grammer.cpp

语法分析程序 实现C语言的语法分析过程

/*//此文件是读入规格化文法的类，即读入可到达的产生式
typedef struct GRAMMER
{
	string leftLabel;
	vector<string> vc_rightLable;
};
class Grammer
{
	private:
		vector<GRAMMER> vc_grammer;
		ifstream in;
	public:
		Grammer(const char filename[]);
		vector<string> getProduce(int pos);
		void push(GRAMMER gr);
		~Grammer(){};	
};*/

#include "main.h"

using namespace std;
Grammer::Grammer(const char filename[])
{   
	int line;
	bool b_l=false;
	in.open(filename,ios_base::in);
	if(!in) 
	{
		cerr<<"open file"<<filename<<"error\n"; 
		exit(1);
	}
	in>>line;
	this->line=line;
	cout<<"Line="<<this->line<<endl;
	for(int i=0;i<line;i++)
	{
		GRAMMER gram;
		string s;
		while(in>>s)
		{
			if(s==":") continue;
			if(s[0]=='$') 
			{   
				gram.leftLabel=s.substr(1,s.size()-1);
			}
			else if(s[s.size()-1]=='$') 
			{
				s.erase(s.size()-1);
				gram.vc_rightLable.push_back(s);
				push(gram);
				break;
			}
			else gram.vc_rightLable.push_back(s);
		}
	}
	in.close();
}
GRAMMER Grammer::getProduce(unsigned int pos)
{

	if(pos<vc_grammer.size())
	{
		return vc_grammer[pos];
	}
	else cerr<<"get grammerProduce error\n";
}
void Grammer::push(GRAMMER gr)
{
	vc_grammer.push_back(gr);
}