structk.~pa

编译原理-文法等价转换

               scansisi:=temp;
               entercan:=fensensi.init2(0);
               now:=scansisi;
               count:=1;
             end
           else
             begin
               now:=scansisi;
               ifexit:=false;
               repeat
                 if now.isequal(temp)
                   then ifexit:=true;
                 now:=now.link;
               until (now=nil) or ifexit;
               if ifexit
                 then temp.done
                 else
                   begin
                     now:=scansisi;
                     enternow:=entercan;
                     while now.link<>nil do
                       begin
                         now:=now.link;
                         enternow:=enternow.link;
                       end;
                     now.link:=temp;
                     enternow.link:=fensensi.init2(0);
                     count:=count+1;
                   end;
             end;
       end;
 end;
 Procedure cansensi.add2(p:fensensi);
 begin
   if scansisi=nil
     then
       begin
         scansisi:=fensensi.init3(p);
         now:=scansisi;
         count:=1;
       end
     else
       begin
         now:=scansisi;
         while now.link<>nil do
           begin
             now:=now.link;
           end;
         now.link:=fensensi.init3(p);
         count:=count+1;
       end;
 end;
 Destructor  cansensi.Done;
   var temp:fensensi;
   begin
     now:=scansisi;
     enternow:=entercan;
     if first<>nil
       then  first.done;
     if fellow<>nil
       then  fellow.done;
     if parent<>nil
       then  parent.done;
     if synch<>nil
       then  synch.done;
     if now<>nil
       then
         begin
           while now.link<>nil do
             begin
               temp:=now.link;
               now.Done;
               now:=temp;
               if (enternow<>nil) and (enternow.link<>nil)
                 then
                   begin
                     temp:=enternow.link;
                     enternow.done;
                     enternow:=temp;
                   end;
             end;
          now.Done;
          if enternow<>nil
            then enternow.Done;
     end;
     inherited destroy;
   end;
 procedure cansensi.sunsetsi;
   begin
     now.setsi;
     enternow.setsi;
   end;
 procedure cansensi.setsi(index:integer);
   var i:integer;
   begin
     now:=scansisi;
     enternow:=entercan;
     i:=index;
     while i>1 do
       begin
         now:=now.link;
         if enternow<>nil
           then enternow:=enternow.link;
         i:=i-1;
       end;
     now.setsi;
     if enternow<>nil
       then enternow.setsi;
   end;
 function cansensi.get:sword;
   begin
     get.index:=now.get.index;
     get.res:=now.get.res;
   end;
 function cansensi.next:boolean;
  begin
    if now.link<>nil
      then
        begin
          now:=now.link;
          now.setsi;
          if enternow<>nil
            then
              begin
                enternow:=enternow.link;
                if enternow<>nil
                  then enternow.setsi;
              end;
          next:=false;
        end
      else
        begin
          next:=true;
        end;
  end;
 function cansensi.ifeof:boolean;
   begin
     if now.link=nil
       then ifeof:=true
       else ifeof:=false;
   end;
 function cansensi.sunnext:boolean;
  begin
    sunnext:=now.next;
    enternow.next;
  end;
 function cansensi.sunpre:boolean;
 begin
   sunpre:=now.pre;
   enternow.pre;
 end;

 function cansensi.sunifeof:boolean;
   begin
     sunifeof:=now.ifeof;
   end;
 procedure cansensi.setflag(f:boolean);
   begin
     now.setflag(f);
   end;

procedure cansensi.addfirst(index:integer);
  var j:integer;
  begin
    if first.add(index)
      then parent.res:=true;
  end;

procedure cansensi.addfellow(index:integer);
  var j:integer;
  begin
    if fellow.add(index)
      then parent.res:=true;
  end;
procedure cansensi.refreshff;
  begin
    first.emtry;
    fellow.emtry;
    synch.emtry;
    setsi(1);
    if enternow<>nil
       then
         begin
           while enternow.link<>nil do
             begin
               enternow.emtry;
               enternow:=enternow.link;
             end;
           enternow.emtry;
           enternow:=entercan;
         end;
  end;
function cansensi.getcanssi:string;
var temp:string;
    temp1:string;
begin
  temp:='';
  now:=scansisi;
  while now.link<>nil do
    begin
      temp:=temp+now.getcanssi+'|';
      now:=now.link;
    end;
  temp:=temp+now.getcanssi;
  temp1:=form1.findname(parent.index);
  temp:=temp1+'='+temp;
  getcanssi:=temp;
end;
function cansensi.getnewcanssi:string;
var temp:string;
    temp1:string;
begin
  temp:='';
  now:=scansisi;
  while now.link<>nil do
    begin
      temp:=temp+now.getnewcanssi+'|';
      now:=now.link;
    end;
  temp:=temp+now.getnewcanssi;
  temp1:=form1.findnewname(parent.index);
  temp:=temp1+'='+temp;
  getnewcanssi:=temp;
end;

function cansensi.subfuhao(index:integer):boolean;
var temp:fensensi;
    temp1:fensensi;
begin
  now:=scansisi;
  enternow:=entercan;
  repeat
    if now.subfuhao(index)
      then
        begin
          count:=count-1;
          if now=scansisi
            then
              begin
                scansisi:=scansisi.link;
                entercan:=entercan.link;
                now.done;
                enternow.done;
                now:=scansisi;
                enternow:=entercan;
              end
            else
              begin
                temp.link:=now.link;
                temp1.link:=enternow.link;
                now.done;
                enternow.done;
                now:=temp.link;
                enternow:=temp1.link;
              end;
        end
      else
        begin
          temp:=now;
          now:=now.link;
          temp1:=enternow;
          enternow:=enternow.link;
        end;
  until now=nil;
  if scansisi=nil
    then subfuhao:=true
    else subfuhao:=false;
end;
procedure cansensi.change(cs:cansenjh);      (*在消除左递归中替换第一个非终结符*)
var i:integer;
begin
  now:=now.change(cs,i);
  count:=count+i;
end;
function cansensi.change1(cs:cansenjh):integer;
var ifend:boolean;
    temp:cansensi;
    t1,t2,t3:fensensi;
    m:mfuhao;
begin
  now:=scansisi;
  now.setsi;
  ifend:=false;
  now.setsi;
  repeat
    if now.get.index=parent.index
      then ifend:=true;
    until next or ifend;
  if ifend
    then
      begin
        form1.fzjnumnew:=form1.fzjnumnew+1;
        form1.fzjfuhaonew[form1.fzjnumnew].name:='添加符号'+form1.findname(parent.index);
        form1.fzjfuhaonew[form1.fzjnumnew].index:=form1.fzjnumnew+300;
        temp:=cansensi.init2(form1.fzjnumnew+300);
        now:=scansisi;
        m:=mfuhao.init(form1.fzjnumnew+300);
        t2:=nil;
        while now<>nil do
          begin
            t1:=fensensi.init3(now);
            t1.add2(m);
            now.setsi;
            if now.get.index=parent.index
              then
                begin
                  if now.ifeof
                    then
                      begin
                        t1.done;
                        m.done;
                        temp.done;
                        change1:=-1*now.get.index;
                        exit;
                      end;
                  t1.subfuhao(parent.index);
                  temp.add2(t1);
                  t1.done;
                end
              else
                begin
                  if t2=nil
                    then
                      begin
                        t2:=t1;
                        t3:=t2;
                      end
                    else
                      begin
                        t3.link:=t1;
                        t3:=t3.link;
                      end;
                end;
            now:=now.link;
          end;
        now:=scansisi.link;
        while now<>nil do
          begin
            scansisi.done;
            scansisi:=now;
            now:=now.link;
          end;
        scansisi.done;
        scansisi:=t2;
        change1:=1;
        t2:=fensensi.init2(300);
        temp.add2(t2);
        t2.done;
        cs.add2(temp);
      end
    else
      begin
        change1:=0;
      end;

 end;
  (*****************************)
Constructor cansenjh.init;
  var i:integer;
  begin
    for i:=1 to 500 do
      begin
        cans[i]:=NIL;
      end;
    count:=0;
  end;
function   cansenjh.ifhave(index:integer):boolean;
var i:integer;
begin
  i:=1;
  while (i<=count) and (index<>cans[i].parent.index) do
    i:=i+1;
  if i>count
    then  ifhave:=false
    else  ifhave:=true;
end;
function  cansenjh.gofuhao(index:integer):integer;  (*返回左部为i的产生式号码*)
var i:integer;
begin
  i:=1;
  while (i<=count) and (index<>cans[i].parent.index) do
    i:=i+1;
  if i>count
    then gofuhao:=-1
    else gofuhao:=i;
end;
Destructor  cansenjh.done;
  var i:integer;
  begin
    for i:=1 to count do
      begin
        cans[i].done;
      end;
   inherited destroy;
  end;
procedure cansenjh.add(s:string);
  begin
    count:=count+1;
    cans[count]:=cansensi.init(s);
  end;
procedure cansenjh.add2(p:cansensi); (*增加产生式,注意p不要被删除*)
  begin
    count:=count+1;
    cans[count]:=p;
  end;
procedure cansenjh.add3(p:cansensi); (*增加产生式,P可以被删除*)
  begin
    count:=count+1;
    cans[count]:=cansensi.init3(p);
  end;
procedure cansenjh.exchange(h:integer;s:string);
  begin
    cans[h].done;
    cans[h]:=cansensi.init(s);
  end;
procedure cansenjh.delete(d:integer);
  var i:integer;
  begin
    if (d<count)
      then
        begin
          cans[d].done;
          for i:=d to count-1 do
            begin
              cans[i]:=cans[i+1];
            end;
            count:=count-1;
        end
      else
        begin
          if d=count
            then
              begin
                cans[d].done;
                count:=count-1;
              end;
        end;
  end;
(*****************************************)
constructor item.init(p:fensensi;par:mfuhao);  (*初始化项目,s 为单产生式,*)
begin
  p.setsi;
  inherited init3(p);
  parent:=mfuhao.init(par.index);
  position:=0;
  link:=nil;
  act.nextfuhao:=-1;
  act.act:=-1;
end;
constructor item.init2(p:item;o:integer);  (*初始化项目,p 为样本项目,o为位置*)
begin
  p.setsi;
  inherited init3(p);
  parent:=mfuhao.init(p.parent.index);
  position:=o;
  link:=nil;
  act.nextfuhao:=p.getaction.nextfuhao;
  act.act:=p.getaction.act;
end;
constructor item.init3(s:string);
   (*初始化项目,s为存盘信息 ,s 结构position (int),nextfuhao (string),act (int),parent(string),产生式 (string)*)
var i:integer;
    temp:string;
    p:integer;
begin
  wordlist:=nil;
  now:=nil;
  i:=1;
  temp:='';
  while (i<=length(s)) and (s[i]<>' ') do
    begin
      temp:=temp+s[i];
      i:=i+1;
    end;
  try
    p:=strtoint(temp);
  except
    act.act:=-3;
    exit;
  end;
  position:=p;
  temp:='';
  i:=i+1;
  while (i<=length(s)) and (s[i]<>' ') do
    begin
      temp:=temp+s[i];
      i:=i+1;
    end;
  if temp=''
    then
      begin
        act.act:=-3;
        exit;
      end;

  if temp='@@@@@@@@@@'
    then act.nextfuhao:=-1
    else
      begin