C++ parser
$40 USD
Pago na entrega
#include "p2lex.h"
#include <string>
#include <istream>
#include <fstream>
using namespace std;
/////////
//// this class can be used to represent the parse result
//// the various different items that the parser might recognize can be
//// subclasses of ParseTree
class ParseTree {
private:
ParseTree *leftChild;
ParseTree *rightChild;
int whichLine;
public:
ParseTree(ParseTree *left = 0, ParseTree *right = 0) : leftChild(left),rightChild(right) {
whichLine = linenum;
}
int onWhichLine() { return whichLine; }
};
//// for example, an integer...
class Integer : public ParseTree {
private:
Token iTok;
public:
Integer(const Token& iTok) : ParseTree(), iTok(iTok) {}
int getInteger() { return stoi( [login to view URL]() ); }
};
int linenum = 0;
int globalErrorCount = 0;
/// error handler
void error(string msg)
{
cout << linenum << ": " << msg << endl;
++globalErrorCount;
}
/// function prototypes
ParseTree *Program(istream *in);
ParseTree *StmtList(istream *in);
ParseTree *Stmt(istream *in);
ParseTree *Expr(istream *in);
ParseTree *Term(istream *in);
ParseTree *Primary(istream *in);
ParseTree *String(istream *in);
ParseTree *Program(istream *in)
{
ParseTree *result = StmtList(in);
// make sure there are no more tokens...
if( getToken(in).getTok() != DONE )
return 0;
return result;
}
ParseTree *StmtList(istream *in)
{
return 0;
}
ParseTree *Stmt(istream *in)
{
Token t;
t = getToken(in);
if( [login to view URL]() == PRINT ) {
// process PRINT
}
else if( [login to view URL]() == SET ) {
// process SET
}
else
error("Invalid statement");
return 0;
}
ParseTree *Expr(istream *in)
{
return 0;
}
ParseTree *Term(istream *in)
{
return 0;
}
ParseTree *Primary(istream *in)
{
Token t = getToken(in);
if( [login to view URL]() == ID ) {
}
else if( [login to view URL]() == INT ) {
return new Integer(t);
}
else if( [login to view URL]() == STR ) {
}
else if( [login to view URL]() == LPAREN ) {
ParseTree *ex = Expr(in);
if( ex == 0 )
return 0;
t = getToken(in);
if( [login to view URL]() != RPAREN ) {
error("expected right parens");
return 0;
}
return ex;
}
return 0;
}
ParseTree *String(istream *in)
{
return 0;
}
main()
{
ParseTree *prog = Program(&cin);
if( prog == 0 || globalErrorCount != 0 ) {
cout << "Parse failed, exiting" << endl;
return 0;
}
cout << "Success. Congrats!" << endl;
return 0;
}
ID do Projeto: #12161733
