table.cpp

一个语法分析程序,C++写的,内含原码和exe文件. 开发工具:DEV-C

/*
This part becomes simple after FIRST set and FOLLOW set
are constructed 
   finished on  6.8 
        Math Frog
*/
#include "global.h"

string LL1_table[MAXSIZE][MAXSIZE]; // import
list<string> tmpfirst; // for holding first set of alpha
bool isLL1Grammer;
void initTable() // initialize the LL1_table
{
   list<string>::iterator iter;
   LL1_table[0][0] = "M[VN,VT]"; 
   int row = 1,col = 1;
  
    for(iter = VN.begin();iter != VN.end();iter++)
         LL1_table[row++][0] = *iter;
    for(iter = VT.begin();iter != VT.end();iter++)
        LL1_table[0][col++] = *iter;
        LL1_table[0][col] = "$" ; // make $ a terminal
  // for decide the position
}
void buildTable()
{
list<string>::iterator iter,it,copy;
string hold;
int save,pos;
int row,col; // for adding element to the table ... 
  for(int line = 0;line < colineno;line++){
     // compute A->X1X2...Xn
      iter = coProduction[line].begin();
      hold = *iter;// save for searching
    for(row = 1;row <= VN.size();row++)
       if(LL1_table[row][0] == hold) break; // find the current non-terminal in the table
    for(int i = 0;i < VN.size();i++)
       if(hold == symbol[i].name) 
          {pos = i;break;}  // in the symbol ... 
      iter++;iter++; // to the right
      it = iter; // begin finding
  ////computing the first set of alpha ///////////////
   while(it != coProduction[line].end()){
      if(isIn(*it,VT) || *it == ee) // the current symbol is a terminal
        {tmpfirst.push_back(*it);break;} // because terminal's first set has no e in 
                                         // so the computation ends or in the last
       else{ // is not a terminal
          for(int i = 0;i < VN.size();i++) 
             if(*it == symbol[i].name)
                 {save = i;break;}
       for(copy = symbol[save].first.begin();copy != symbol[save].first.end();copy++)
           if(!isIn(*copy,tmpfirst))
             tmpfirst.push_back(*copy); // to copy 
        } 
        if(!isIn(ee,tmpfirst)) break; // symbol[save]'s first has no e ,to end
                                        // the computation... 
        it++;
      }
     ///////////////////////////////////////////////
     // scan alpha's first set... 
   for(it = tmpfirst.begin();it != tmpfirst.end();it++)
     if(isIn(*it,VT)){ // the current symbol is a terminal
      // then add A->alpha to LL1_table[A][alpha]
      // decide the position
       for(col = 1;col <= VT.size() + 1;col++)  
          if(*it == LL1_table[0][col]) break;
        listToString(LL1_table[row][col],coProduction[line]);
      }
      if(isIn(ee,tmpfirst)){ // if the empty string is in the FIRST(X1X2..Xn)
    for(it = symbol[pos].follow.begin();it != symbol[pos].follow.end();it++)
           if(isIn(*it,VT) || *it == "$"){
             if(*it == "$") 
         listToString(LL1_table[row][VT.size() + 1],coProduction[line]);
           else{
             for(col = 1;col <= VT.size() + 1;col++)
             if(*it == LL1_table[0][col]) break;
              listToString(LL1_table[row][col],coProduction[line]);
             }
           }
         }
      tmpfirst.erase(tmpfirst.begin(),tmpfirst.end()); 
     }
   for(row = 1;row <= VN.size();row++)
     for(col = 1;col <= VT.size() + 1;col++)  
       if(LL1_table[row][col].empty())
         LL1_table[row][col] = "Error";
   }
void printTable()
{ 
  int row ,col;
   cout << "***********************************" << endl;
   cout << "** The LL(1) Table is as follow **" << endl;
    cout << "***********************************" << endl;
  for(row = 1;row <= VN.size();row++){
    for(col = 1;col <= VT.size() + 1;col++){
  cout << " |**  M[ " << LL1_table[row][0] << ", " << LL1_table[0][col] << " ] = ";
  cout << LL1_table[row][col] << "\t";
  cout << "   **|" << endl;
}
  }
     cout << "***********************************" << endl;
}