKeyword * tab, int num);
        ///
-       std::string const getString() const;
+       string const getString() const;
        ///
        docstring const getDocString() const;
        ///
-       void printError(std::string const & message) const;
+       void printError(string const & message) const;
        ///
-       void printTable(std::ostream & os);
+       void printTable(ostream & os);
        ///
-       void pushTable(keyword_item * tab, int num);
+       void pushTable(LexerKeyword * tab, int num);
        ///
        void popTable();
        ///
-       bool setFile(support::FileName const & filename);
+       bool setFile(FileName const & filename);
        ///
-       void setStream(std::istream & i);
+       void setStream(istream & i);
        ///
        void setCommentChar(char c);
        ///
        bool next(bool esc = false);
        ///
-       int search_kw(char const * const tag) const;
+       int searchKeyword(char const * const tag) const;
        ///
        int lex();
        ///
@@ -101,61 +79,67 @@ public:
        /// test if there is a pushed token or the stream is ok
        bool inputAvailable();
        ///
-       void pushToken(std::string const &);
+       void pushToken(string const &);
        /// fb_ is only used to open files, the stream is accessed through is.
-       std::filebuf fb_;
+       filebuf fb_;
 
        /// gz_ is only used to open files, the stream is accessed through is.
        gz::gzstreambuf gz_;
 
        /// the stream that we use.
-       std::istream is;
+       istream is;
        ///
-       std::string name;
+       string name;
        ///
-       keyword_item * table;
+       LexerKeyword * table;
        ///
        int no_items;
        ///
-       std::string buff;
+       string buff;
        ///
        int status;
        ///
        int lineno;
        ///
-       std::string pushTok;
+       string pushTok;
        ///
        char commentChar;
+       /// used for error messages
+       string context;
 private:
+       /// non-copyable
+       Pimpl(Pimpl const &);
+       void operator=(Pimpl const &);
+
        ///
        void verifyTable();
        ///
-       class pushed_table {
+       class PushedTable {
        public:
                ///
-               pushed_table()
+               PushedTable()
                        : table_elem(0), table_siz(0) {}
                ///
-               pushed_table(keyword_item * ki, int siz)
+               PushedTable(LexerKeyword * ki, int siz)
                        : table_elem(ki), table_siz(siz) {}
                ///
-               keyword_item * table_elem;
+               LexerKeyword * table_elem;
                ///
                int table_siz;
        };
        ///
-       std::stack<pushed_table> pushed;
+       stack<PushedTable> pushed;
 };
 
 
 
 namespace {
 
-class compare_tags
-       : public std::binary_function<keyword_item, keyword_item, bool> {
+class CompareTags
+       : public binary_function<LexerKeyword, LexerKeyword, bool> {
 public:
        // used by lower_bound, sort and sorted
-       bool operator()(keyword_item const & a, keyword_item const & b) const
+       bool operator()(LexerKeyword const & a, LexerKeyword const & b) const
        {
                // we use the ascii version, because in turkish, 'i'
                // is not the lowercase version of 'I', and thus
@@ -164,10 +148,10 @@ public:
        }
 };
 
-} // end of anon namespace
+} // namespace
 
 
-Lexer::Pimpl::Pimpl(keyword_item * tab, int num)
+Lexer::Pimpl::Pimpl(LexerKeyword * tab, int num)
        : is(&fb_), table(tab), no_items(num),
          status(0), lineno(0), commentChar('#')
 {
@@ -191,7 +175,9 @@ void Lexer::Pimpl::printError(string const & message) const
 {
        string const tmpmsg = subst(message, "$$Token", getString());
        lyxerr << "LyX: " << tmpmsg << " [around line " << lineno
-               << " of file " << to_utf8(makeDisplayPath(name)) << ']' << endl;
+               << " of file " << to_utf8(makeDisplayPath(name))
+               << " current token: '" << getString() << "'"
+               << " context: '" << context << "']" << endl;
 }
 
 
@@ -210,23 +196,23 @@ void Lexer::Pimpl::verifyTable()
 {
        // Check if the table is sorted and if not, sort it.
        if (table
-           && !lyx::sorted(table, table + no_items, compare_tags())) {
+           && !lyx::sorted(table, table + no_items, CompareTags())) {
                lyxerr << "The table passed to Lexer is not sorted!\n"
                       << "Tell the developers to fix it!" << endl;
                // We sort it anyway to avoid problems.
                lyxerr << "\nUnsorted:" << endl;
                printTable(lyxerr);
 
