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/*
Author : Shakti Misra
All are welcome to use these files, distribute, modify and release. But This notice should be included.
This software is given as is, for use and modification.
*/
#include "Lexer.h"
/*
Parse the input characters and return the proper token for each. Get character one by one, and
*/
enmTokens Lex::getNextToken()
{
switch(getNextChar())
{
case '\0':
m_eCurToken = eTokenOver;break;//End of file reached
case '<':
m_eCurToken = eLeftAngleBracket;break;
case '=':
m_eCurToken = eEqualTo;break;
case '\\':
switch(getNextChar())
{
case '>':
m_eCurToken = eGreaterThan;break;
case '<':
if('>' == getNextChar())
{
m_eCurToken = eCompareGeneral;
}
else
{
m_fileReader.unreadChar( getCurrentChar() );
m_eCurToken = eLessThan;
}
break;
case '=':
m_eCurToken = eEquality;break;
default:
m_fileReader.unreadChar( getCurrentChar() );
m_eCurToken = eBackSlash;break;
}
break;
case '.':
m_eCurToken = eDspCurVal;break;//Display value
case '*':
m_eCurToken = eStarChar;break;
/*case '<':
m_eCurToken = eDecrHead;break;*/
case '+'://If we have + it can be either ++ or +*. So see where it falls
switch(getNextChar())
{
case '+':
m_eCurToken = eIncrContent;break;
case '*':
m_eCurToken = eAddWithNext;break;
default:
m_eCurToken = eUnknown;break;
}
break;
case '-'://If we have - it can be either -- or -*. So see where it falls
switch(getNextChar())
{
case '-':
m_eCurToken = eDecrContent;break;
case '*':
m_eCurToken = eSubNext;break;
default:
m_eCurToken = eUnknown;break;
}
break;
case '>'://If we have >, it can be >> if we have single > then its not avalid token
switch(getNextChar())
{
case '>':
m_eCurToken = eRdAndStrVal;break;
default:
m_fileReader.unreadChar(getCurrentChar());
m_eCurToken = eRightAngleBracket;break;
}
break;
case '!':
m_eCurToken = eExclaimationMark;break;
case '[':
m_eCurToken = eLeftSqrParen;break;
case ']':
m_eCurToken = eRightSqrParen;break;
case '(':
m_eCurToken = eLeftParen;break;
case ')':
m_eCurToken = eRightParen;break;
case 'I':
switch(getNextChar())
{
case 'F':
m_eCurToken = eIF;break;
default:
m_fileReader.unreadChar(getCurrentChar());
m_eCurToken = eUnknown;break;
}
break;
case 'F':
switch(getNextChar())
{
case 'I':
m_eCurToken = eFI;break;
default:
m_fileReader.unreadChar(getCurrentChar());
m_eCurToken = eUnknown;break;
}
break;
case 'D':
switch(getNextChar())
{
case 'O':
if('N' == getNextChar())
{
if('E' == getNextChar())
m_eCurToken = eDONE;
else
{//Back track block
m_fileReader.unreadChar('O');
m_fileReader.unreadChar('N');//If i come in this block i know its already N
m_fileReader.unreadChar(getCurrentChar());//Back trace
}
break;
}
else
{
m_fileReader.unreadChar(getCurrentChar());//Back trace
m_eCurToken = eDO;//We dont seperate tokens by first match
//We do them by first cum first serve basis
}
break;
default:
m_fileReader.unreadChar(getCurrentChar());//Back trace
m_eCurToken = eUnknown;break;
}
break;
case '#':
switch(getNextChar())
{
case 'B':
m_eCurToken = eBlock;break;
default:
m_fileReader.unreadChar(getCurrentChar());//Back trace
m_eCurToken = eUnknown;break;
}
break;
case ':':
m_eCurToken = eColon;
break;
case '/':
switch(getNextChar())
{
case '*':
while('/' != getNextChar());break;//TODO need to improve it.
}
break;
default:
if( isdigit( getCurrentChar() ) )
{
m_fileReader.unreadChar(getCurrentChar());
int val = m_fileReader.getNextNumber();
m_eCurToken = eIntNumber;
m_tokAttrib.setAttribVal(val);
}
else if( isalpha( getCurrentChar() ) )
{
char val = getCurrentChar();
m_eCurToken = eCharVal;
m_tokAttrib.setAttribVal(val);
}
else
{
m_eCurToken = eUnknown;
}
break;
}
return m_eCurToken;
}
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I like to explore different aspects of technology. Try new things, and get delighted. My interests are programming language, and Imaging. But its not hard to work on other things also. Algorithms delight me over a coffee break.
I basically code in C++, but JAVA is not so alien for me. I know few scripting languages also. Basically I feel that knowing a programing language is just a matter of getting introduced to it.
For my other articles check my blog on homepage:
http://brainlesslabs.com/
https://github.com/BrainlessLabsInc
http://www.luxrender.net/en_GB/authors_contributors - SMISRA