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PODynamic C++
 

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    <p>I'm wondering about an idea in my head. I want to ask if you know of any library or article related to this. Or you can just tell me this is a dumb idea and why.</p> <p>I have a class, and I want to dynamically add methods/properties to it at runtime. I'm well aware of the techniques of using composite/command design pattern and using embedded scripting language to accomplish what I'm talking about. I'm just exploring the idea. Not necessary saying that it is a good idea.</p> <pre><code>class Dynamic { public: typedef std::map&lt;std::string, boost::function&lt;void (Dynamic&amp;)&gt; &gt; FuncMap; void addMethod(const std::string&amp; name, boost::function&lt;void (Dynamic&amp;)&gt; func) { funcMap_[name] = func; } void operator[](const std::string&amp; name) { FuncMap::iterator funcItr = funcMap_.find(name); if (funcItr != funcMap_.end()) { funcItr-&gt;second(*this); } } private: FuncMap funcMap_; }; void f(Dynamic&amp; self) { doStuffWithDynamic(self); } int main() { Dynamic dyn; dyn.addMethod("f", boost::bind(&amp;f, _1)); dyn["f"]; // invoke f } </code></pre> <p>The idea is that I can rebind the name "f" to any function at runtime. I'm aware of the performance problem in string lookup and boost::function vs. raw function pointer. With some hard work and non-portable hack I think I can make the performance problem less painful.</p> <p>With the same kind of technique, I can do "runtime inheritance" by having a "v-table" for name lookup and dispatch function calls base on dynamic runtime properties.</p> <p>If just want to tell me to use smalltalk or Objective-C, I can respect that but I love my C++ and I'm sticking with it.</p>
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    1. COIt would be better if "operator[](const std::string& name)" returned a boost::function object so making the syntax a bit more natural "dyn["f"]()", this would allow the possibility of parameters and "function pointers" (which would really just be instances of boost::function
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    2. CODon't "love your C++". Use the language that is best suited for the task at hand, *not" the one you "love", or the only one you know.
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    3. COI usually drive to the corner store to get milk. Sometimes I walk to get milk. I walk not because I didn't know how to drive or not understand driving is faster than walking. I do it for the same reason my math geek friend spend days and weeks solving an equation which his simulator can given him the answer in seconds. I do it for the exercise. People see me walking and trying to help by telling me I should drive because it is faster. Thank you, but I'm walking.
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