-               sort(table, table + no_items, compare_tags());
+               sort(table, table + no_items, CompareTags());
                lyxerr << "\nSorted:" << endl;
                printTable(lyxerr);
        }
 }
 
 
-void Lexer::Pimpl::pushTable(keyword_item * tab, int num)
+void Lexer::Pimpl::pushTable(LexerKeyword * tab, int num)
 {
-       pushed_table tmppu(table, no_items);
+       PushedTable tmppu(table, no_items);
        pushed.push(tmppu);
 
        table = tab;
@@ -243,7 +229,7 @@ void Lexer::Pimpl::popTable()
                return;
        }
 
-       pushed_table tmp = pushed.top();
+       PushedTable tmp = pushed.top();
        pushed.pop();
        table = tmp.table_elem;
        no_items = tmp.table_siz;
@@ -253,45 +239,57 @@ void Lexer::Pimpl::popTable()
 bool Lexer::Pimpl::setFile(FileName const & filename)
 {
        // Check the format of the file.
-       string const format = getFormatFromContents(filename);
-
-       if (format == "gzip" || format == "zip" || format == "compress") {
-               LYXERR(Debug::LYXLEX) << "lyxlex: compressed" << endl;
+       if (theFormats().isZippedFile(filename)) {
+               LYXERR(Debug::LYXLEX, "lyxlex: compressed");
                // The check only outputs a debug message, because it triggers
                // a bug in compaq cxx 6.2, where is_open() returns 'true' for
                // a fresh new filebuf.  (JMarc)
                if (gz_.is_open() || istream::off_type(is.tellg()) > -1)
-                       lyxerr[Debug::LYXLEX] << "Error in LyXLex::setFile: "
-                               "file or stream already set." << endl;
+                       LYXERR(Debug::LYXLEX, "Error in LyXLex::setFile: "
+                               "file or stream already set.");
                gz_.open(filename.toFilesystemEncoding().c_str(), ios::in);
                is.rdbuf(&gz_);
-               name = filename.absFilename();
+               name = filename.absFileName();
                lineno = 0;
-               return gz_.is_open() && is.good();
+               if (!gz_.is_open() || !is.good())
+                       return false;
        } else {
-               LYXERR(Debug::LYXLEX) << "lyxlex: UNcompressed" << endl;
+               LYXERR(Debug::LYXLEX, "lyxlex: UNcompressed");
 
                // The check only outputs a debug message, because it triggers
                // a bug in compaq cxx 6.2, where is_open() returns 'true' for
                // a fresh new filebuf.  (JMarc)
                if (fb_.is_open() || istream::off_type(is.tellg()) > 0) {
-                       LYXERR(Debug::LYXLEX) << "Error in Lexer::setFile: "
-                               "file or stream already set." << endl;
+                       LYXERR(Debug::LYXLEX, "Error in Lexer::setFile: "
+                               "file or stream already set.");
                }
-               fb_.open(filename.toFilesystemEncoding().c_str(), ios::in);
+               fb_.open(filename.toSafeFilesystemEncoding().c_str(), ios::in);
                is.rdbuf(&fb_);
-               name = filename.absFilename();
+               name = filename.absFileName();
                lineno = 0;
-               return fb_.is_open() && is.good();
+               if (!fb_.is_open() || !is.good())
+                       return false;
+       }
+
+       // Skip byte order mark.
+       if (is.peek() == 0xef) {
+               is.get();
+               if (is.peek() == 0xbb) {
+                       is.get();
+                       LASSERT(is.get() == 0xbf, /**/);
+               } else
+                       is.unget();
        }
+
+       return true;
 }
 
