structk.~pa

编译原理-文法等价转换

    now:=wordlist;
  end;
procedure fensensi.setflag(f:boolean);
begin
  now.setflag(f);
end;
function fensensi.get:sword;
  var temp:string;
  begin
   { temp:=form1.findname(now^.index);
    get.name:=temp;}
    get.index:=now.index;
    get.res:=now.res;
  end;
function fensensi.next:boolean;
  begin
    if now.link =nil
      then
        begin
          next:=true;
        end
      else
        begin
          now:=now.link;
          next:=false;
        end;
  end;
 function fensensi.pre:boolean;
   var temp:mfuhao;
   begin
     temp:=wordlist;
     if temp=now
       then
         begin
           pre:=true;
         end
       else
         begin
           while temp.link<>now do
             temp:=temp.link;
           now:=temp;
           pre:=false;
         end;
   end;
 function fensensi.ifeof:boolean;
   begin
     if now.link=nil
       then
         begin
           ifeof:=true;
         end
       else
         begin
           ifeof:=false;
         end;
   end;

function fensensi.add(index:integer):boolean;
  var temp:mfuhao;
  begin
    if wordlist.link=nil
      then
        begin
          wordlist.link:=Mfuhao.init(index);
          now:=wordlist;
          add:=true;
        end
      else
        begin
          temp=now;
          now:=wordlist.link;
          while (now.link<>nil) and (now.index<>index) do
            begin
              now:=now.link;
            end;
          if now.index<>index
            then
              begin
                while (now.link<>nil)  do
                  begin
                    now:=now.link;
                  end;
                now.link:=Mfuhao.init(index);
                add:=true;
              end
            else
              begin
                add:=false;
              end;
          now=temp;
        end;
  end;
function fensensi.ifhave(index:integer):boolean;
begin
  if (wordlist=nil) or (wordlist.link=nil)
    then
      begin
        ifhave:=false;
        exit;
      end;
  now:=wordlist.link;
  while (now.link<>nil) and (now.index<>index) do
    begin
      now:=now.link;
    end;
 ifhave:=(now.index=index);
end;
procedure fensensi.clear;
var temp:Mfuhao;
begin
  now:=wordlist;
  while now.link<>nil do
    begin
      temp:=now;
      now:=now.link;
      temp.done;
    end;
  now.done;
  wordlist:=nil;
  now:=nil;
end;
procedure fensensi.emtry;
  var temp:Mfuhao;
  begin
    now:=wordlist.link;
    if now<>nil
      then
        begin
         while (now.link<>nil) do
           begin
             temp:=now.link;
             now.done;
             now:=temp;
           end;
          now.done;
        end;
     now:=wordlist;
     now.link:=nil;
  end;
  function fensensi.getcanssi:string;
    var temp:string;
        temp1:string;
    begin
      temp:='';
      now:=wordlist;
      while now.link<>nil do
        begin
          temp1:=form1.findname(now.index);
          temp:=temp+' '+temp1;
          now:=now.link;
        end;
      temp1:=form1.findname(now.index);
      temp:=temp+' '+temp1;
      getcanssi:=temp;
    end;
    function fensensi.getnewcanssi:string;
    var temp:string;
        temp1:string;
    begin
      temp:='';
      now:=wordlist;
      while now.link<>nil do
        begin
          temp1:=form1.findnewname(now.index);
          temp:=temp+' '+temp1;
          now:=now.link;
        end;
      temp1:=form1.findnewname(now.index);
      temp:=temp+' '+temp1;
      getnewcanssi:=temp;
    end;

