岗周 发表于 2006-12-8 18:49:00

让你的python脚本支持boost::any的格式。

<p></p><p>当你有个C++函数:<br/>boost::any&nbsp;Get(std::string)<br/>{<br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;.....<br/>}</p><p>void&nbsp;Set(std::string,&nbsp;boost::any)<br/>{<br/>&nbsp;&nbsp;&nbsp;&nbsp;.....<br/>}</p><p>这样的两个API要传给python来执行的话,当你运行<br/>a.set('hehe',&nbsp;1);<br/>返回的是类型不匹配。那么如何来修改boost.python,让它支持boost::any的格式呢,大家看过来:</p><p>首先打开你boost目录下的boost/python/converter/builtin_converters.hpp<br/>在namespace&nbsp;converter里加上一句:<br/>&nbsp;BOOST_PYTHON_DECL&nbsp;PyObject*&nbsp;do_return_to_python(boost::any);</p><p>然后加一句宏定义:<br/>BOOST_PYTHON_TO_PYTHON_BY_value(boost::any,&nbsp;converter::do_return_to_python(x))</p><p>然后打开libs/python/src/converter/builtin_converters.cpp加上一段:<br/>BOOST_PYTHON_DECL&nbsp;PyObject*&nbsp;do_return_to_python(boost::any&nbsp;x)<br/>{<br/>if(x.type()&nbsp;==&nbsp;typeid(int))<br/>return&nbsp;PyInt_FromLong(any_cast&lt;int&gt;(x));</p><p>if(x.type()&nbsp;==&nbsp;typeid(float))<br/>return&nbsp;PyFloat_FromDouble(any_cast&lt;float&gt;(x));</p><p>if(x.type()&nbsp;==&nbsp;typeid(double))<br/>return&nbsp;PyFloat_FromDouble(any_cast&lt;double&gt;(x));</p><p>try{<br/>std::string&nbsp;str&nbsp;=&nbsp;any_cast&lt;std::string&gt;(x);<br/>return&nbsp;PyString_FromStringAndSize(str.data(),implicit_cast&lt;int&gt;(str.size()));<br/>}&nbsp;catch&nbsp;(bad_any_cast&nbsp;&amp;)<br/>{<br/>return&nbsp;PyInt_FromLong(0);<br/>}<br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;todo,&nbsp;新加对list,map,vector等的支持<br/>}</p><p>ok,&nbsp;bjam一下,发现get好使了,呵呵。。然后来看set如何让它好使,set所需要的是python&nbsp;to&nbsp;c++的类型转换:<br/>在libs/python/src/converter/builtin_converters.cpp里找到initialize_builtin_converters()这个函数,在里头加上一句:<br/>slot_rvalue_from_python&lt;boost::any,&nbsp;any_rvalue_from_python&gt;();</p><p>然后在相同的文件里加上一个函数:<br/>&nbsp;&nbsp;struct&nbsp;any_rvalue_from_python<br/>&nbsp;&nbsp;{<br/>&nbsp;&nbsp;static&nbsp;unaryfunc&nbsp;*get_slot(PyObject&nbsp;*obj)<br/>&nbsp;&nbsp;{<br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if(PyInt_Check(obj)&nbsp;||&nbsp;PyString_Check(obj)&nbsp;||&nbsp;PyFloat_Check(obj))<br/>return&nbsp;&amp;py_object_identity;</p><p>&nbsp;&nbsp;return&nbsp;0;<br/>&nbsp;&nbsp;}</p><p>&nbsp;&nbsp;static&nbsp;boost::any&nbsp;extract(PyObject&nbsp;*obj)<br/>&nbsp;&nbsp;{<br/>&nbsp;&nbsp;boost::any&nbsp;res&nbsp;=&nbsp;boost::any();<br/>&nbsp;&nbsp;if(PyInt_Check(obj))<br/>&nbsp;&nbsp;{<br/>&nbsp;&nbsp;int&nbsp;a&nbsp;=&nbsp;PyInt_AS_LONG(obj);<br/>&nbsp;&nbsp;res&nbsp;=&nbsp;a;<br/>&nbsp;&nbsp;}</p><p>&nbsp;&nbsp;if(PyFloat_Check(obj))<br/>&nbsp;&nbsp;{<br/>&nbsp;&nbsp;float&nbsp;f&nbsp;=&nbsp;(float)PyFloat_AS_DOUBLE(obj);<br/>&nbsp;&nbsp;res&nbsp;=&nbsp;f;<br/>&nbsp;&nbsp;}</p><p>&nbsp;&nbsp;if(PyString_Check(obj))<br/>&nbsp;&nbsp;{<br/>&nbsp;&nbsp;std::string&nbsp;str(PyString_AsString(obj),PyString_Size(obj));<br/>&nbsp;&nbsp;res&nbsp;=&nbsp;str;<br/>&nbsp;&nbsp;}<br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;todo,&nbsp;新增对map,list,vector等的支持<br/>&nbsp;&nbsp;return&nbsp;res;<br/>&nbsp;&nbsp;}<br/>&nbsp;&nbsp;};</p><p>OK,你会发现set也好使了,呵呵,等把对map,list,vector的支持全做完,就打算把这个修改提交到boost的maillist里了:)</p>
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