 
 void Lexer::Pimpl::setStream(istream & i)
 {
        if (fb_.is_open() || istream::off_type(is.tellg()) > 0) {
-               LYXERR(Debug::LYXLEX)  << "Error in Lexer::setStream: "
-                       "file or stream already set." << endl;
+               LYXERR(Debug::LYXLEX, "Error in Lexer::setStream: "
+                       "file or stream already set.");
        }
        is.rdbuf(i.rdbuf());
        lineno = 0;
@@ -320,127 +318,37 @@ bool Lexer::Pimpl::next(bool esc /* = false */)
                status = LEX_TOKEN;
                return true;
        }
-       if (!esc) {
-               unsigned char c = 0; // getc() returns an int
-               char cc = 0;
-               status = 0;
-               while (is && !status) {
-                       is.get(cc);
-                       c = cc;
-                       if (c == commentChar) {
-                               // Read rest of line (fast :-)
-#if 1
-                               // That is not fast... (Lgb)
-                               string dummy;
-                               getline(is, dummy);
-
-                               LYXERR(Debug::LYXLEX) << "Comment read: `" << c
-                                                     << dummy << '\'' << endl;
-#else
-                               // unfortunately ignore is buggy (Lgb)
-                               is.ignore(100, '\n');
-#endif
-                               ++lineno;
-                               continue;
-                       }
-
-                       if (c == '\"') {
-                               buff.clear();
-
-                               do {
-                                       is.get(cc);
-                                       c = cc;
-                                       if (c != '\r')
-                                               buff.push_back(c);
-                               } while (c != '\"' && c != '\n' && is);
-
-                               if (c != '\"') {
-                                       printError("Missing quote");
-                                       if (c == '\n')
-                                               ++lineno;
-                               }
-
-                               buff.resize(buff.size()-1);
-                               status = LEX_DATA;
-                               break;
-                       }
-
-                       if (c == ',')
-                               continue;              /* Skip ','s */
-
-                               // using relational operators with chars other
-                               // than == and != is not safe. And if it is done
-                               // the type _have_ to be unsigned. It usually a
-                               // lot better to use the functions from cctype
-                       if (c > ' ' && is)  {
-                               buff.clear();
-
-                               do {
-                                       buff.push_back(c);
-                                       is.get(cc);
-                                       c = cc;
-                               } while (c > ' ' && c != ',' && is);
-
-                               status = LEX_TOKEN;
-                       }
-
-                       if (c == '\r' && is) {
-                               // The Windows support has lead to the
-                               // possibility of "\r\n" at the end of
-                               // a line.  This will stop LyX choking
-                               // when it expected to find a '\n'
-                               is.get(cc);
-                               c = cc;
-                       }
-
-                       if (c == '\n')
-                               ++lineno;
-
-               }
-               if (status)
-                       return true;
 
-               status = is.eof() ? LEX_FEOF: LEX_UNDEF;
-               buff.clear();
-               return false;
-       } else {
-               unsigned char c = 0; // getc() returns an int
-               char cc = 0;
 
-               status = 0;
-               while (is && !status) {
-                       is.get(cc);
-                       c = cc;
-
-                       // skip ','s
-                       if (c == ',')
-                               continue;
+       char cc = 0;
+       status = 0;
+       while (is && !status) {
+               is.get(cc);
+               unsigned char c = cc;
 
-                       if (c == commentChar) {
-                               // Read rest of line (fast :-)
+               if (c == commentChar) {
+                       // Read rest of line (fast :-)
 #if 1
-                               // That is still not fast... (Lgb)
-                               string dummy;
-                               getline(is, dummy);
+                       // That is not fast... (Lgb)
+                       string dummy;
+                       getline(is, dummy);
 
-                               LYXERR(Debug::LYXLEX) << "Comment read: `" << c
-                                                     << dummy << '\'' << endl;
+                       LYXERR(Debug::LYXLEX, "Comment read: `" << c << dummy << '\'');
 #else
-                               // but ignore is also still buggy (Lgb)
-                               // This is fast (Lgb)
-                               is.ignore(100, '\n');
+                       // unfortunately ignore is buggy (Lgb)
+                       is.ignore(100, '\n');
 #endif
-                               ++lineno;
-                               continue;
-                       }
+                       ++lineno;
+                       continue;
+               }
+
+               if (c == '\"') {
+                       buff.clear();
 
-                       // string
-                       if (c == '\"') {
-                               buff.clear();
+                       if (esc) {
 
-                               bool escaped = false;
                                do {
-                                       escaped = false;
+                                       bool escaped = false;
                                        is.get(cc);
                                        c = cc;
                                        if (c == '\r') continue;
@@ -459,55 +367,80 @@ bool Lexer::Pimpl::next(bool esc /* = false */)
                                                break;
                                } while (c != '\n' && is);
 
