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#include <bu/parser.h>
#include <bu/lexer.h>
#include <bu/file.h>
#include <bu/sio.h>
#include <bu/queuebuf.h>
#include <stdlib.h>
using namespace Bu;
enum Tok
{
tokNumber,
tokPlus,
tokMinus,
tokDivide,
tokMultiply,
tokOpenParen,
tokCloseParen,
tokCompute,
tokEndOfInput=-1
};
Bu::Formatter &operator<<( Bu::Formatter &f, Tok e )
{
switch( e )
{
case tokNumber: return f << "tokNumber";
case tokPlus: return f << "tokPlus";
case tokMinus: return f << "tokMinus";
case tokDivide: return f << "tokDivide";
case tokMultiply: return f << "tokMultiply";
case tokOpenParen: return f << "tokOpenParen";
case tokCloseParen: return f << "tokCloseParen";
case tokCompute: return f << "tokCompute";
case tokEndOfInput: return f << "tokEndOfInput";
}
return f << "***error***";
}
class MathLexer : public Lexer
{
public:
MathLexer( Bu::Stream &rSrc ) :
rSrc( rSrc )
{
}
virtual ~MathLexer()
{
}
enum TokenTypes
{
tokStuff
};
virtual Token *nextToken()
{
for(;;)
{
if( qbIn.getSize() == 0 )
{
char buf[4096];
qbIn.write( buf, rSrc.read( buf, 4096 ) );
if( rSrc.isEos() && qbIn.getSize() == 0 )
return new Token( tokEndOfInput );
}
char b;
qbIn.peek( &b, 1 );
switch( b )
{
case '+':
qbIn.seek( 1 );
return new Token( tokPlus );
case '-':
qbIn.seek( 1 );
return new Token( tokMinus );
case '/':
qbIn.seek( 1 );
return new Token( tokDivide );
case '*':
qbIn.seek( 1 );
return new Token( tokMultiply );
case ' ':
case '\t':
case '\n':
qbIn.seek( 1 );
break;
case '=':
qbIn.seek( 1 );
return new Token( tokCompute );
case '(':
qbIn.seek( 1 );
return new Token( tokOpenParen );
case ')':
qbIn.seek( 1 );
return new Token( tokCloseParen );
case '.':
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
{
Bu::FString sTmp;
sTmp += b;
qbIn.seek( 1 );
for(;;)
{
qbIn.peek( &b, 1 );
if( b != '.' && (b < '0' || b > '9') )
{
sio << "!! Convert '" << sTmp << "' to "
<< strtod( sTmp.getStr(), NULL ) << sio.nl;
return new Token(
tokNumber, strtod( sTmp.getStr(), NULL )
);
}
qbIn.seek( 1 );
sTmp += b;
}
}
break;
default:
throw Bu::ExceptionBase("Unexpected character '%c'.", b );
}
}
}
private:
Bu::Stream &rSrc;
QueueBuf qbIn;
};
int main( int argc, char *argv[] )
{
File fIn( argv[1], File::Read );
Parser p;
p.pushLexer( new MathLexer( fIn ) );
p.parse();
return 0;
}
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