k7scan1.cpp von Schäfer
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Jonny007-MKD
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344
GDE_3_2008/k7scan1.cpp
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344
GDE_3_2008/k7scan1.cpp
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// k7scan1.cpp : Definiert den Einsprungpunkt für die Konsolenanwendung.
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//
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#include "stdafx.h"
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#pragma warning(disable:4786)
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#include <string>
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#include <map>
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using namespace std;
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#define Getc(s) getc(s)
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#define Ungetc(c) {ungetc(c,IP_Input); ugetflag=1;}
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/*
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* Lexical analyzer states.
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*/
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enum lexstate{L_START,L_INT,L_IDENT,L_STRING,L_STRING2,
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L_COMMENT,L_TEXT_COMMENT,L_LINE_COMMENT,L_END_TEXT_COMMENT};
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const int STRING1=3;
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const int IDENTIFIER=4;
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const int INTEGER1=5;
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const int TOKENSTART=300;
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class CParser
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{
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public:
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string yytext; //input buffer
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struct tyylval{ //value return
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string s; //structure
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int i;
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}yylval;
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FILE *IP_Input; //Input File
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FILE *IP_Error; //Error Output
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FILE *IP_List; //List Output
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int IP_LineNumber; //Line counter
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int ugetflag; //checks ungets
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int prflag; //controls printing
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map<string,int> IP_Token_table; //Tokendefinitions
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map<int,string> IP_revToken_table; //reverse Tokendefinitions
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int CParser::yylex(); //lexial analyser
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void CParser::yyerror(char *ers); //error reporter
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int CParser::IP_MatchToken(string &tok); //checks the token
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void CParser::InitParse(FILE *inp,FILE *err,FILE *lst);
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int CParser::yyparse(); //parser
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void CParser::pr_tokentable(); //test output for tokens
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void CParser::IP_init_token_table(); //loads the tokens
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void CParser::Load_tokenentry(string str,int index);//load one token
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void CParser::PushString(char c); //Used for dtring assembly
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CParser(){IP_LineNumber = 1;ugetflag=0;prflag=0;}; //Constructor
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};
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//------------------------------------------------------------------------
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// Adds a character to the string value
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void CParser::PushString(char c)
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{
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yylval.s += c;
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}
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//------------------------------------------------------------------------
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void CParser::Load_tokenentry(string str,int index)
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{
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IP_Token_table[str]=index;
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IP_revToken_table[index]=str;
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}
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void CParser::IP_init_token_table()
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{
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Load_tokenentry("STRING1",3);
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Load_tokenentry("IDENTIFIER",4);
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Load_tokenentry("INTEGER1",5);
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int ii=TOKENSTART;
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Load_tokenentry("AND",ii++);
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Load_tokenentry("OR",ii++);
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Load_tokenentry("Begin",ii++);
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Load_tokenentry("End",ii++);
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}
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//------------------------------------------------------------------------
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void CParser::pr_tokentable()
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{
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typedef map<string,int>::const_iterator CI;
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const char* buf;
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printf( "Symbol Table ---------------------------------------------\n");
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for(CI p=IP_Token_table.begin(); p!=IP_Token_table.end(); ++p){
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buf = p->first.c_str();
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printf(" key:%s", buf);
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printf(" val:%d\n", p->second);;
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}
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}
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//------------------------------------------------------------------------
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int CParser::yyparse()
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{
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int tok;
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if(prflag)fprintf(IP_List,"%5d ",(int)IP_LineNumber);
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/*
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* Go parse things!
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*/
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while ((tok=yylex())!=0){
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printf("%d ",tok);
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if(tok==STRING1)
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printf("%s %s ",IP_revToken_table[tok].c_str(),yylval.s.c_str());
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else
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if(tok==INTEGER1)
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printf("%s %d ",IP_revToken_table[tok].c_str(),yylval.i);
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else
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if(tok==IDENTIFIER)
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printf("%s %s ",IP_revToken_table[tok].c_str(),yylval.s.c_str());
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else
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if(tok>=TOKENSTART)
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printf("%s ",IP_revToken_table[tok].c_str());
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else
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printf("%c ",tok);
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if(!prflag)printf("\n");
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}
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return 0;
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}
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//------------------------------------------------------------------------
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/*
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* Parse Initfile:
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*
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* This builds the context tree and then calls the real parser.
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* It is passed two file streams, the first is where the input comes
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* from; the second is where error messages get printed.
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*/
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void CParser::InitParse(FILE *inp,FILE *err,FILE *lst)
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{
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/*
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* Set up the file state to something useful.
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*/
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IP_Input = inp;
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IP_Error = err;
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IP_List = lst;
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IP_LineNumber = 1;
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ugetflag=0;
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/*
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* Define both the enabled token and keyword strings.
