访问C ++函数从文本存储

问题描述

我想知道是否有人知道如何完成以下操作：

I'm wondering if anyone knows how to accomplish the following:

假设我有一堆数据存储在SQL中，让我们说一个字段被称为funcName，函数名将包含类似于myFunction的数据我想知道是否有一种方式，我可以反过来提取函数名称，实际上调用该函数？

Let's say I have a bunch of data stored in SQL, lets say one of the fields could be called funcName, function name would contain data similar to "myFunction" What I'm wondering is, is there a way I can than in turn extract the function name and actually call that function?

有几种方法我可以想到来实现这一点，一个是将funcName更改为funcId和链接数组或类似，但我正在寻找一些更动态的东西，将允许我添加数据，而不必在每次添加对新函数的调用时更新实际的源代码，假设函数已经存在并且可以通过范围位置访问。

There's a few ways I can think of to accomplish this, one is changing funcName to funcId and linking up with an array or similar, but I'm looking for something a bit more dynamic that would allow me to add the data on fly without having to update the actual source code every time I add a call to a new function assuming of course that the function already exists and is accessible via scope location we call it from.

任何帮助将非常感激。

推荐答案

使用宏来定义自动注册自己的新函数。 / p>

Use a macro to define new functions that register themselves automatically.

// callable_function.h
class CallableFunction {
 public:
  virtual void operator()() = 0;
};

class CallableFunctionRegistry {
 public:
  static CallableFunction *Register(const string &func_name,
                                    CallableFunction *func_impl) {
    Instance()->registered_functions_.insert(make_pair(func_name, func_impl));
  }

  static void Run(const string &func_name) {
    (*Instance()->registered_functions_[func_name])();
  }

 private:
  static CallableFunctionRegistry *Instance() {
    static CallableFunctionRegistry *instance = new CallablefunctionRegistry;
    return instance;
  }

  CallableFunctionRegistry() {}
  map<string, CallableFunction*> registered_functions_;
};

#define REGISTER_CALLABLE_FUNCTION(FuncName) \
  class FuncName : public CallableFunction { \
   public: \
    virtual void operator()(); \
  }; \
  CallableFunction *impl_ ##FuncName = \
    CallableFunctionRegistry::Register(#FuncName, new FuncName); \
  void FuncName::operator()()

//other_file.cc
REGISTER_CALLABLE_FUNCTION(DoStuff) {
  // do stuff here.
}

而且：

//yet_another_file.cc
CallableFunctionRegistry::Run("DoStuff");

你可以使用函数ptrs而不是CallableFunction对象，但是我的语法是模糊的。无论如何，添加错误检查重复注册和查找未找到。

You could do it with function ptrs instead of CallableFunction object, but my syntax on that is hazy. Either way, add error checking for duplicate registrations and lookup not found.

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