C++ cdr函数代码示例

// (kill 'pid ['cnt]) -> flg
any doKill(any ex) {
   pid_t pid;

   pid = (pid_t)evCnt(ex,cdr(ex));
   return kill(pid, isCell(cddr(ex))? (int)evCnt(ex,cddr(ex)) : SIGTERM)? Nil : T;
}

void isLastOperand(Register result, Register ops)
{
    cdr(result, ops);
    makeBoolean(result, isNull(result));
}

void procedureBody(Register result, Register procedure)
{
    cdr(result, procedure);
    cdr(result, result);
    car(result, result);
}

void isLastExp(Register result, Register exp)
{
    cdr(result, exp);
    makeBoolean(result, isNull(result));
}

void operands(Register result, Register exp)
{
    cdr(result, exp);
}

void lambdaBody(Register result, Register exp)
{
    cdr(result, exp);
    cdr(result, result);
}

void ifConsequent(Register result, Register exp)
{
    cdr(result, exp);
    cdr(result, result);
    car(result, result);
}

// (xor 'any 'any) -> flg
any doXor(any x) {
   bool f;

   x = cdr(x),  f = isNil(EVAL(car(x))),  x = cdr(x);
   return  f ^ isNil(EVAL(car(x)))?  T : Nil;
}

// (nil . prg) -> NIL
any doNil(any x) {
   while (isCell(x = cdr(x)))
      if (isCell(car(x)))
         evList(car(x));
   return Nil;
}

// (as 'any1 . any2) -> any2 | NIL
any doAs(any x) {
   x = cdr(x);
   if (isNil(EVAL(car(x))))
      return Nil;
   return cdr(x);
}

// (eval 'any ['cnt ['lst]]) -> any
any doEval(any x) {
   any y;
   cell c1;
   bindFrame *p;

   x = cdr(x),  Push(c1, EVAL(car(x))),  x = cdr(x);
   if (!isNum(y = EVAL(car(x))) || !(p = Env.bind))
      data(c1) = EVAL(data(c1));
   else {
      int cnt, n, i, j;
      struct {  // bindFrame
         struct bindFrame *link;
         int i, cnt;
         struct {any sym; any val;} bnd[length(x)];
      } f;

      x = cdr(x),  x = EVAL(car(x));
      j = cnt = (int)unBox(y);
      n = f.i = f.cnt = 0;
      do {
         ++n;
         if ((i = p->i) <= 0  &&  (p->i -= cnt, i == 0)) {
            for (i = 0;  i < p->cnt;  ++i) {
               y = val(p->bnd[i].sym);
               val(p->bnd[i].sym) = p->bnd[i].val;
               p->bnd[i].val = y;
            }
            if (p->cnt  &&  p->bnd[0].sym == At  &&  !--j)
               break;
         }
      } while (p = p->link);
      while (isCell(x)) {
         for (p = Env.bind, j = n; ; p = p->link) {
            if (p->i < 0)
               for (i = 0;  i < p->cnt;  ++i) {
                  if (p->bnd[i].sym == car(x)) {
                     f.bnd[f.cnt].val = val(f.bnd[f.cnt].sym = car(x));
                     val(car(x)) = p->bnd[i].val;
                     ++f.cnt;
                     goto next;
                  }
               }
            if (!--j)
               break;
         }
next:    x = cdr(x);
      }
      f.link = Env.bind,  Env.bind = (bindFrame*)&f;
      data(c1) = EVAL(data(c1));
      while (--f.cnt >= 0)
         val(f.bnd[f.cnt].sym) = f.bnd[f.cnt].val;
      Env.bind = f.link;
      do {
         for (p = Env.bind, i = n;  --i;  p = p->link);
         if (p->i < 0  &&  (p->i += cnt) == 0)
            for (i = p->cnt;  --i >= 0;) {
               y = val(p->bnd[i].sym);
               val(p->bnd[i].sym) = p->bnd[i].val;
               p->bnd[i].val = y;
            }
      } while (--n);
   }
   return Pop(c1);
}

// (quote . any) -> any
any doQuote(any x) {return cdr(x);}

// (box 'any) -> sym
any doBox(any x) {
   x = cdr(x);
   return consSym(EVAL(car(x)), Nil);
}

/* Evaluate method invocation */
static any evMethod(any o, any expr, any x) {
   any y = car(expr);
   any cls = TheCls, key = TheKey;
   struct {  // bindFrame
      struct bindFrame *link;
      int i, cnt;
      struct {any sym; any val;} bnd[length(y)+3];
   } f;

   f.link = Env.bind,  Env.bind = (bindFrame*)&f;
   f.i = sizeof(f.bnd) / (2*sizeof(any)) - 2;
   f.cnt = 1,  f.bnd[0].sym = At,  f.bnd[0].val = val(At);
   while (isCell(y)) {
      f.bnd[f.cnt].sym = car(y);
      f.bnd[f.cnt].val = EVAL(car(x));
      ++f.cnt, x = cdr(x), y = cdr(y);
   }
   if (isNil(y)) {
      while (--f.i > 0) {
         x = val(f.bnd[f.i].sym);
         val(f.bnd[f.i].sym) = f.bnd[f.i].val;
         f.bnd[f.i].val = x;
      }
      f.bnd[f.cnt].sym = This,  f.bnd[f.cnt++].val = val(This),  val(This) = o;
      y = cls,  cls = Env.cls;  Env.cls = y;
      y = key,  key = Env.key;  Env.key = y;
      x = prog(cdr(expr));
   }
   else if (y != At) {
      f.bnd[f.cnt].sym = y,  f.bnd[f.cnt++].val = val(y),  val(y) = x;
      while (--f.i > 0) {
         x = val(f.bnd[f.i].sym);
         val(f.bnd[f.i].sym) = f.bnd[f.i].val;
         f.bnd[f.i].val = x;
      }
      f.bnd[f.cnt].sym = This,  f.bnd[f.cnt++].val = val(This),  val(This) = o;
      y = cls,  cls = Env.cls;  Env.cls = y;
      y = key,  key = Env.key;  Env.key = y;
      x = prog(cdr(expr));
   }
   else {
      int n, cnt;
      cell *arg;
      cell c[n = cnt = length(x)];

      while (--n >= 0)
         Push(c[n], EVAL(car(x))),  x = cdr(x);
      while (--f.i > 0) {
         x = val(f.bnd[f.i].sym);
         val(f.bnd[f.i].sym) = f.bnd[f.i].val;
         f.bnd[f.i].val = x;
      }
      n = Env.next,  Env.next = cnt;
      arg = Env.arg,  Env.arg = c;
      f.bnd[f.cnt].sym = This,  f.bnd[f.cnt++].val = val(This),  val(This) = o;
      y = cls,  cls = Env.cls;  Env.cls = y;
      y = key,  key = Env.key;  Env.key = y;
      x = prog(cdr(expr));
      if (cnt)
         drop(c[cnt-1]);
      Env.arg = arg,  Env.next = n;
   }
   while (--f.cnt >= 0)
      val(f.bnd[f.cnt].sym) = f.bnd[f.cnt].val;
   Env.bind = f.link;
   Env.cls = cls,  Env.key = key;
   return x;
}

void
symeListSetExtension(SymeList symes, Syme syme)
{
	for (; symes; symes = cdr(symes))
		symeSetExtension(car(symes), syme);
}