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*/
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IP_init_token_table();
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}
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//------------------------------------------------------------------------
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/*
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* yyerror:
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*
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* Standard error reporter, it prints out the passed string
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* preceeded by the current filename and line number.
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*/
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void CParser::yyerror(char *ers)
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{
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fprintf(IP_Error,"line %d: %s\n",IP_LineNumber,ers);
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}
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//------------------------------------------------------------------------
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int CParser::IP_MatchToken(string &tok)
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{
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int retval;
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if( IP_Token_table.find(tok) != IP_Token_table.end()){
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retval = (IP_Token_table[tok]);
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}else{
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retval = (0);
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}
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return retval;
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}
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//------------------------------------------------------------------------
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/*
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* yylex:
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*
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*/
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int CParser::yylex()
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{
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//Locals
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int c;
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lexstate s;
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/*
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* Keep on sucking up characters until we find something which
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* explicitly forces us out of this function.
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*/
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for (s = L_START; 1;){
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c = Getc(IP_Input);
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yytext = yytext + (char)c;
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if(!ugetflag) {
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if(c != EOF)if(prflag)fprintf(IP_List,"%c",c);
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}else ugetflag = 0;
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switch (s){
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//Starting state, look for something resembling a token.
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case L_START:
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if (isdigit(c)){
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s = L_INT;
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}else if (isalpha(c) || c == '\\' ){
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s = L_IDENT;
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}else if (isspace(c)){
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if (c == '\n'){
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IP_LineNumber += 1;
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if(prflag)
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fprintf(IP_List,"%5d ",(int)IP_LineNumber);
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}
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yytext = "";
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}else if (c == '/'){
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yytext = "";
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s = L_COMMENT;
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}else if (c == '"'){
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s = L_STRING;
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}else if (c == EOF){
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return ('\0');
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}else{
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return (c);
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}
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break;
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case L_COMMENT:
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if (c == '/')
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s = L_LINE_COMMENT;
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else if(c == '*')
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s = L_TEXT_COMMENT;
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else{
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Ungetc(c);
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return('/'); /* its the division operator not a comment */
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}
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break;
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case L_LINE_COMMENT:
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if ( c == '\n'){
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s = L_START;
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Ungetc(c);
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}
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yytext = "";
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break;
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case L_TEXT_COMMENT:
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if ( c == '\n'){
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IP_LineNumber += 1;
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}else if (c == '*')
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s = L_END_TEXT_COMMENT;
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yytext = "";
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break;
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case L_END_TEXT_COMMENT:
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if (c == '/'){
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s = L_START;
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}else{
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s = L_TEXT_COMMENT;
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}
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yytext = "";
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break;
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/*
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* Suck up the integer digits.
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*/
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case L_INT:
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if (isdigit(c)){
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break;
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}else {
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Ungetc(c);
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yylval.s = yytext.substr(0,yytext.size()-1);
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yylval.i = atoi(yylval.s.c_str());
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return (INTEGER1);
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}
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break;
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/*
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* Grab an identifier, see if the current context enables
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* it with a specific token value.
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*/
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case L_IDENT:
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if (isalpha(c) || isdigit(c) || c == '_')
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break;
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Ungetc(c);
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yytext = yytext.substr(0,yytext.size()-1);
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yylval.s = yytext;
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if (c = IP_MatchToken(yytext)){
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return (c);
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}else{
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return (IDENTIFIER);
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}
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/*
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* Suck up string characters but once resolved they should
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* be deposited in the string bucket because they can be
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* arbitrarily long.
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*/
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case L_STRING2:
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s = L_STRING;
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if(c == '"'){
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PushString((char)c);
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}else{
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if(c == '\\'){
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PushString((char)c);
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}else{
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PushString((char)'\\');
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PushString((char)c);
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}
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}
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break;
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case L_STRING:
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if (c == '\n')
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IP_LineNumber += 1;
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else if (c == '\r')
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;
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else if (c == '"' || c == EOF){
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return (STRING1);
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} else if(c=='\\'){
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s = L_STRING2;
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//PushString((char)c);
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}else
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PushString((char)c);
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break;
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default: printf("***Fatal Error*** Wrong case label in yylex\n");
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}
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}
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}
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//------------------------------------------------------------------------
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int main(int argc, char* argv[])
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{
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FILE *inf;
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char fistr[100];
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printf("Enter filename:\n");
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gets(fistr);
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inf = fopen(fistr,"r");
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if(inf==NULL){
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printf("Cannot open input file %s\n",fistr);
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return 0;
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}
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CParser obj;
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obj.InitParse(inf,stderr,stdout);
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// obj.pr_tokentable();
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obj.yyparse();
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return 0;
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}
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