20041016212439689.txt

#include<fstream>

                    getsym ( );
                 }
                 else  if  (strcmp (sym, "lparen")== 0)
     {
      if (num > amax)
       {  error (31);
        num=0;
       }
      gen ("lit", 0, num);
      getsym ( );
     }
                 else if (strcmp (sym, "lparen")== 0)
                          { getsym ();
                              insert ("rparen", fsys, &fsys1);
                              expression (fsys1, tx, lev);
                              if  (strcmp (sym, "rparen")== 0)
                                   getsym( );
                              else  error (22);
                           }*/
     test(fsys,facbegsys,23);
 }
}



/*-------------------vardeclaration (&dx, &tx, lev)---------------------*/

void vardeclaration(int * dx,int *tx,int lev)        file://very different with paper
{
   if (sym=="ident")
   {
    enter("variable",dx,tx,lev);
       getsym();
   }
   else error(4);
}


/* ---------vardeclaration(&dx,&tx,lev)-------------*/

/*vardeclaration(dx,tx,lev)
int *dx,*tx,lev;
{
 int i;
 if (sym=="ident")==0)
 {
  enter("variable",dx,tx,lev);
  getsym( );
  if (sym=="lparen")==0) 
  {                               file://dealing with daclaration of array
   getsym( );
   if (sym=="number")==0)
   {
    table[(*tx)].foot=num;
    i=num+1;
    getsym( );
    if (sym=="colon")==0)
    {
     getsym( );
     if (sym=="number")==0)
     {
      do
      {
       enter("variable",dx,tx,lev);
       table[(*tx)].foot=i;
       i++;
      }
      while (i<=num);
      getsym( );
      if (sym=="rparen")!=0) error(50);
      getsym( );
     }
     else error(50);
    }
    else error(50);
   }
   else error(50);
  }
 } 

 else error(4);
}*/



/*-----------------constdeclaration (&dx, &tx, lev)-----------*/

void constdeclaration(int *dx,int *tx,int lev)
{
 if (sym=="ident")
 {
  getsym( );
  if ((sym=="eql") || (sym=="becomes"))
  {
   if (sym=="becomes")
    error(1);
   getsym( );
   if (sym=="number")
   {
    enter("constant",dx,tx,lev);
    getsym( );

   }
   else error(2);
  }
  else error(3);
 }
 else error(4);
}


/*-----------------------------enter (k)-----------------------------------*/

void enter(string k,int *dx,int *tx,int lev)
{  
  (*tx)++;
     table[(*tx)].kind=k;
     table[(*tx)].name=id;
     if (k=="constant")
     {  if (num>amax)
          {  error(31);
    num=0;
          }
          table[(*tx)].val=num;
       }
       if (k=="variable")
       {
          table[(*tx)].level=lev;
          table[(*tx)].adr=(*dx);
          (*dx)++;
    file://table[(*tx)].foot=0;
       }
       if (k=="procedure")  table[(*tx)].level=lev;
}



/*--------------------------test (s1,s2, n)-----------------------------*/

void test(symset  s1,symset s2,int n)
{
#if 0
 cout<<"begin test\n";
 for(string * ips=s1.sy;(*ips)=="*")!=0; ips++){
  cout<<(*ips)<<"\n";
 }
 cout<<endl;
#endif
 if (in(sym,s1)==0)
 {
  cout<<"!!"<<sym<<"!!"<<endl;
  error(n);
  while ((in(sym,s1)==0)&&(in(sym,s2)==0)&&ch!='.')
   getsym( );
 }
}



/*---------------------------gen (x,y,z)-----------------------------*/

file://void gen(char x[5],int y,int z)
void gen(string x, int y, int z)
{
 if (cx>cxmax)
 {
  cout<<"program too long !\n";
  exit(0);
 }
 file://strcpy(x,code[cx].f);
 code[cx].f=x;
 code[cx].l=y;
 code[cx].a=z;
 cx++;    
}




