added a function to import a c++ class similar to the 'algorithm'.

This makes it possible to import "statefull" C++ objects to Python.
At the moment only the constructor is available on the Python side
so the object can only be used as argument for another C++ function/method.
Exporting methods will be made available as well in a future version.

CMakeLists.txt

 add_python_targets(generator
   __init__
   algorithm
+  importclass
   builder
   exceptions
   generator

__init__.py

@@ -51,7 +51,7 @@ class Constructor(object):
 
     def register(self, cls="cls"):
         if self.body is None:
-            return cls + ".def( pybind11::init( " + args + " )" + "".join(", " + e for e in self.extra) + " );\n"
+            return cls + ".def( pybind11::init( " + self.args + " )" + "".join(", " + e for e in self.extra) + " );\n"
         if self.args:
             source = cls + ".def( pybind11::init( [] ( " + ", ".join(self.args) + " ) {"
         else:

generator.py

@@ -11,6 +11,7 @@ from __future__ import absolute_import, division, print_function, unicode_litera
 import logging
 
 from . import builder
+from dune.common.hashit import hashIt
 
 logger = logging.getLogger(__name__)
 
@@ -146,7 +147,6 @@ class SimpleGenerator(object):
                                 baseClasses=bc)
         return self.post(moduleName, source)
 
-from dune.common.hashit import hashIt
 def simpleGenerator(inc, baseType, namespace, pythonname=None, filename=None):
     generator = SimpleGenerator(baseType, namespace, pythonname, filename)
     def load(includes, typeName, *args):

importclass.py

+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import os
+
+from dune.common.hashit import hashIt
+from . import builder
+from dune.common.compatibility import isString
+from dune.generator.algorithm import cppType
+
+def load(className, includeFiles, *args):
+    source = '#include <config.h>\n\n'
+    source += '#define USING_DUNE_PYTHON 1\n\n'
+    includes = []
+    if isString(includeFiles):
+        if not os.path.dirname(includeFiles):
+            with open(includeFiles, "r") as include:
+                    source += include.read()
+            source += "\n"
+        else:
+            source += "#include <"+includeFiles+">\n"
+            includes += [includeFiles]
+    elif isinstance(includeFiles, list):
+        for includefile in includeFiles:
+            if not os.path.dirname(includefile):
+                with open(includefile, "r") as include:
+                    source += include.read()
+                source += "\n"
+        else:
+            source += "#include <"+includefile+">\n"
+            includes += [includefile]
+
+    argTypes = []
+    for arg in args:
+        t,i = cppType(arg)
+        argTypes.append(t)
+        includes += i
+
+    signature = className + "( " + ", ".join(argTypes) + " )"
+    moduleName = "class_" + hashIt(signature) + "_" + hashIt(source)
+
+    includes = sorted(set(includes))
+    source += "".join(["#include <" + i + ">\n" for i in includes])
+    source += "\n"
+    source += '#include <dune/python/common/typeregistry.hh>\n'
+    source += '#include <dune/python/pybind11/pybind11.h>\n'
+    source += '\n'
+
+    source += "PYBIND11_MODULE( " + moduleName + ", module )\n"
+    source += "{\n"
+
+    source += "  auto cls = Dune::Python::insertClass< "+className+\
+                 " >( module, \"cls\","+\
+                 "Dune::Python::GenerateTypeName(\""+className+"\"),"+\
+                 "Dune::Python::IncludeFiles{"+",".join(["\""+f+"\"" for f in includes])+"}).first;\n"
+    ctorArgs = ", ".join([argTypes[i] + " arg" + str(i) for i in range(len(argTypes))])
+    source += "cls.def( pybind11::init( [] ( "+ctorArgs+" ) {\n"
+    source += "return new "+className+"( "+",".join(["arg"+str(i) for i in range(len(argTypes))]) +"); \n"
+    source += " }));\n"
+    source += "}"
+
+    return builder.load(moduleName, source, signature).cls(*args)