/* $Id: scanner.ll 44 2008-10-23 09:03:19Z tb $ -*- mode: c++ -*- */
/** \file scanner.ll Define the example Flex lexical scanner */
%{ /*** C/C++ Declarations ***/
#include <string>
#include "scanner.h"
/* import the parser's token type into a local typedef */
typedef example::Parser::token token;
typedef example::Parser::token_type token_type;
/* By default yylex returns int, we use token_type. Unfortunately yyterminate
* by default returns 0, which is not of token_type. */
#define yyterminate() return token::END
/* This disables inclusion of unistd.h, which is not available under Visual C++
* on Win32. The C++ scanner uses STL streams instead. */
#define YY_NO_UNISTD_H
%}
/*** Flex Declarations and Options ***/
/* enable c++ scanner class generation */
%option c++
/* change the name of the scanner class. results in "ExampleFlexLexer" */
%option prefix="Example"
/* the manual says "somewhat more optimized" */
%option batch
/* enable scanner to generate debug output. disable this for release
* versions. */
%option debug
/* no support for include files is planned */
%option yywrap nounput
/* enables the use of start condition stacks */
%option stack
/* The following paragraph suffices to track locations accurately. Each time
* yylex is invoked, the begin position is moved onto the end position. */
%{
#define YY_USER_ACTION yylloc->columns(yyleng);
%}
%% /*** Regular Expressions Part ***/
/* code to place at the beginning of yylex() */
%{
// reset location
yylloc->step();
%}
/*** BEGIN EXAMPLE - Change the example lexer rules below ***/
[0-9]+ {
yylval->integerVal = atoi(yytext);
return token::INTEGER;
}
[0-9]+"."[0-9]* {
yylval->doubleVal = atof(yytext);
return token::DOUBLE;
}
[A-Za-z][A-Za-z0-9_,.-]* {
yylval->stringVal = new std::string(yytext, yyleng);
return token::STRING;
}
/* gobble up white-spaces */
[ \t\r]+ {
yylloc->step();
}
/* gobble up end-of-lines */
\n {
yylloc->lines(yyleng); yylloc->step();
return token::EOL;
}
/* pass all other characters up to bison */
. {
return static_cast<token_type>(*yytext);
}
/*** END EXAMPLE - Change the example lexer rules above ***/
%% /*** Additional Code ***/
namespace example {
Scanner::Scanner(std::istream* in,
std::ostream* out)
: ExampleFlexLexer(in, out)
{
}
Scanner::~Scanner()
{
}
void Scanner::set_debug(bool b)
{
yy_flex_debug = b;
}
}
/* This implementation of ExampleFlexLexer::yylex() is required to fill the
* vtable of the class ExampleFlexLexer. We define the scanner's main yylex
* function via YY_DECL to reside in the Scanner class instead. */
#ifdef yylex
#undef yylex
#endif
int ExampleFlexLexer::yylex()
{
std::cerr << "in ExampleFlexLexer::yylex() !" << std::endl;
return 0;
}
/* When the scanner receives an end-of-file indication from YY_INPUT, it then
* checks the yywrap() function. If yywrap() returns false (zero), then it is
* assumed that the function has gone ahead and set up `yyin' to point to
* another input file, and scanning continues. If it returns true (non-zero),
* then the scanner terminates, returning 0 to its caller. */
int ExampleFlexLexer::yywrap()
{
return 1;
}