/*-----------------------------getsym ( )------------------------------*/

void getsym()
{
 int i,j,k;
 bool isblank=(ch==' '||ch=='\n'||ch=='\t'||'\r');
 while (isblank&&ch!='.'){
  getch();
  isblank=(ch==' '||ch=='\n'||ch=='\t'||ch=='\r');
 }

 if(ch==EOF||ch=='.')return;
 bool find=false;
 char * tp=new char[al];
 if ((ch>='a')&& (ch<='z'))       
 {
  k=0-1;
  id=string();
  do
  { int p;
   if (k<al)
   {
    k++;
    a[k]=ch;
    id.push_back(ch);
   }
   getch( );
  } while ((ch>='a')&&(ch<='z')||(ch>='0')&&(ch<='9')); 

  ptext--;


  i=1;
  j=norw;
   
  for(k=i;k<i+j;k++){
   if  (id==word[k]){
   sym=wsym[k];
   find=true;
   break;
   }
  } 

 
  if(!find){
   sym="ident";
  }

  return;

 }

 if ((ch>='0')&&(ch<='9')){//combine a number
 k=0;
 num=0;
 sym="number";
 do {
  num=10*num+ch-'0';
  k++;
  getch( );
 } while ((ch>='0')&&(ch<='9'));
 ptext--;
  if (k>nmax)
  error(30);

 return;
 }


 
 file://not a-z and not 0-9
 if (ch=='='){
  sym="eql";
  file://getch( );
  return;
 }
 

 if (ch==':'){
  getch( );
  if (ch=='='){
   sym="becomes";
  // getch( );
  }
   else
   sym="nul";  
  return;
 }
 
       
     if (ch=='<'){
         getch( );
  if (ch=='='){
            sym="leq";
           // getch( );
  }
         else sym="lss";
 return;
 }
    
     if (ch=='>'){
  getch( );
  if (ch=='='){
   sym="geq";
  // getch();
  }
  else sym="gtr";
 return;
 }
    
   sym=what_identify(ch);
      //  getch( );

 
}



/*----------------------------getch ( )------------------------*/

void getch()       
{
 ch=text[ptext++];

}




/*-------------------error(n)------------*/
void error(int n)
{ 
 int i=0;
 printf("*****");
 printf("%2d",n) ;
 err++;
}


/*--------------------listcode (cx0)-----------------------*/
void listcode(int cx0)
{
 int i;
 if (listswitch==1)
  for (i=cx0-1;i<cx;i++)    /*has  been   changed  */
   printf("%4d%5s%3d%5d\n",i,code[i].f.c_str(),code[i].l,code[i].a);
}


/*-----------------------------insert (symi,fsys,&fsysi)--------------------*/
void insert(string sym1,symset fsys,symset *fsys1)
{
 int i=0;
 if (fsys1==0)
  fsys1=(symset *)calloc(30,sizeof(symset));
 while (fsys.sy[i]!="*")
 {
  (*fsys1).sy[i]=fsys.sy[i];
  i++;
 }
 (*fsys1).sy[i]=fsys.sy[i];
 i=0;
 while (sym1!=(*fsys1).sy[i] && (*fsys1).sy[i]!="*")
  i++;
 if (sym1!=(*fsys1).sy[i])
 {
  (*fsys1).sy[i]=sym1;
  i++;
  (*fsys1).sy[i]="*";
 }
}



/*--------------------------------int in (sm,fsys)--------------------*/
int in(string sm,symset fsys)
{
 int i;
 i=0;
 while (sm!=fsys.sy[i] && fsys.sy[i]!="*")
  i++;
 if (sm==fsys.sy[i])
  i=1;
 else
  i=0;
 return(i);
}





/*------------------------------int position (id,tx)------------------*/
int position(string id,int tx)
{
 int i;
 table[0].name=id;
 i=tx;
 while (table[i].name!=id)
  i--;
 return(i);
}







/*----------------------int ifarr-----------------------*/
/*int ifarr(fsys,tx,lev,tt)
symset fsys;
int tx,lev,tt;
{
 string sm;
 if (table[tt].foot!=0)
 {
  strcpy(sm,table[tt].name);
  while (strcmp(table[tt].name,sm)==0)
   tt--;
  tt++;
  getsym();
  if (sym=="lparen")!=0)
   error(51);
  else
  {
   getsym();
   insert("rparen",fsys,&fsys);
   expression(fsys,tx,lev);
   if (sym=="rparen")!=0)
    error(52);
  }
 }
 else
  gen("lit",0,0);
 return(tt);
}
*/



