lyx_mirror/src/Lexer.h
Jean-Marc Lasgouttes 0e2ef88b43 Fix uninitialized member in Lexer constructor
Fixes coverity issue 23501.
2015-03-05 12:24:47 +01:00

266 lines
6.6 KiB
C++

// -*- C++ -*-
/**
* \file Lexer.h
* This file is part of LyX, the document processor.
* Licence details can be found in the file COPYING.
*
* \author Alejandro Aguilar Sierra
* \author Lars Gullik Bjønnes
*
* Full author contact details are available in file CREDITS.
*/
// Generalized simple lexical analizer.
// It can be used for simple syntax parsers, like lyxrc,
// texclass and others to come.
#ifndef LEXER_H
#define LEXER_H
#include "support/strfwd.h"
#include <string>
namespace lyx {
namespace support { class FileName; }
class PushPopHelper;
/** A helper structure to describe a keyword for the Lexer.
Usually used bundled in C style arrays and passed to the
Lexer using a LexerKeywordTable object.
*/
struct LexerKeyword
{
/// the string to be recognized
char const * tag;
/// a corresponding numerical id
int code;
};
/** Generalized simple lexical analizer.
Use the method isOK() to check if there is still data available
for lexing. Use one of the the operators void* or ! to test if
the last reading operation was successful.
Example:
int readParam(LyxLex & lex)
{
int param = 1; // default value
if (lex.isOK()) { // the lexer has data to read
int p; // temporary variable
lex >> p;
if (lex)
param = p; // only use the input if reading was successful
}
return param;
}
@see LyXRC.cpp for an example of usage.
*/
class Lexer
{
public:
/// initialize Lexer with no special keywords.
Lexer();
/// initialize Lexer with a bunch of keywords
template<int N> Lexer(LexerKeyword (&table)[N])
: pimpl_(0), lastReadOk_(false) { init(table, N); }
///
~Lexer();
/// Lex basic codes
enum {
///
LEX_UNDEF = -1,
///
LEX_FEOF = -2,
///
LEX_DATA = -3,
///
LEX_TOKEN = -4
};
/// stream is open and end of stream is not reached
/// FIXME: test also if pushToken is not empty
/// FIXME: the method should be renamed to something like
/// dataAvailable(), in order to reflect the real behavior
bool isOK() const;
/// FIXME: The next two operators should be replaced by one method
/// called e.g. lastReadOk(), in order to reflect the real
/// behavior
/// last read operation was successful.
operator void const *() const;
/// last read operation was not successful
bool operator!() const;
/// return true if able to open file, else false
bool setFile(support::FileName const & filename);
///
void setStream(std::istream & is);
///
std::istream & getStream();
/// Danger! Don't use it unless you know what you are doing.
void setLineNumber(int l);
/// Change the character that begins a comment. Default is '#'
void setCommentChar(char c);
/// returns a lex code
int lex();
/// Read the next string, as delimited by double quotes or
/// whitespace. If esc is true, then we remember that some chars
/// might be escaped: \" at least.
bool next(bool esc = false);
/// Read next token. This one is almost the same as next(),
/// but it will consider " as a regular character and always
/// split a word if it contains a backslash.
bool nextToken();
/// Puts the rest of the line in the buffer, where it will
/// be available via getString() or getDocString().
bool eatLine();
/// Push a token, that next token got from lyxlex.
void pushToken(std::string const &);
/// return the current line number
int lineNumber() const;
///
int getInteger() const;
///
bool getBool() const;
///
double getFloat() const;
///
std::string const getString() const;
///
docstring const getDocString() const;
/** Get a long string, ended by the tag `endtag'.
This string can span several lines. The first line
serves as a template for how many spaces the lines
are indented. This much white space is skipped from
each following line. This mechanism does not work
perfectly if you use tabs.
*/
std::string const getLongString(std::string const & endtag);
/// Pushes a token list on a stack and replaces it with a new one.
template<int N> void pushTable(LexerKeyword (&table)[N])
{ pushTable(table, N); }
/** Pops a token list into void and replaces it with the one now
on top of the stack.
*/
void popTable();
/** Prints an error message with the corresponding line number
and file name. If message contains the substring `$$Token',
it is replaced with the value of GetString()
*/
void printError(std::string const & message) const;
/// Prints the current token table on the supplied ostream.
void printTable(std::ostream &);
/// Used to dispaly context information in case of errors.
void setContext(std::string const & functionName);
/// extract string
Lexer & operator>>(std::string &);
/// extract docstring
Lexer & operator>>(docstring &);
/// extract double
Lexer & operator>>(double &);
/// extract integer
Lexer & operator>>(int &);
/// extract unsigned integer
Lexer & operator>>(unsigned int &);
/// extract bool
Lexer & operator>>(bool &);
/// extract first char of the string
Lexer & operator>>(char &);
/// read and check a required token
Lexer & operator>>(char const * required);
/// check for an optional token and swallow it if present.
bool checkFor(char const * required);
/// Quotes a string so that reading it again with Lexer::next(true)
/// gets the original string
static std::string quoteString(std::string const &);
/// Quotes a docstring so that reading it again with Lexer::next(true)
/// gets the original string
static docstring quoteString(docstring const &);
private:
/// noncopyable
Lexer(Lexer const &);
void operator=(Lexer const &);
///
friend class PushPopHelper;
///
void init(LexerKeyword *, int);
void pushTable(LexerKeyword *, int);
///
class Pimpl;
///
Pimpl * pimpl_;
///
mutable bool lastReadOk_;
};
/// extract something constructable from a string, i.e. a LaTeX length
template <class T>
Lexer & operator>>(Lexer & lex, T & t)
{
if (lex.next())
t = T(lex.getString());
return lex;
}
/** Use to enable multiple exit points.
This is needed to ensure that the pop is done upon exit from methods
with more than one exit point or that can return as a response to
exceptions.
@author Lgb
*/
class PushPopHelper
{
public:
///
template<int N>
PushPopHelper(Lexer & l, LexerKeyword (&table)[N])
: lex(l)
{
lex.pushTable(table, N);
}
///
~PushPopHelper()
{
lex.popTable();
}
///
Lexer & lex;
};
/** Avoid wrong usage of PushPopHelper.
To avoid wrong usage:
PushPopHelper(...); // wrong
PushPopHelper pph(...); // right
*/
#define PushPopHelper(x, y, z) unnamed_PushPopHelper;
// Tip gotten from Bobby Schmidt's column in C/C++ Users Journal
} // namespace lyx
#endif