Question

如何在duktape c函数中键入检查String对象/数字对象参数类型，并解析String对象/数字对象中的值。有像duk_is_object（）这样的通用API，但我需要正确的对象类型来解析值。

ex: 
ecmascript code
  var str1 = new String("duktape");
   var version = new Number(2.2);
 dukFunPrintArgs(str1,str2); 

duktape c function :
dukFunPrintArgs(ctx)
{
  // code to know whether the args is of type String Object / Number Object

}

Answer 1

您在哪里找到了如何在duktape中注册C函数的信息？那个地方当然也有关于如何访问传递给它的参数的详细信息。已经在duktape.org的主页上找到了一个入门示例：

3 Add C function bindings

To call a C function from Ecmascript code, first declare your C functions:

/* Being an embeddable engine, Duktape doesn't provide I/O
 * bindings by default.  Here's a simple one argument print()
 * function.
 */
static duk_ret_t native_print(duk_context *ctx) {
  printf("%s\n", duk_to_string(ctx, 0));
  return 0;  /* no return value (= undefined) */
}

/* Adder: add argument values. */
static duk_ret_t native_adder(duk_context *ctx) {
  int i;
  int n = duk_get_top(ctx);  /* #args */
  double res = 0.0;

  for (i = 0; i < n; i++) {
    res += duk_to_number(ctx, i);
  }

  duk_push_number(ctx, res);
  return 1;  /* one return value */
}

Register your functions e.g. into the global object:

duk_push_c_function(ctx, native_print, 1 /*nargs*/);
duk_put_global_string(ctx, "print");
duk_push_c_function(ctx, native_adder, DUK_VARARGS);
duk_put_global_string(ctx, "adder");

You can then call your function from Ecmascript code:

duk_eval_string_noresult(ctx, "print('2+3=' + adder(2, 3));");

duktape的核心概念之一是堆栈。值堆栈是存储参数的位置。请在Getting Started页面上阅读更多内容。

duktape如何在duktape c函数中解析String对象的类型参数（类似于Number对象）

1 个答案: