Databases
StackOverflow2013
Postsdbo
POBoost::python and iterators from base class virtual functions
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POBoost::python and iterators from base class virtual functions
    primarykey
    data
    text
    <p>So I'm trying to write a base class to handle classes that wrap std::vector, which I have working up to defining the __iter__ function. My first approach, and the one I wish to get working, is to have the begin() and end() functions in the base class. Doing this compiles fine, but when I run the code in python I get an error that looks simiar to:</p> <blockquote> <p>Boost.Python.ArgumentError: Python argument types in</p> <blockquote> <p>Container.__iter__(Container)</p> </blockquote> <p>did not match C++ signature:</p> <blockquote> <p>__iter__(boost::python::back_reference&lt; stl_iter&lt; std::vector&lt; std::shared_ptr&lt; K > > std::allocator&lt; std::shared_ptr&lt; K > > > >&amp;>)</p> </blockquote> </blockquote> <p>The following sample extension can be tested with </p> <pre class="lang-python prettyprint-override"><code>from test import * c = Container() for i in range(10): c.append(K(str(i))) for i in c: print i </code></pre> <p>Sample extension:</p> <pre class="lang-c++ prettyprint-override"><code>#include &lt;memory&gt; #include &lt;vector&gt; #include &lt;string&gt; #include &lt;boost/python.hpp&gt; template&lt;class T&gt; T* get_pointer(std::shared_ptr&lt;T&gt; const&amp; p) { return p.get(); } template&lt;class T&gt; class stl_iter { protected: typedef typename T::value_type V; typedef typename T::iterator iter; virtual T&amp; get_vector()=0; public: virtual ~stl_iter() {} virtual void append(V item) { get_vector().push_back(item); } virtual iter begin() { return get_vector().begin(); } virtual iter end() { return get_vector().end(); } }; class K { std::string val; public: K(std::string s) : val(s) {} std::string get_val() const { return val; } }; typedef std::shared_ptr&lt;K&gt; pK; typedef std::vector&lt;pK&gt; vK; class Container : public stl_iter&lt;vK&gt; { vK items; protected: vK&amp; get_vector() { return items; } public: // Works if I uncomment these //vK::iterator begin() { return get_vector().begin(); } //vK::iterator end() { return get_vector().end(); } public: virtual ~Container() {} }; typedef std::shared_ptr&lt;Container&gt; pContainer; typedef std::vector&lt;pContainer&gt; vContainer; BOOST_PYTHON_MODULE_INIT(test) { using namespace boost::python; class_&lt;K, pK&gt;("K", init&lt;std::string&gt;()) .def("__str__", &amp;K::get_val) ; class_&lt;Container, pContainer&gt;("Container") .def("append", &amp;Container::append) .def("__iter__", range(&amp;Container::begin, &amp;Container::end)) ; } </code></pre>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. This table or related slice is empty.
    1. USNaddiseo
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POBoost::python and iterators from base class virtual functions
      1. This table or related slice is empty.
      1. VTUpMod
    1. CODo I understand correctly that the point of this is to expose vector types using boost python? And to do this in a general way?
      singulars
      1. POBoost::python and iterators from base class virtual functions
      1. USMatthew Scouten
    2. COI get this error trying to run a (non-c++11) adapted version of your code: `TypeError: __init__() should return None, not 'NoneType'` if I try to instantiate a `Container`.
      singulars
      1. POBoost::python and iterators from base class virtual functions
      1. USJames
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload