trangrammar.cpp

这是编译原理编译器中的一部分

#include <sstream>
#include "parse.h"
#include "read.h"

extern ifstream grammarfile;
extern DVec_str productions;
extern vecStr terminals;
extern vecNter nonterminals;

void readGrammar(void)
{    
	 string name =  "grammar.txt";
	 Nonterminal nonterminal;

	 grammarfile.open( name.c_str() );
	if( !grammarfile ) cout << "Cannot open the source grammar file!";

	ofstream outf( "tokens.txt" );
    if( !outf ) cout << "Cannot open the file " << "token.txt!\n";

	readfile(grammarfile,productions);

	for(size_t i = 0;i < productions.size();i++)                                               // make the nonterminals
	{
		nonterminal.token = productions[i][0];
		if( !hasexisted( nonterminals,nonterminal ) ) nonterminals.push_back( nonterminal );
	}

	for(size_t i = 0;i < productions.size();i++)                                               //make the terminals
		for(size_t j = 1;j < productions[i].size() ;j++)
		{
			nonterminal.token = productions[i][j];
		    if( !hasexisted(terminals,productions[i][j]) &&  !hasexisted(nonterminals,nonterminal)  )
				terminals.push_back(productions[i][j] );
		}
	outf <<"The terminals has:\n";
	for(size_t i=0;i<terminals.size();i++)
		outf<<terminals[i]<<"\n";

	outf <<"\n\nThe nonterminals has:\n";
	for(size_t i=0;i<nonterminals.size();i++)
		outf<<nonterminals[i].token<<"\n";
	outf.close();

	name = "grammar_tran.txt";outf.open( name.c_str() );
	if( !outf ) cout << "Cannot open the file gmar_no|.txt!\n";
	else printPro( outf );
	

}

bool hasexisted( vector< string>   vec ,string str )
{
	size_t i;
	for(i = 0;i < vec.size() && str != vec[i];i++);
	return  i == vec.size() ? false : true;
}

bool hasexisted( vector< Nonterminal >  vec ,Nonterminal n)
{
	size_t i;
	for(i = 0;i < vec.size() && n.token != vec[i].token;i++);
	return  i == vec.size() ? false : true;
}

void readfile(ifstream &inf,DVec_str &productions)
{
		string str,strline;
		
		while( getline(inf,strline) )
		{
			vecStr production; 
			istringstream sin( strline );
			while( sin >> str )
			{
				if( str !="→" && str != "|"  )
					production.push_back( str );
				else if( str == "→" ) ;//sin.seekg(1,ios_base::cur );
				else 
				{
					productions.push_back( production );
					str = production[0];
					production.clear();
					production.push_back(str );
				}	
			}
			productions.push_back( production );
		}
}

void printPro(ofstream &outf )
{
	for(size_t i = 0;i < productions.size();i++)
	{
		outf << productions[i][0] << " → " ;
		for( size_t j = 1;j < productions[i].size();j++)
		{
			outf << productions[i][j] << " ";
		}
		outf << endl;
	}
}