-                               if (c != '\"') {
-                                       printError("Missing quote");
-                                       if (c == '\n')
-                                               ++lineno;
-                               }
+                       } else {
+
+                               do {
+                                       is.get(cc);
+                                       c = cc;
+                                       if (c != '\r')
+                                               buff.push_back(c);
+                               } while (c != '\"' && c != '\n' && is);
 
-                               buff.resize(buff.size() -1);
-                               status = LEX_DATA;
-                               break;
                        }
 
-                       if (c > ' ' && is) {
-                               buff.clear();
+                       if (c != '\"') {
+                               printError("Missing quote");
+                               if (c == '\n')
+                                       ++lineno;
+                       }
 
-                               do {
-                                       if (c == '\\') {
-                                               // escape the next char
-                                               is.get(cc);
-                                               c = cc;
-                                               //escaped = true;
-                                       }
-                                       buff.push_back(c);
+                       buff.resize(buff.size() - 1);
+                       status = LEX_DATA;
+                       break;
+               }
+
+               if (c == ',')
+                       continue;              /* Skip ','s */
+
+               // using relational operators with chars other
+               // than == and != is not safe. And if it is done
+               // the type _have_ to be unsigned. It usually a
+               // lot better to use the functions from cctype
+               if (c > ' ' && is)  {
+                       buff.clear();
+
+                       do {
+                               if (esc && c == '\\') {
+                                       // escape the next char
                                        is.get(cc);
                                        c = cc;
-                               } while (c > ' ' && c != ',' && is);
+                                       //escaped = true;
+                               }
+                               buff.push_back(c);
+                               is.get(cc);
+                               c = cc;
+                       } while (c > ' ' && c != ',' && is);
+                       status = LEX_TOKEN;
+               }
 
-                               status = LEX_TOKEN;
-                       }
-                       // new line
-                       if (c == '\n')
-                               ++lineno;
+               if (c == '\r' && is) {
+                       // The Windows support has lead to the
+                       // possibility of "\r\n" at the end of
+                       // a line.  This will stop LyX choking
+                       // when it expected to find a '\n'
+                       is.get(cc);
+                       c = cc;
                }
 
-               if (status)
-                       return true;
+               if (c == '\n')
+                       ++lineno;
 
-               status = is.eof() ? LEX_FEOF : LEX_UNDEF;
-               buff.clear();
-               return false;
        }
+       if (status)
+               return true;
+
+       status = is.eof() ? LEX_FEOF: LEX_UNDEF;
+       buff.clear();
+       return false;
 }
 
 
-int Lexer::Pimpl::search_kw(char const * const tag) const
+int Lexer::Pimpl::searchKeyword(char const * const tag) const
 {
-       keyword_item search_tag = { tag, 0 };
-       keyword_item * res =
+       LexerKeyword search_tag = { tag, 0 };
+       LexerKeyword * res =
                lower_bound(table, table + no_items,
-                           search_tag, compare_tags());
+                           search_tag, CompareTags());
        // use the compare_ascii_no_case instead of compare_no_case,
        // because in turkish, 'i' is not the lowercase version of 'I',
        // and thus turkish locale breaks parsing of tags.
@@ -522,7 +455,7 @@ int Lexer::Pimpl::lex()
 {
        //NOTE: possible bug.
        if (next() && status == LEX_TOKEN)
-               return search_kw(getString().c_str());
+               return searchKeyword(getString().c_str());
        return status;
 }
 
@@ -536,9 +469,8 @@ bool Lexer::Pimpl::eatLine()
        while (is && c != '\n') {
                is.get(cc);
                c = cc;
-               //LYXERR(Debug::LYXLEX) << "Lexer::EatLine read char: `"
-               //                    << c << '\'' << endl;
-               if (c != '\r')
+               //LYXERR(Debug::LYXLEX, "Lexer::EatLine read char: `" << c << '\'');
+               if (c != '\r' && is)
                        buff.push_back(c);
        }
 
@@ -579,7 +511,7 @@ bool Lexer::Pimpl::nextToken()
                char cc = 0;
                is.get(cc);
                c = cc;
-               if (c >= ' ' && is) {
+               if ((c >= ' ' || c == '\t') && is) {
                        buff.clear();
 
                        if (c == '\\') { // first char == '\\'
@@ -593,10 +525,11 @@ bool Lexer::Pimpl::nextToken()
                                        buff.push_back(c);
                                        is.get(cc);
                                        c = cc;
-                               } while (c >= ' ' && c != '\\' && is);
+                               } while ((c >= ' ' || c == '\t') && c != '\\' && is);
                        }
 
-                       if (c == '\\') is.putback(c); // put it back
+                       if (c == '\\')
+                               is.putback(c); // put it back
                        status = LEX_TOKEN;
                }
 
@@ -633,11 +566,17 @@ void Lexer::Pimpl::pushToken(string const & pt)
 //
 //////////////////////////////////////////////////////////////////////
 
-Lexer::Lexer(keyword_item * tab, int num)
-       : pimpl_(new Pimpl(tab, num))
+Lexer::Lexer()
+       : pimpl_(new Pimpl(0, 0)), lastReadOk_(false)
 {}
 
 
+void Lexer::init(LexerKeyword * tab, int num)
+{
+        pimpl_ = new Pimpl(tab, num);
+}
+
+
 Lexer::~Lexer()
 {
        delete pimpl_;
@@ -650,13 +589,13 @@ bool Lexer::isOK() const
 }
 
 
-void Lexer::setLineNo(int l)
+void Lexer::setLineNumber(int l)
 {
        pimpl_->lineno = l;
 }
 
 
-int Lexer::getLineNo() const
+int Lexer::lineNumber() const
 {
        return pimpl_->lineno;
 }
@@ -668,7 +607,7 @@ istream & Lexer::getStream()
 }
 
 
-void Lexer::pushTable(keyword_item * tab, int num)
+void Lexer::pushTable(LexerKeyword * tab, int num)
 {
        pimpl_->pushTable(tab, num);
 }
@@ -692,7 +631,7 @@ void Lexer::printError(string const & message) const
 }
 
 
-bool Lexer::setFile(support::FileName const & filename)
+bool Lexer::setFile(FileName const & filename)
 {
        return pimpl_->setFile(filename);
 }
@@ -709,6 +648,7 @@ void Lexer::setCommentChar(char c)
        pimpl_->setCommentChar(c);
 }
 
+
 int Lexer::lex()
 {
        return pimpl_->lex();
@@ -753,23 +693,23 @@ double Lexer::getFloat() const
 }
 
 
-string const Lexer::getString() const
+string const Lexer::getString(bool trim) const
 {
        lastReadOk_ = pimpl_->status == LEX_DATA || pimpl_->status == LEX_TOKEN;
 
        if (lastReadOk_)
-       return pimpl_->getString();
+               return trim ? support::trim(pimpl_->getString(), "\t ") : pimpl_->getString();
 
        return string();
 }
 
 
-docstring const Lexer::getDocString() const
+docstring const Lexer::getDocString(bool trim) const
 {
        lastReadOk_ = pimpl_->status == LEX_DATA || pimpl_->status == LEX_TOKEN;
 
        if (lastReadOk_)
-               return pimpl_->getDocString();
+               return trim ? support::trim(pimpl_->getDocString(), "\t ") : pimpl_->getDocString();
 
        return docstring();
 }
@@ -778,47 +718,43 @@ docstring const Lexer::getDocString() const
 // I would prefer to give a tag number instead of an explicit token
 // here, but it is not possible because Buffer::readDocument uses
 // explicit tokens (JMarc)
-string const Lexer::getLongString(string const & endtoken)
+docstring Lexer::getLongString(docstring const & endtoken)
 {
-       string str, prefix;
+       docstring str;
+       docstring prefix;
        bool firstline = true;
 
        while (pimpl_->is) { //< eatLine only reads from is, not from pushTok
                if (!eatLine())
                        // blank line in the file being read
                        continue;
+               docstring tmpstr = getDocString();
+               docstring const token = trim(tmpstr, " \t");
 
-               string const token = trim(getString(), " \t");
-
-               LYXERR(Debug::PARSER) << "LongString: `"
-                                     << getString() << '\'' << endl;
+               LYXERR(Debug::PARSER, "LongString: `" << tmpstr << '\'');
 
-               // We do a case independent comparison, like search_kw does.
-               if (compare_ascii_no_case(token, endtoken) == 0)
+               // We do a case independent comparison, like searchKeyword does.
+               if (compare_no_case(token, endtoken) == 0)
                        break;
 
-               string tmpstr = getString();
                if (firstline) {
-                       string::size_type i(tmpstr.find_first_not_of(' '));
+                       size_t i = tmpstr.find_first_not_of(from_ascii(" \t"));
                        if (i != string::npos)
                                prefix = tmpstr.substr(0, i);
                        firstline = false;
-                       LYXERR(Debug::PARSER)
-                               << "Prefix = `" << prefix << "\'" << endl;
+                       LYXERR(Debug::PARSER, "Prefix = `" << prefix << "\'");
                }
 
                // further lines in long strings may have the same
                // whitespace prefix as the first line. Remove it.
-               if (prefix.length() && prefixIs(tmpstr, prefix)) {
-                       tmpstr.erase(0, prefix.length() - 1);
-               }
+               if (!prefix.empty() && prefixIs(tmpstr, prefix))
+                       tmpstr.erase(0, prefix.length());
 
-               str += ltrim(tmpstr, "\t") + '\n';
+               str += tmpstr + '\n';
        }
 
-       if (!pimpl_->is) {
-               printError("Long string not ended by `" + endtoken + '\'');
-       }
+       if (!pimpl_->is)
+               printError("Long string not ended by `" + to_utf8(endtoken) + '\'');
 
        return str;
 }
@@ -826,15 +762,18 @@ string const Lexer::getLongString(string const & endtoken)
 
 bool Lexer::getBool() const
 {
-       if (pimpl_->getString() == "true") {
+       string const s = pimpl_->getString();
+       if (s == "false" || s == "0") {
+               lastReadOk_ = true;
+               return false;
+       }
+       if (s == "true" || s == "1") {
                lastReadOk_ = true;
                return true;
-       } else if (pimpl_->getString() != "false") {
-               pimpl_->printError("Bad boolean `$$Token'. "
-                                  "Use \"false\" or \"true\"");
-               lastReadOk_ = false;
        }
-       lastReadOk_ = true;
+       pimpl_->printError("Bad boolean `$$Token'. "
+                                "Use \"false\" or \"true\"");
+       lastReadOk_ = false;
        return false;
 }
 
@@ -865,7 +804,7 @@ void Lexer::pushToken(string const & pt)
 
 Lexer::operator void const *() const
 {
-       // This behaviour is NOT the same as the std::streams which would
+       // This behaviour is NOT the same as the streams which would
        // use fail() here. However, our implementation of getString() et al.
        // can cause the eof() and fail() bits to be set, even though we
        // haven't tried to read 'em.
@@ -879,7 +818,7 @@ bool Lexer::operator!() const
 }
 
 
-Lexer & Lexer::operator>>(std::string & s)
+Lexer & Lexer::operator>>(string & s)
 {
        if (isOK()) {
                next();
@@ -951,12 +890,67 @@ Lexer & Lexer::operator>>(bool & s)
 }
 
 
-/// quotes a string, e.g. for use in preferences files or as an argument of the "log" dialog
-string const Lexer::quoteString(string const & arg)
+Lexer & Lexer::operator>>(char & c)
+{
+       string s;
+       operator>>(s);
+       if (!s.empty())
+               c = s[0];
+       return *this;
+}
+
+
+// quotes a string, e.g. for use in preferences files or as an argument
+// of the "log" dialog
+string Lexer::quoteString(string const & arg)
+{
+       string res;
+       res += '"';
+       res += subst(subst(arg, "\\", "\\\\"), "\"", "\\\"");
+       res += '"';
+       return res;
+}
+
+
+// same for docstring
+docstring Lexer::quoteString(docstring const & arg)
+{
+       docstring res;
+       res += '"';
+       res += subst(subst(arg, from_ascii("\\"), from_ascii("\\\\")),
+                    from_ascii("\""), from_ascii("\\\""));
+       res += '"';
+       return res;
+}
+
+
+Lexer & Lexer::operator>>(char const * required)
+{
+       string token;
+       *this >> token;
+       if (token != required) {
+               LYXERR0("Missing '" << required << "'-tag in " << pimpl_->context
+                       << ". Got " << token << " instead. Line: " << lineNumber());
+               pushToken(token);
+       }
+       return *this;
+}
+
+
+bool Lexer::checkFor(char const * required)
+{
+       string token;
+       *this >> token;
+       if (token == required)
+               return true;
+       pushToken(token);
+       return false;
+}
+
+
+void Lexer::setContext(std::string const & str)
 {
-       std::ostringstream os;
-       os << '"' << subst(subst(arg, "\\", "\\\\"), "\"", "\\\"") << '"';
-       return os.str();
+       pimpl_->context = str;
 }