  function fensensi.isequal(p:fensensi):boolean;     (*针对单产生式对象,判断两产生式是否相同,相同返回TRUE*)
  begin
    p.setsi;
    setsi;
    while (get.index=p.get.index) and not(ifeof) and not(p.ifeof) do
      begin
        next;
        p.next;
      end;
    if (get.index=p.get.index) and (p.ifeof) and (ifeof)
      then
        begin
          isequal:=true;
        end
      else
        begin
          isequal:=false;
        end;
  end;
function fensensi.isequal2(p:fensensi):boolean;  (*针对集合对象,判断两集合式是否相同,相同返回TRUE*)
begin
  if p.getcount<>getcount
    then
      begin
        isequal2:=false;
        exit;
      end;
  p.setsi;
  while not p.next do
    begin
      if not ifhave(p.now.index)
        then
          begin
            isequal2:=false;
            exit;
          end;
    end;
  isequal2:=true;
end;
function fensensi.getcount:integer;
var i:integer;
begin
  setsi;
  i:=0;
  while not next do
    begin
      i:=i+1;
    end;
  getcount:=i;
end;
function fensensi.setposition(p:integer):boolean;
var i:integer;
begin
  setsi;
  i:=1;
  while (i<p) and not(ifeof) do
    begin
      next;
      i:=i+1;
    end;
   if i=p
     then
       setposition:=true
     else  setposition:=false;
 end;
function fensensi.sub(index:integer):boolean;(*针对集合类型,减去一个元素,若无这个元素返回FALSE*)
var temp:mfuhao;
begin
  now:=wordlist;
  temp:=now;
  now:=now.link;
  while (now<>nil) and (now.index<>index) do
    begin
      temp:=now;
      now:=now.link;
    end;
  sub:=now<>nil;
  if now<>nil
    then
      begin
        temp.link:=now.link;
        now.done;
        now:=wordlist;
      end;
end;
function fensensi.subfuhao(index:integer):boolean;(*针对产生式类型,减去一个元素,减后为空返回TRUE*)
var temp:mfuhao;
begin
  now:=wordlist;
  repeat
    if now.index=index
      then
        begin
          if now=wordlist
            then
              begin
                wordlist:=wordlist.link;
                now.done;
                now:=wordlist;
                temp:=now;
              end
            else
              begin
                temp.link:=now.link;
                now.done;
                now:=temp.link;
              end;
        end
      else
        begin
          temp:=now;
          now:=now.link;
        end;
  until now=nil;
  if wordlist=nil
    then subfuhao:=true
    else subfuhao:=false;
end;
function fensensi.change(cs:cansenjh;var acount:integer):fensensi;
   (*在消除左递归中替换第一个非终结符,返回替换产生的最后的产生式*)
var temp:Mfuhao;
    temp1:Mfuhao;
    i:integer;
    f,f1:fensensi;
begin
  temp:=wordlist;
  i:=cs.gofuhao(now.index);
  cs.cans[i].setsi(1);
  wordlist:=mfuhao.init(cs.cans[i].now.get.index);
  now:=wordlist;
  while not cs.cans[i].now.next do
    begin
      now.link:=mfuhao.init(cs.cans[i].now.get.index);
      now:=now.link;
    end;
  temp1:=temp.link;
  add2(temp1);
  f:=self;
  f1:=link;
  acount:=0;
  while not cs.cans[i].next do
    begin
      acount:=acount+1;
      f.link:=fensensi.init3(cs.cans[i].now);
      temp1:=temp.link;
      f.link.add2(temp1);
      f:=f.link;
    end;
  f.link:=f1;
  change:=f;
  temp1:=temp.link;
  while temp1<>nil do
    begin
      temp.done;
      temp:=temp1;
      temp1:=temp.link;
    end;
  temp.done;
 end;
procedure fensensi.add2(p:mfuhao);
var temp:mfuhao;
begin
  now:=wordlist;
  while now.link<>nil do
    begin
      now:=now.link;
    end;
  temp:=p;
  while temp<>nil do
    begin
      now.link:=mfuhao.init(temp.index);
      now:=now.link;
      temp:=temp.link;
    end;