/*-----------------------int base (l,b)------------------------*/
int base(int l,int b)
{
 int b1;
 b1=b;
 while (l>0)
 {
  b1=s[b1];
  l--;
 }
 return (b1);
}





/*-----------------------interpret() ------------------------*/
void interpret()
{
 int p,b,t;
 instruction i;
 printf("start pl/0 :\n");
 t=p=0;
 b=1;
 s[1]=s[2]=s[3]=0;
 do
 {
  i.a=code[p].a;
  i.l=code[p].l;
  i.f=code[p].f;
  p++;
  if (i.f=="lit")
  {
   t++;
   s[t]=i.a;
  }
  if (i.f=="opr")
  switch(i.a)
  {
   case 0:
    t=b-1;
    p=s[t+3];
    b=s[t+2];
    break;
   case 1:
    s[t]=0-s[t];
    break;
   case 2:
    t--;
    s[t]=s[t]+s[t+1];
    break;
   case 3:
    t--;
    s[t]=s[t]-s[t+1];
    break;
   case 4:
    t--;
    s[t]=s[t]*s[t+1];
    break;
   case 5:
    t--;
    s[t]=s[t]/s[t+1];
    break;
   case 6:
    if (s[t]!=0)
     s[t]=1;
    else s[t]=0;
    break;
   case 8:
    t--;
    if (s[t]==s[t+1])
     s[t]=1;
    else
     s[t]=0;
    break;
   case 9:
    t--;
    if (s[t]!=s[t+1])
     s[t]=1;
    else
     s[t]=0;
    break;
   case 10:
    t--;
    if (s[t]<s[t+1])
     s[t]=1;
    else
     s[t]=0;
    break;
   case 11:
    t--;
    if (s[t]>=s[t+1])
     s[t]=1;
    else
     s[t]=0;
    break;
   case 12:
    t--;
    if (s[t]>s[t+1])
     s[t]=1;
    else
     s[t]=0;
    break;
   case 13:
    t--;
    if (s[t]<=s[t+1])
     s[t]=1;
    else
     s[t]=0;
    break;
   case 14:
    cout<<s[t];
    t--;
    break;
   case 15:
    printf("\n");
    break;
   case 16:
    t++;
    cout<<"?";
    cin>>s[t];
    cout<<s[t];
    
    break;
   default:
    exit(0);
  }
  if (i.f=="lod")         file://defferent from paper
  {
   file://s[t]=s[base(i.l,b)+i.a+s[t]];
   t++;
   s[t]=s[base(i.l,b)+i.a];
  }
  if (i.f=="sto")          file://defferent from paper
  {
   file://s[base(i.l,b)+i.a+s[t-1]]=s[t];
   s[base(i.l,b)+i.a]=s[t];
   t--;  
  } 
  if (i.f=="cal")
  {
   s[t+1]=base(i.l,b);
   s[t+2]=b;
   s[t+3]=p;
   b=t+1;
   p=i.a;
  }
  if (i.f=="int")
   t=t+i.a;
  if (i.f=="jmp")
   p=i.a;
  if (i.f=="jpc")
   if (s[t]==0)
    p=i.a;
 } while (p!=0);
 cout<<"end pl/0 !\n";
}





/*---------------------------end--------------------*/
/*---------------------------result----------------*/

/*-----------------------------main( )-----------------------------------*/
void main()
{
  cout<<"input file ?";
   cin>>fname;
   cout<<fname<<endl;
   

   finf.open(fname.c_str());
 finf.unsetf(ios::skipws);
   file://printf(fopen(fname, "r"));
   cout<<"list code ? ";
   cin>>fname;
   cout<<fname<<endl;
   if (fname[0]=='y')
        listswitch=1;
   else
        listswitch=0;
   err=cc=ll=cx=ptext=0;
   kk=10;
   ch=' ';

 while (!finf.eof()){               
  finf>>ch; 
  cout<<ch;
  text.push_back(ch);
 }
   getsym();
   block(0,0,fsysa);
   if (sym!="period")
   //    error(9);
   if (err==0)
       interpret( );
   else
       printf("error in pl/0 program !\n");
}