end;
  (*****************************************)
Constructor cansensi.init(cansi:string);
  var temp:string;
      i:integer;
      oldch:char;
      j:integer;
  begin
    scansisi:=nil;
    now:=nil;
    oldch:='c';
    i:=1;
    count:=0;
    temp:='';
    while (cansi[i]<>'=') and (i<=length(cansi))do
      begin
        if cansi[i]<>' '
          then begin
            temp:=temp+cansi[i];
          end;
        i:=i+1;
      end;
    i:=i+1;
    j:=form1.findindex(temp);
    parent:=mfuhao.init(j);
    first:=fensensi.init2(j);
    fellow:=fensensi.init2(j);
    synch:=fensensi.init2(j);
    temp:='';
    while i<=length(cansi) do
      begin
        case cansi[i] of
          '\': begin
                 if oldch='\'
                   then
                     begin
                       temp:=temp+'\';
                       oldch:='a';
                     end
                   else
                     begin
                       oldch:='\';
                     end;
               end;
          '|': begin
                 if oldch='\'
                   then
                     begin
                       temp:=temp+'|';
                       oldch:='|';
                     end
                   else
                     begin
                       if temp<>''
                         then
                           begin
                             if  scansisi=nil
                               then
                                 begin
                                   scansisi:=fensensi.init(temp);
                                   now:=scansisi;
                                   entercan:=fensensi.init2(parent.index);
                                   enternow:=entercan;
                                   count:=1;
                                 end
                                else
                                  begin
                                    now.link:=fensensi.init(temp);
                                    now:=now.link;
                                    enternow.link:=fensensi.init2(parent.index);
                                    enternow:=enternow.link;
                                    count:=count+1;
                                  end;
                              temp:='';
                            end;
                      end;
                end;
          else  begin
                  temp:=temp+cansi[i];
                end;
         end;
        i:=i+1;
      end;
    if temp<>''
      then
        begin
          if  scansisi=nil
            then
              begin
                scansisi:=fensensi.init(temp);
                now:=scansisi;
                entercan:=fensensi.init2(parent.index);
                enternow:=entercan;
                count:=1;
              end
            else
              begin
                now.link:=fensensi.init(temp);
                now:=now.link;
                enternow.link:=fensensi.init2(parent.index);
                enternow:=enternow.link;
                count:=count+1;
              end;
        end;
  end;
 Constructor cansensi.init2(p:integer);
 begin
   parent:=Mfuhao.init(p);
   first:=fensensi.init2(0);
   fellow:=fensensi.init2(0);       (*FIRST,FELLOW集合*)
   synch:=fensensi.init2(0);              (*同步化入口集合*)
   entercan:=nil;           (*入口集合链,链长与scansisi一样长,于scansisi对应位置为进入这个产生式的符号集*)
   enternow:=nil;           (*指向入口集合链某个位置指针*)
   scansisi:=nil;           (*单产生式链*)
   now:=nil;                (*指向单产生式链某个位置指针*)
   count:=0;
 end;
 COnstructor cansensi.init3(p:cansensi);   (*复制*)
 begin
   parent:=Mfuhao.init(p.parent.index);
   first:=fensensi.init2(0);
   fellow:=fensensi.init2(0);
   synch:=fensensi.init2(0);
   p.setsi(1);
   scansisi:=fensensi.init3(p.scansisi);
   entercan:=fensensi.init2(0);
   now:=scansisi;
   enternow:=entercan;
   while not p.next do
     begin
       now.link:=fensensi.init3(p.now);
       enternow.link:=fensensi.init2(0);
       now:=now.link;
       enternow:=enternow.link;
     end;
  count:=p.count;
 end;
 Procedure cansensi.add(p:fensensi;i:integer);
 var temp:fensensi;
     ifexit:boolean;
 begin
   temp:=fensensi.init4(p,i);
   if temp.wordlist=nil
     then
       begin
         temp.done;
       end
     else
       begin
         if scansisi=nil
           then
             begin